WEMPEC Research Reports

Year ID Title Publisher Keywords Abstract Authors
1981-001 001 Modelling and simulation of induction motors with saturable leakage reactance In proc. of IEEE IAS Annual Meeting, Philadelphia, PA, Oct. 5-9, 1981, pp.527-35, and in IEEE Trans. on Ind. Appl. January/February 1984. Vol 20. No. 1. pp. 180-189. A new method for the transient analysis of induction machines with saturating leakage reactances is presented. The equations which define operation under this condition are arranged so that the saturation of stator and rotor leakage as well as magnetizing reactance can be readily modeled with three function generators. The method is equally applicable to the analysis of synchronous machines. A. Consoli, T.A. Lipo
1981-002 002 The stator voltage controlled current source inverter induction motor drive In Proc. of IEEE IAS Annual Meeting, Philadelphia, PA, Oct. 5-9, 1981, pp. 578-85, and in IEEE Trans. on Ind. Appl. May/June 1982. Vol. 18. No. 3. pp. 219-229. The steady and state dynamic performance of a stator voltage controlled current source inverter induction motor drive are presented. Commutation effects are neglected and the analytical results are based on the fundamental component. A synchronously rotating reference frame linearized model in terms of a set of non-dimensional parameters based on the rotor transient time constant is developed. It is shown that the control scheme is capable of stabilizing the drive over a region identical to the statically stable region of a conventional voltage fed induction motor. A simple approximate expression for the drive dominant poles under no load conditions and graphical representations of the drive dynamics under load conditions are presented. The effect of parameter variations on the drive dynamic response ca be evaluated from these results. An analog simulation of the drive is developed and the results confirm the small signal analysis of the drive system. In addition, the steady state results of the analog simulation are compared with experimental results as well as with corresponding values obtained from a stator referred equivalent circuit. The comparison indicates good correspondence under load conditions and the limitation of applying the equivalent circuit for no load conditions without proper recognition of the system losses. M. Abbas, D.W. Novotny
1981-003 003 Inverter gate signal generation using a microprocessor Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1981. It is shown that a simple and inexpensive microprocessor system can be used to generate the gate signals needed by a voltage source inverter. A prototype system has been built. The software and hardware are described. The software is designed in such a way as to leave enough time for feedback control functions. D. Kirschen, N. Schmitz
1981-004 004 Characteristic induction motor slip values for variable voltage part load performance optimization IEEE-PAS Conf. Rec. January 1983. Vol. 102. No. 1. pp. 38-46. Minimum input power and maximum efficiency occur at a characteristic optimum slip value which can be calculated for any induction motor using methods described. Efficiency is shown to be independent of output power when a variable voltage controller reduces the voltage approximately as the square root of the load torque to maintain the required slip during part load operation. Saturation effects do not significantly change these results. Although a characteristic value of power factor corresponds to optimum slip in the linear motor, it is shown that with saturation there is no single value of optimal power factor. It is also shown that minimum current operation results in much less than optimum efficiency because it requires much smaller than optimum slip. T.W. Jain, D.W. Novotny
1981-005 005 Orthogonal axis models for asymmetrical connected induction machines IEEE Trans. on Power Apparatus & Sys. December 1982. Vol. PAS-101. No.12. pp. 4518-4526. This paper presents a new method for the transient analysis of induction machines with asymmetrical connection of the stator phases. The method is based on the unified theory of electrical machines and sets forth a convenient framework for depicting the machine together with the constraints of the system to be studied. Equivalent d-q-0 circuits are reduced for a number of specific connections and results of analog computer simulation used to illustrate the proposed procedure. A. Consoli, T.A. Lipo
1982-001 001 Hybrid computer simulation of an ASCI current source inverter Elect. Machine & Electromech. January/February 1983. Vol. 8. No. 1. pp. 1-15. A hybrid computer representation of a current source inverter is described. The inverter is modeled in considerable detail so that the simulation is suitable to portray double overlap, discontinuous current operation and other abnormal modes of inverter behavior. Both system equations and simulation diagrams are included. Several computer runs are shown to illustrate the simulation of typical inverter operation. T.A. Lipo
1982-002 002 A quantitative analysis of induction motor performance improvement by SCR voltage control IEEE-IAS Trans. July/August 1983. Vol. IA-19. No. 4. pp. 545-553. Minimum input power and maximum efficiency operation occur at characteristic slip values which can be realized for any induction motor operating at part load by properly adjusting the amplitude of the applied stator terminal voltages. These two criteria are shown to yield perceptibly different results when the motor is driven from a silicon-controlled rectifier (SCR) voltage controller. In addition, it is demonstrated that a constant power factor controller results in an operating regime which is substantially poorer than operation at either minimum input power or maximum efficiency. It is further shown that minimum stator current and minimum power factor angle criteria yield results which are closer to the ideal than the constant power factor controller. T.M. Rowan, T.A. Lipo
1982-003 003 A flywheel energy storage system having harmonic power compensation IPEC-Tokyo Conf. Rec. of the Int'l Power Elect. Conf., Inst. Electr. Eng, Tokyo, Japan, 1983. Vol. 2 xii+1821. pp.1072-1083. A flywheel mechanical energy storage system which possesses power distortion compensation ability is described. The system functions as an active filter which compensates not only flicker current but also reactive or unbalanced components of current. The system can also control the active and reactive current flow of the line according to its command signal. The system to be described is composed of a flywheel driven synchronous machine together with a natural commutated cascade cycloconverter. The cycloconverter has two control capabilities. First, the converter is able to control the reactive current component of the input which enables high speed voltage control of the machine. The other function is minimum time control on the output current which makes it possible to eliminate the random flicker distortion current from a power line to within 0.2~0.3 msec. The system validity is confirmed by a digital simulation technique and it is demonstrated that compensation characteristics are very excellent for the power distortion compensating system. I. Takahashi
1982-004 004 The influence of saturation on induction machines drive dynamics In Proc. of IEEE-IAS Annual Meeting, New York, NY, 1982, 1405 pp. 468-76, and in IEEE-IAS Trans. on Ind. Appl., Vol. IA-19, No. 5, Sept/Oct 1983, pp. 671-681. A small signal model which employs two different magnetizing reactances to incorporate the effect of main flux saturation on induction machine dynamic response is presented. Three different types of the saturated model are discussed and the model is used to examine the effect of saturation on dynamic response in variable frequency applications. The results indicate that whereas saturation has a relatively small effect under normal operating conditions, it does have an important stabilizing effect when the damping is poor. It is also shown that neglecting saturation leads to significant errors in both pole and zero locations when the operating frequency is low. J.A.A. Melkebeek, D.W. Novotny
1982-005 005 Design and performance of a converter optimized AC machine In Proc. of IEEE-IAS Annual Meeting, New York, NY, 1982, 1405 pp. 491-9, and in IEEE-IAS Trans. on Ind. Appl. July/August 1984. Vol. 20. No. 4. pp. 834-844. The design and performance of a unique concentrated winding machine specifically designed for operation with a static power converter is described. When operating in conjunction with a converter supply, the machine is theoretically capable of 15% more power output for the same active copper and iron than a conventionally designed synchronous machine of the same rating. Performance of the machine operating as a generator feeding a rectifier load is described and theoretical predictions are compared with test. The potential of such a machine operating as a motor is also described. T.A. Lipo, F.X. Wang
1982-006 006 Design and control techniques for extending high frequency operation of a CSI induction motor drive In proc. of IEEE-IAS Annual Meeting, New York, 1982, 1405 pp. 698-706, and in IEEE-IAS Trans. on Ind. Appl.,Vol. IA-19, No. 15, Sept/Oct 1983. pp. 744-753. An investigation of the maximum speed capability of a current source inverter (CSI)drive in both a three- and a six-phase connection is presented. It is shown that a six-phase configuration has distinct advantages over a three-phase connection in high speed capability for the same peak motor spike voltages. In addition, with proper control of the firing pulses fed to the inverters supplying the six-phase machine, the speed range can be substantially extended beyond the maximum limit predicted using conventional control. Predicted analytical results are correlated with results obtained by a detailed hybrid computer simulation. T.A. Lipo, L.H. Walker
1982-007 007 Scaling Laws for AC Electric Machines Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1982. D. W. Novotny
1982-008 008 Analysis and steady state behavior of an optimized AC converter machine In Proc. of IEEE-IAS Annual Meeting, San Francisco, Oct. 4-8, 1982, pp. 491-9, and in IEEE-IAS Trans. on Ind. Appl., Vol. IA-20, No. 4. July/Aug 1984. pp. 834-844. At present, AC machines for adjustable speed drives retain a sinusoidal winding distribution even through such machines were originally intended for sinusoidal power supplies. This paper describes a unique concentrated winding machine in which the winding distribution is intentionally rectangular to better accommodate the rectangular waveforms of conventional six pulse converters. Equations which define steady state are derived and compared with tested results on an actual prototype. Both generating and motoring modes are investigated and conditions are identified for optimal operation of this new machine. F.X. Wang, T.A. Lipo
1982-009 009 Computer simulation of an induction machine with spatially dependent saturation IEEE-PAS Trans. April 1984. Vol. 103. No. 4. pp. 707-714. This paper presents a new analog computer model for the simulation of an induction machine which takes into account the spatially dependent main flux saturation effect. Using this model of saturation, an unstable operation region for a voltage fed induction motor with high source impedance has been calculated and has been correlated with both test results and the results predicted by the conventional linearized model. This study clearly demonstrates an improvement over the linearized model in predicting machine dynamic behavior. Because the simulation accurately models large signal as well as small signal behavior, it should prove equally useful in predicting transient behavior. The manner of dealing with saturation of the magnetizing field presented in this paper can be readily implemented on a digital as well as an analog computer and can also be extended to the study of other electrical machines. Y.K. He, T.A. Lipo
1982-010 010 Steady state modelling of regeneration and self-excitation in induction motor drives IEEE-PAS. August 1983. Vol. 102. No. 8. pp. 2725-2733. Six modes of source-connected and self-excited induction generator operation including both voltage(VSI) and current (CSI) inverter systems and reviewed and compared. Equivalent circuits to represent each mode are presented and the use of the circuits to model steady state performance is illustrated. The analysis clearly shows the fundamental importance of main flux saturation in the self-excited cases as compared to its secondary importance in source-connected systems. General properties of regeneration and self-excitation are derived to illustrate the basic similarities and differences between the various modes. Experimental results which support the validity of the models used in the study are included J.A.A. Melkebeek, D.W. Novotny
1982-011 011 PWM inverter waveform for minimum loss operation of an induction motor drive IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS. VOL. IA-21. NO. 4, MAY/JUNE 1985. I. Takahashi
1982-012 012 Comparative analysis of permanent magnet AC machines for use in variable speed applications Department of Electrical and Computer Engineering, University of Wisconsin-Madison, April 1995. T.A. Lipo
1982-013 013 Saturation effects in the stability analysis of a VSI induction motor drive Trans. of the Instit. of Elec. Eng. of Japan. November-December 1983. Section E. Vol. 103. No.11-12. pp.117-124. A computer model of a saturated induction machine is introduced which takes into account the effect of spatially dependent main-flux saturation. The approach is used to model a voltage source inverter (VSI) drive and the instability region of such a drive system is predicted with the new saturation model. Comparison of the results predicted by the conventional quasilinear model indicate surprisingly important effects of saturation on the small as well as large signal behavior (transients) of a drive system. Discrepancies which have long existed between theory and practice concerning the prediction of dynamic instability of VSI drive by the small signal theory are resolved. Y.K. He, T.A. Lipo
1983-001 001 Small signal dynamic analysis of regeneration and self-excitation in induction machines Elect. Machine & Power Systems. July/Oct 1983. Vol. 8. No. 4-5. pp. 259-280. Small signal stability and dynamic response is examined and compared for six modes of source-connected and self-excited induction generator operation including both voltage (VSI) and current (CSI) inverter systems. It is shown that conventional small signal machine modelling is incapable of yielding any information whatsoever concerning the stability of self-excitation at constant speed. A recently introduced small signal model which includes main flux saturation overcomes these difficulties and is employed to study the stability properties of all six modes. General stability and dynamic response properties of each mode are summarized and compared, especially with respect to the influence of saturation. The capacitive self-excited case is shown to require special treatment because of the phase freedom inherent in this mode. Experimental confirmation of some of the results is included. J.A.A. Melkebeek,
1983-002 002 Minimizing induction motor losses by excitation control in variable frequency drives In Proc. of IEEE-IAS Annual Meeting,Mexico City, Oct. 3-7, 1983, pp. 526-33, and in IEEE Trans. on Ind. Appl. September/October 1984, Vol. 20, No. 5, pp. 1244-1251. D. Kirschen, D.W. Novotny, W. Suwanisoot
1983-003 003 Field weakening in buried permanent magnet AC motor drives In Proc. of IEEE-IAS 1983 Annual Meeting, Mexico City, Oct. 3-7, 1983, pp. 462-8., and in IEEE Trans. on Ind. Appl., Vol. IA-21, No. 2, March/April 1985, pp. 398-407. B. Sneyers, D.W. Novotny, T.A. Lipo
1983-006 006 Automated small signal analysis of AC drive systems IMACS IC-1 Symposium. Special Issue. May 1984. pp. 41-48. D.S. Zinger, D.W. Novotny
1984-001 001 Considerations in the design of tubular linear induction motors for variable frequency operation International Conference on Electrical Machines. September 18-21, 1984. Vol. 2. pp. 493-496. A.A. Fahim, D.W. Novotny
1984-002 002 A cartesian vector approach to reference frame theory of AC machines International Conference on Electrical Machines. September 18-21, 1984. Vol. 1. pp. 239-242. T.A. Lipo
1984-003 003 The influence of motor parameter deviations in feedforward field orientation drive systems IEEE-IAS Conf. Rec. 1984. pp. 488-493. IEEE Trans. on Ind. Appl. July/August 1985. Vol. 21. No. 4. pp. 525-31. K. Nordin
1984-004 004 Variable speed generator technology options for wind turbine generators DOE/NASA Workshop on HAWT Technology. May 8-10, 1984. T.A. Lipo
1984-005 005 A state space analysis of LCI fed synchronous motor drives in the steady state IEEE-IAS Conf. Rec. 1984. pp. 439-444. IEEE Trans. on Ind. Appl. July/August 1985. Vol. 21. No. 4. pp. 1016-1022. R.S. Colby, T.A. Lipo, D.W. Novotny
1984-006 006 Current control ov VSI-PWM inverters IEEE-IAS Conf. Rec. 1984. pp. 418-425. IEEE Trans. on Ind. Appl. May/June 1985. Vol. 21. No. 3. pp. 562-570. D.M. Brod, D.W. Novotny
1984-007 007 A rotor parameter identification scheme for vector controlled induction motor drives IEEE-IAS Conf. Rec. 1984. pp. 538-545. IEEE Trans. on Ind. Appl. May/June 1985. Vol. 21. No. 3. pp. 624-632. T. Matsuo, T.A. Lipo
1984-008 008 The influence of motor parameter deviations in feedforward field orientation drive systems IEEE-PESC Conf. Rec. 1984. pp. 190-197. IEEE Trans. on Power Elec. October 1986. Vol. 1. No 4. pp. 240-247. IEEE Trans. on Ind. Appl. July/August 1985. Vol. 21. No. 4. pp. 1009-1015. K.B. Nordin, D.W. Novotny, D.S. Zinger
1984-009 009 On-line efficiency optimization of a variable frequency induction motor drive IEEE-IAS Conf. Rec. 1984. pp. 488-493. IEEE Trans. on Ind. Appl. May/June 1985. Vol. 21. No. 3. pp. 610-616. D.S. Kirschen, D.W. Novotny, T.A. Lipo
1984-010 010 Induction machine phase balancing by unsymmetrical thyristor voltage control IEEE Trans. on Ind. Appl. May/June 1985. Vol. 21. No. 3. pp. 669-679. E. Muljadi, R. Schiferl, T.A. Lipo
1984-011 011 Hybrid computer simulation of a field oriented induction motor drive Fifth Brazilian/First Latin American Conf. on Automatic Control. Sept 3-6, 1984. T. Matsuo, T.A. Lipo
1984-012 012 An analysis of LCI synchronous motor drives with finite DC link inductance IEE Elect. Power Appl. Conf. Rec. November 1993. Vol. 140. No. 6. pp. 379-386. R.S. Colby, M.D. Otto, J.T. Boys
1984-013 013 Application of magnetic equivalent circuits in transient and steady state machine analysis Department of Electrical and Computer Engineering University of Wisconsin-Madison, 1984 V. Ostovic
1985-001 001 A method for evaluation of transient and steady state performance in saturated squirrel cage induction machines IEEE Trans. on Energy Conversion. Sept 1986. Vol. EC-1, No. 3. pp. 190-197. V. Ostovic
1985-002 002 Computation of saturated permanent magnet AC motor performance by means of magnetic circuits IEEE-IAS Conf. Rec. 1985. Vol. 1. pp. 794-799. IEEE Trans. on Ind. Appl. September/October 1987. Vol. IA-23. No. 4. pp. 836-841. V. Ostovic
1985-003 003 Determination of equivalent circuits for induction machines with skin effect using terminal characteristics Electric Machines & Power Systems. 1985. Vol. 10. No. 5 & 6. pp. 379-394. W.H. Creer, D.W. Novotny, T.A. Lipo
1985-004 004 Feasibility study of regenerative induction motor drive employing a bi-directional high frequency link converter Department of Electrical and Computer Engineering, University of Wisconsin-Madison, June 1995. P. Sood, T.A. Lipo
1985-005 005 A pulse width controlled three switch exciter for induction generators IEEE-IAS Conf. Rec. October 6-11, 1985. pp. 653-661. P.K. Sood, H. Rehaoulia, D.W. Novotny, T.A. Lipo
1985-006 006 An equivalent circuit model for phase back voltage control of AC machines IEEE-IAS Conf. Rec. 1985. pp. 798-804. IEEE Trans. on Ind. Appl. September/October 1986. Vol. 22. No 5. pp. 835-841. F.M.H. Khater, D.W. Novotny
1985-007 007 A modified control method for fast response current source inverter drives IEEE-IAS Conf. Rec. 1985. pp. 662-71. IEEE Trans. on Ind. Appl. July/August 1986. Vol. 22. No. 4. pp. 653-665. D. Deng, T.A. Lipo
1985-008 008 A new approach to flux and torque sensing in induction machines IEEE Trans. on Ind. Appl. July/August 1986. Vol. 22. No. 4. pp. 731-737. T.A. Lipo, K.C. Chang
1985-009 009 Torque characteristics of field oriented induction machines Proceedings of the Conf. on Applied Motion Control, June 11-13, 1985, pp. 101-107. J.M. Loehrke, R.D. Lorenz, D.W. Novotny
1985-010 010 Tuning of field oriented induction motor controllers for high performance applications In Proc. of IEEE-IAS Conf. Rec. 1985, Toronto, Oct. 6-11, pp. 607-612, and in IEEE Trans. on Ind. Appl., Vol. 1A-22, No. 2, March/April 1986, pp. 293-297. R.D. Lorenz
1985-011 011 A new synchronous current regulator and an analysis of current regulated PWM inverters IEEE Trans. on Ind. Appl. July/Aug 1986. Vol. IA-22. No. 4. pp. 678-690. T.M. Rowan, R.J. Kerkman
1985-012 012 Optimal efficiency control of an induction motor drive IEEE-PES Trans. on Energy Conversion. March 1987. Vol. EC-2. No. 1. pp. 70-76. D.S. Kirschen, D.W. Novotny, T.A. Lipo
1985-013 013 An investigation of the influence of deep-bar effect on the resistance of cage rotor end-rings IEEE-IAS Conf. Rec. September-October, 1986. Part 1. pp. 852-857. IEEE Trans. on Ind. Appl. July/August 1987. Vol. 23. No. 4. pp. 696-704. S. Williamson, R. Schiferl
1986-001 001 A simplified approach to magnetic equivalent circuit modelling of induction machines IEEE-IAS Conf. Rec. Sept 28 - Oct 3 1986. Part 1. pp. 846-851. IEEE Trans. on Ind. Appl. March/April 1988. Vol. 24. No. 2. pp. 308-316 V. Ostovic
1986-002 002 Single phase induction motor with an electronically controlled capacitor IEEE Trans. on Ind. Appl. January/February 1991. Vol. 27. No. 1. pp. 38-43. T. Lettenmaier
1986-003 003 Power factor enhancement of induction machines by solid state excitation Int'l Conf. on Evolution and Modern Aspects of Induction Machines (ICEMAIM). July 8-11, 1986. pp. 424-430. IEEE Trans. on Power Elect. October 1989. Vol. 4. No. 4. pp. 409-418. E. Muljadi, T.A. Lipo, D.W. Novotny
1986-004 004 Computation of saturated permanent magnet AC motor performance by means of magnetic circuits IEEE-IAS Conf. Rec. September/October 1987. pp. 794-799. V. Ostovic
1986-005 005 Design considerations for very high frequency resonant mode DC/DC converters IEEE-IAS Conf. Rec. 1986. pp. 640-647. IEEE Trans. on Power Elect. January 1987. Vol. PE-2. No. 1. pp. 45-54. D.M. Divan
1986-006 006 A new approach to induction motor torque and speed control Conf. on Applied Motion Control (CAMC). June 10-12, 1986. pp. 25-29. F. Benzi, D. Zinger, T.A. Lipo, M. Kramer
1986-007 007 Measurement of induction motor torque pulsations due to inverter supply NATO Conference on Electrical Machines. Aug 1986. Louvain, Belgium and Vibrations & Audible Noise in Electrical Machines. Martinus Nijhoff. 1988. pp. 191-211. T.A. Lipo, M.E. Kramer
1986-008 008 Synthesis of state variable controllers for industrial servo drives Proceedings of the Conference on Applied Motion Control, pp. 247-251, June 10-12, 1986. R.D. Lorenz
1986-009 009 Operation of naturally sampled current regulators in the transition region IEEE-IAS Conf. Rec. 1986. Vol. 1. pp. 91-98. IEEE Trans. on Ind. Appl. July/August 1987. Vol. 23. No. 4. pp. 586-596. T.M. Rowan, R.J. Kerkman, T.A. Lipo
1986-010 010 An automated rotor time constant measurement system for indirect field oriented drives IEEE-IAS Conf. Rec. 1986. Vol. 1. pp. 140-146. IEEE Trans. on Ind. Appl. January/February 1988. Vol. 24. No. 1. pp. 151-159. C.G. Wang, T.A. Lipo, D.W. Novotny
1986-011 011 Efficient operation of surface mounted PM synchronous motor drives IEEE-IAS Conf. Rec. 1986. Vol. 1. pp. 806-813. IEEE Trans. on Ind. Appl. November/December 1987. Vol. 23. No. 6. pp. 1048-1054. R.S. Colby, D.W. Novotny
1986-012 012 A graphical approach to AC drive classification IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. IA-23, NO. 6, NOVEMBER/DECEMBER 1987. D. Jarc, D.W. Novotny
1986-013 013 Selection of flux level in field oriented induction machine controllers with consideration of magnetic saturation effects In Proc. of IEEE-IAS Conf. Rec. 1986, Denver, pp. 124-131, and in IEEE Trans. on Ind. Appl., Vol. 1A-23, No. 2, March/April 1987, pp. 276-282. F.M.H Khater, R.D. Lorenz, D.W. Novotny, K. Tang
1986-015 015 Resonant DC link converters - a new concept in static power conversion IEEE-IAS Conf. Rec. Sept 28 - Oct 3, 1986. Part 1. pp. 648-650. IEEE Trans. on Ind. Appl. March/April 1989. Vol. 25. No. 2. pp. 314-325. D.M. Divan
1986-016 016 Performance of feed forward current regulators for field oriented inductino machine controllers In Proc. of IEEE-IAS Conf. Rec. 1986, Denver, pp. 99-105, and in IEEE Trans. on Ind. Appl., Vol. 1A-23, No. 4, July/August 1987, pp. 597-602. R.D. Lorenz, D.B. Larson
1986-017 017 Synthesis of a state variable motion controller for high performance field oriented induction machine drives In Proc. of IEEE-IAS Conf. Rec. 1986, Denver, pp. 80-85. R.D. Lorenz, M.O. Lucas
1986-018 018 Power conversion distribution system using a resonant high frequency AC link IEEE-IAS Conf. Rec. 1986. Vol. 1. pp. 533-541. IEEE Trans. on Ind. Appl. March/April 1988. Vol. 24. No. 24. pp. 288-300. P.K. Sood, T.A. Lipo
1987-001 001 A versatile power converter for high frequency link systems. APEC. 1987. pp. 249-256 IEEE Trans. on Power Elec. October 1988. Vol. 3. No. 4. pp. 383-390. P.K. Sood, T.A. Lipo, I.G. Hansen
1987-002 002 Magnetic equivalent circuit representation of electric machines Electric Machines & Power Systems. 1987. Vol. 12. No. 6. pp. 407-432. V. Ostovic
1987-003 003 Controlled single phase self-excited operation of induction generators Beijing Int'l Conference on Elect. Machines (BICEM). Book II. Aug 10-14, 1987. pp. 885-888. W. Hanguang, D.W. Novotny
1987-004 004 Pseudo-resonant full bridge DC/DC converter IEEE-PESC Conf. Rec. June 21-26, 1987. pp. 424-430. IEEE Trans. on Power Elect. October 1991. Vol. 6. No. 4. pp. 671-678. O.D. Patterson, D.M. Divan
1987-005 005 Delta modulation strategies for resonant link inverters IEEE-PESC Conf. Rec. June 21-26, 1987. pp. 271-278. IEEE Trans. on Power Elect. April 1990. Vol. 5. No. 2. pp. 220-228. M. Kheraluwala, D.M. Divan
1987-006 006 Efficienty considerations in PM synchronous motor drives Electric Energy Conf. (EECON). Barton, Australia. October 6-9, 1987. Vol. 1. pp. 286-291. R.S. COlby, R.F. Shiferl, D.W. Novotny
1987-007 007 Optimal utilization of induction machines in field oriented drives Department of Electrical and Computer Engineering, University of Wisconsin-Madison, May 1987. R.D. Lorenz, D.W. Novotny
1987-008 008 Power converter topologies for high performance motion control systems Conf. on Appl. Motion Control (CAMC). June 16-18, 1987. pp. 81-86. D.M. Divan
1987-009 009 Dynamic analysis and experimental evaluation of Delta modulators for field oriented AC machine current regulators In Proc. of IEEE-IAS Conf. Rec.1987, Atlanta, pp. 196-201, and in IEEE Trans. on Ind. Appl., Vol 26, No. 2, March/April 1990, pp. 296-301. R.D. Lorenz, D.M. Divan
1987-010 010 Characterization of power transistors under zero voltage switching IEEE-IAS Conf. Rec. October 18-23, 1987. Vol. 1. pp. 493-503. G. Skinbski, D.M. Divan
1987-011 011 Zero-switching loss inverters for high power applications IEEE-IAS Conf. Rec. October 18-23, 1987. Vol. 1. pp. 627-634. IEEE Trans. on Ind. Appl. July 1989. Vol. 25. No. 4. pp. 634-643. D.M. Divan, G. Skibinski
1987-012 012 A novel converter fed reluctance motor with high power density Electric Energy Conf. (EECON ). October 6-9 1987. Vol. 1. pp. 125-134. Symp. on Elect. Drives. Naples, Italy. 1987. pp. 315-321. L. Xu, T.A. Lipo
1987-013 013 Rectifier/inverter reactive component minimization IEEE-IAS Conf. Rec. October 18-23, 1987. Part 1. pp. 648-657. IEEE Trans. on Ind. Appl. March/April 1989. Vol. 25. No. 2. pp. 307-316. T.G. Habetler, D.M. Divan
1987-014 014 An extended Kalman filter approach to rotor time constant measurement in PWN induction motor drives IEEE-IAS Conf. Rec. 1987. Vol. 1. pp. 177-183.IEEE Trans. on Ind. Appl. January/February 1992. Vol. 28, No. 1. pp. 96-104. L.C. Zai, T.A. LIpo, C.L. DeMarco
1987-015 015 An efficiency optimizing permanent magnet synchronous motor drive IEEE-IAS Conf. Rec. 1987. Vol. 1. pp. 262-268.IEEE Trans. on Ind. Appl. May/June 1988. Vol. 24. No. 3. pp. 462-469. R.S. Colby, D.W. Novotny
1987-016 016 Field oriented controllers with rotor deep bar compensation circuits IEEE-IAS Conf. Rec. 1987. Vol. 1. pp. 142-149.IEEE Trans. on Ind. Appl. September/October 1992. Vol. 28. No. 4. pp. 1062-1071. R.W. DeDoncker
1987-017 017 Saturation effects in field oriented induction machines In Proc. of IEEE-IAS Conf. Rec.1987, Atlanta, pp. 150-155, and in IEEE Trans. on Ind. Appl., Vol 26, No. 2, March/April, 1990, pp. 283-289. R.D. Lorenz, D.W. Novotny
1987-018 018 Flux and torque decoupling control for field weakened operation of field oriented induction machines In Proc. of IEEE-IAS Conf. Rec.1987, Atlanta, pp. 132-141, and in IEEE Trans. on Ind. Appl., Vol 26, No. 2, March/April, 1990, pp. 290-295. R.D. Lorenz, D.B. Lawson
1987-019 019 A novel technique of rotor resistance estimation considering variation of mutual inductance IEEE-IAS Conf. Rec. 1987. Vol. 1. pp. 184-188. IEEE Trans. on Ind. Appl. July/Aug 1989. Vol. 25. No. 4. pp. 578-587. S.K. Sul
1987-020 020 Study of the generator/motor operation of induction machines in a high frequency link space power system Prepared for NASA-Lewis Research Center. T.A. Lipo, P.K. Sood
1987-021 021 Simulation of a four phase switched reluctance motor including the effects of mutual coupling Beijing International Conference on Electrical Machines (BICEM). Book I.Aug 10-14, 1987. pp. P-21 - P-27. Elect. Machines & Power Sys. 1989. Vol. 16. No. 4. pp. 281-299. J.C. Moreira, T.A. Lipo
1987-022 022 A novel method for evaluation of transient states in saturated electric machines IEEE-IAS Conf. Rec. 1987. Vol. 1. pp. 52-57. IEEE Trans. on Ind. Appl. January/February 1989. Vol. 25. No. 1. pp. 96-100. V. Ostovic
1987-023 023 Recent progress in the development of solid state AC motor drives Electric Energy Conf. and Instrumentation (EECON '87). October 6-9 1987. Vol. I. pp. 125-134. IEEE Trans. on Power Elec. April 1988. Vol. 3. No. 2. pp. 105-117. T.A. Lipo
1987-024 024 Design of a robust controller for direct field oriented control of an induction motor Electric Drives Conf. Rec. Sept 1987. pp. 137-143. F. Profumo, d. Zinger, T.A. Lipo
1987-025 025 The potential for high temperature superconducting AC and DC motors Electric Machines & Power Systems. 1988. Vol. 13. No 6. pp. 373-385. T.A. Lipo
1987-026 026 High temperature superconductors in electric power equipment? Electric Machines & Power Systems. 1987. Vol. 13. No. 5. pp. 329-345. R.W. DeDoncker, D.W. Novotny
1988-001 001 Exact inverter waveform analysis using Z-transform techniques In Proc. of IEEE-PESC Conference1988, and in IEEE Trans. on Power Electronics, Vol 5, No. 3, July1990, pp. 284-293. R.D. Lorenz, R.A. Cook
1988-002 002 A stator flux oriented induction motor drive IEEE-PESC Conf. Rec. April 11-14, 1988. Vol. 2. pp. 870-876. X Xu, R.W. DeDoncker, D.W. Novotny
1988-003 003 An improved model for saturated salient pole synchronous motors IEEE-IAS Conf. Rec. 1988. Vol. 1. pp. 222-230.IEEE Trans. on Energy Conversion. March 1989. Vol. 4. No. 1. pp. 135-142. J.O. Ojo, T.A. Lipo
1988-004 004 Field oriented control of an induction machine in a high frequency link power system IEEE Trans. on Power Elect. October 1990. Vol. 5. No. 4. pp. 436-445. S.K. Sul, T.A. Lipo
1988-005 005 A direct field oriented controller for inductino machines using tapped stator windings IEEE-PESC Conf. Rec. April 11-14, 1988. Vol. 2. pp. 855-861. IEEE Trans. on Power Elect. October 1990. Vol. 5. No. 4. pp. 446-453. D. Zinger, F. Profumo, T.A. Lipo, D.W. Novotny
1988-006 006 Core loss in buried permanent magnet synchronous motors IEEE Trans. on Energy Conversion. June 1989. Vol. 4. No. 2. pp. 279-284. R. Schiferl, T.A Lipo
1988-007 007 A control systems perspective of field oriented control for AC servo drives Proceedings of the Controls Engineering Conf., June 6-11, 1988, Chicago, pp. XVIII-1 - XVIII-11. R.D. Lorenz, D.W. Novotny
1988-008 008 Electronic adjustable speed drive technology synopsis APEC Conf. Rec. December 3-4, 1986. pp. 10-?. R. Carpenter, T.A. Lipo
1988-009 009 Stator current programming of an interior permanent magnet synchronous motor WEMPEC Internal Report. A. Kumamoto
1988-010 010 Design and performance of a high frequency link induction motor drive operating at unity power factor IEEE-IAS Conf. Rec. Part 2. Oct 2-7, 1988. pp. 308-313. IEEE Trans. on Ind. Appl. May/June 1990. Vol. 26. No. 3. pp. 434-440. S.K. Sul, T.A. Lipo
1988-011 011 A digitally based voltage controller for correcting induction motor phase unbalance ICEM. Sept 12-14, 1988. Vol. 2. pp. 431-434. J. Oyama, F. Profumo, E. Muljadi, T.A. Lipo
1988-012 012 Power capability of salient pole permanent magnet synchronous motors in variable speed drive applications IEEE-IAS Conf. Rec. October 2-7, 1988. Part 1. pp. 23-31. IEEE Trans. on Ind. Appl. January/February 1990. Vol. 26. No. 2. pp. 212-221. R. Schiferl, T.A. Lipo
1988-013 013 An improved model of saturated induction machines IEEE-IAS Conf. Rec. October 1988. Part 1. pp. 222-230. IEEE Trans. on Ind. Appl. March/April 1990. Vol. 26. No. 2. pp. 212-221. J.O. Ojo, A. Consoli, T.A. Lipo
1988-014 014 Design and performance of a digitally based voltage controller for correcting phase unbalance in induction machines IEEE-IAS Conf. Rec. Part I. Oct 2-7, 1988. pp. 578-583. IEEE Trans. on Ind. Appl. May/June 1990. Vol. 26. No. 3. pp. 425-433. J. Oyama, F. Profumo, E. Muljadi, T.A. Lipo
1988-015 015 Single phase induction motor with an electronically controlled capacitor IEEE-IAS Conf. Rec. October 2-7, 1988. Part 1. pp. 169-174. T. Lettenmeier, D.W. Novotny, T.A. Lipo
1988-016 016 High frequency series resonant DC link power conversion IEEE-IAS Conf. Rec. Part I. Oct 2-7, 1988. pp. 772-779. IEEE Trans. on Ind. Appl. November/December 1992. Vol. 28. No. 6. pp. 1277-1285. Y. Murai, T.A. Lipo
1988-017 017 Analysis of a variable speed single-salient reluctance motor utilizing only two transistor switches IEEE-IAS Conf. Rec. October 2-7, 1988. Part 1. pp. 38-43. IEEE Trans. on Ind. Appl. March/April 1990. Vol. 26. No. 2. pp. 229-236. L. Xu, T.A. Lipo
1988-018 018 Efficiency considerations for low frequency operation of induction motors IEEE-IAS Conf. Rec. October 2-7, 1988. Vol. 1. pp. 91-96. S. Nishikata, D.W. Novotny
1988-019 019 Stator flux orientation control of induction machines in the field weakening region IEEE-IAS Conf. Rec. October 2-7, 1988. Vol. 1. pp. 437-443. X. Xu, R.W. DeDoncker, D.W. Novotny
1988-020 020 The universal field oriented controller. IEEE-IAS Conf. Rec. 1988. Vol. 1. pp. 450-456 IEEE Trans. on Ind. Appl. January/February 1994. Vol. 30. No. 1. pp. 92-100. R.W. DeDoncker, D.W. Novotny
1988-021 021 Performance characterization of a new 3 phase discrete pulse modulated current regulator IEEE-IAS Conf. Rec. October 2-7, 1988. Vol. 1. pp. 395-405. IEEE Trans. on Ind. Appl. November/December 1989. Vol. 25. No. 6. pp. 1139-1148. T.G. Habetler, D.M. Divan
1988-022 022 Efficiency-optimized flux trajectories for closed cycle operation of field oriented induction machine drives In Proc. of IEEE-IAS Conf. Rec. 1988,Pittsburgh, pp. 457-462, and in IEEE Trans. on Ind. Appl., May/June 1992, pp. 574-580. R.D. Lorenz, S.M. Yang
1988-023 023 High resolution velocity estimation for all digital, AC servo drives In Proc. of IEEE-IAS Conf. Rec. 1988,Pittsburgh,pp. 363-368,and in IEEE Trans. on Ind. Appl., July/Aug, 1991, Vol 27, No. 4, pp. 701-705. R.D. Lorenz, K. Van Patten
1988-024 024 Diodes as pseudo active elements in high frequency DC/DC converters IEEE-PESC Conf. Rec. April 11-14, 1988. Vol. 2. pp. 1024-1030. D.M. Divan
1988-025 025 Optimal discrete pulse modulation waveforms for resonant link inverters IEEE-PESC Conf. Rec. April 11-14, 1988. Vol. 2. pp. 567-5743 M. Kheraluwala, D.M. Divan
1988-026 026 Synthesis of optimal discrete pulse modulation waveforms through an integer quadratic program IEEE Int'l Symposium on Circuits and Systems. June 1988. pp. 1377-1380. C.L. DeMarco, D.M. Divan
1988-027 027 Characterization of GTOs for soft switching applications IEEE-IAS Conf. Rec. Oct 2-7,1988. Vol. 1. pp. 638-646. G.L. Skibinski, D.M. Divan
1988-028 028 A three-phase soft switched high power density DC/DC converter for high power applications IEEE-IAS Conf. Rec. October 2-7, 1988. Vol. 1. pp. 796-805. IEEE Trans. on Ind. Appl. January/February 1991. Vol. 29. No. 1. pp. 63-73. R.W. DeDoncker, D.M. Divan
1988-029 029 Design methodologies for soft switched inverters IEEE-IAS Conf. Rec. October 2-7, 1988. Vol. 1. pp. 758-766. IEEE Trans. on Ind. Appl. January/February 1993. Vol. 29. No. 1. pp. 126-135. D.M. Divan, G. Venkataramanan, R.W. DeDoncker
1988-030 030 Simulation of inverter fed induction motors including core losses IECON Conf. Rec. November 6-10, 1989. Vol. 1. pp. 232-237. M.R. Udayagiri, T.A. Lipo
1988-032 032 A simplified approach to continuous, on-line tuning of field oriented induction machine drives In Proc. of IEEE-IAS Conf. Rec. 1988,Pittsburgh, pp. 444-449, and in IEEE Trans. on Ind. Appl., May/June, 1990, Vol 26, No. 3, pp. 420-425. R.D. Lorenz, D.B. Lawson
1988-033 033 Resonant link converters: a new direction in solid state power conversion Int'l Conf. on Elect. Drives. Book I-The Plenary Session. Poiana-Brasov, Romania. September 20-22, 1988. Tenth paper, (pp. no. 87-97). T.A. Lipo
1988-034 034 Induction motor application considerations for adjustable speed drives EPRI Workshop on Adjustable Speed Drive Motors. Aug 23-24, 1988. T.A. Lipo, D.W. Novotny
1988-035 035 Design and test of bidirectional speed and torque control of induction machines operation from high fequency link converter Department of Electrical and Computer Engineering, University of Wisconsin-Madison, August 1988. T.A. Lipo, S. Sul
1989-001 001 Measurement and computation of starting torque pulsations of salient pole synchronous motors IEEE Trans. on Energy Conversion. March 1990. Vol 5. No 1. pp. 176-182. J.O. Ojo, V. Ostovic, J.C. White, T.A. Lipo
1989-002 002 Combining drives of different bandwidths to meet process objectives Proceedings of the Controls Engineering Conf., May 23-25, 1989, Chicago. R.D. Lorenz, P.B. Schmidt
1989-003 003 Power electronics technology in the U.S., Japan and Europe EPRI sponsored report. D.M. Divan
1989-004 004 Angle controlled current regulated rectifiers for AC/AC converters IEEE-PESC Conf. Rec. June 26-29, 1989. pp. 704-710. IEEE Trans. on Power Elect. July 1991. Vol. 6. No. 3. pp. 463-469. T.G. Habetler, D.M. Divan
1989-005 005 Acoustic noise reduction in sinusoidal PWM drives using a randomly modulated carrier IEEE-PESC Conf. Rec. June 26-29, 1989. pp. 665-671. IEEE Trans. on Power Elect. July 1991. Vol. 6. No. 3. pp. 356-363. T.G. Habetler, D.M. Divan
1989-006 006 A new field oriented controller utilizing spatial position measurement of rotor end ring current IEEE-PESC Conf. Rec. 1989. Vol. 1. pp. 295-300. V. Blasko, T.A. Lipo, J.C. Moreira
1989-007 007 Discrete pulse modulation strategies for high frequency inverter systems IEEE-PESC Conf. Rec. June 26 -29, 1989. pp. 1013-1020. IEEE Trans. on Power Elect. July 1993. Vol. 8. No. 3. pp. 279-287. G. Venkataramanan, D.M. Divan, T.M. Jahns
1989-008 008 Performance testing of a high frequency link converter for space station power distribution systems IEEE Intersociety Energy Conveion Engineering Conf. (IECEC). Aug 6-11, 1989. Vol. 1. No. 899362. pp. 617-623. S.K. Sul, I. Alan, T.A. Lipo
1989-009 009 Feasibility study of a converter optimized induction motor EPRI RP2624-02. T.A. Lipo, H.A. Toliyat
1989-010 010 A new topology for single phase UPS systems IEEE-IAS Conf. Rec. October 1-5, 1989. Part 1. pp. 931-936. D.M. Divan
1989-011 011 Active power filters using resonant pole inverters IEEE-IAS Conf. Rec. October 1-5, 1989. Part 1. pp. 967-973. IEEE Trans. on Ind. Appl. November/December 1992. Vol. 28. No. 6. pp. 1269-1276. B.S. Acharya, R.W. Gasoigne, D.M. Divan
1989-012 012 Control strategies for direct torque control using discrete pulse modulation IEEE-IAS Conf. Rec. 1989. pp. 514-522. IEEE Trans. on Ind. Appl. September/October 1991. Vol. 27. No. 5. pp. 893-901. T.G. Habetler, D.M. Divan
1989-013 013 Bus utilization of discrete CRPWM inverters for field oriented drives IEEE-IAS Conf. Rec. 1989. Vol. 1. pp. 362-367. IEEE Trans. on Ind. Appl. November/December 1991. Vol. 27. No. 6. pp. 1128-1135. X. Xu, D.W. Novotny
1989-014 014 A synchronized resonant DC link converter for soft-switched PWM IEEE-IAS Conf. Rec. October 1-5, 1989. Part 1. pp. 1037-1044. IEEE Trans. on Ind. Appl. September/October 1993. Vol. 29. No. 3. pp. 940-948. L. Malesani, P. Tenti, D.M. Divan, V. Toigo
1989-015 015 Simple efficiency maximizer for an adjustable frequency induction motor drive IEEE Trans. on Ind. Appl. September/October 1991. Vol. 27. No. 5. pp. 940-946. J.C. Moreira, V. Blasko, T.A. Lipo
1989-016 016 Current pulse control of high frequency series resonant DC link power converter IEEE-IAS Conf. Rec. October 1989. Part 1. pp. 1023-1030. Y. Murai, S. Mochizuki, P. Caldeira, T.A. Lipo
1989-017 017 Field oriented control of synchronous machines Journal of IETE (India). September/October 1990. Vol 37. No 1. pp. 46-56. D.W. Novotny, P.L. Jansen
1989-018 018 AC induction servo sizing for motion control applications via loss minimizing real-time flux control In Proc. of IEEE-IAS Conf. Rec. 1989, San Diego, Oct. 1-5, pp. 612-617, in IEEE Trans. on Ind. Appl., Vol. 0 No. 0 May/June 1992, pp.589-593. R.D. Lorenz, S.M. Yang
1989-019 019 Stability and harmonics in thyristor controlled reaction. PICA Conf. Rec. 1989. pp. 372-378 IEEE Trans. on Power Delivery. April 1990. Vol 5. No 5. pp. 1175-1181. L.J. Bohmann, R.H. Lasseter
1989-020 020 Synchronized motion control for process automation In Proc. of IEEE-IAS Conf. Rec. 1989, San Diego, Oct. 1-5, pp. 1693-1698. R.D. Lorenz, P.B. Schmidt
1989-021 021 Using induction motor stator windings to extract speed information IEEE-IAS Conf. Rec. 1989. Part 1. pp. 213-218. D.S. Zinger, T.A. Lipo, D.W. Novotny
1989-022 022 Numerical solutions and mapping of electrostatic fields using the Apple MacIntosh Computer IEEE Trans. on Ed. February 1990. Vol. 33. No. 1. pp. 104-110. F.G. Stremler, S.A. Klein, F. Luo, Y. Liao
1989-023 023 Harmonic interaction in thyristor controller reactor circuits IEEE Trans. on Power Delivery. July 1989. Vol 4. No 3. pp. 1919-1926. L.J. Bohmann, R.H. Lasseter
1989-024 024 Implementation of a controlled rectifier using AC-AC matrix converter theory IEEE-PESC Conf. Rec. June 26-29, 1989. pp. 353-359. IEEE Trans. on Power Elec. January 1992. Vol. 7. No. 1. pp. 240-250. D.G. Holmes, T.A. Lipo
1989-027 027 Control strategies for direct torque control using discrete pulse modulation IEEE Trans on Ind. Appl. Vol. 27, No.5, Sept-Oct. 1991. pp. 893-901. T. Habetler, D.M. Divan
1989-028 028 New control strategy for matrix converter IEEE-PESC Conf. Rec. June 26-29, 1989. pp. 360-367. J. Oyama, T. Higuchi, E. Yamada, T. Koga, T.A. Lipo
1989-029 029 Transient model of a doubly excited reluctance motor IEEE Trans. on Energy Conversion. March 1991. Vol 6. No 1. pp. 126-133. L. Xu, F. Liang, T.A. Lipo
1990-001 001 Quasi real time simulation of power electronic systems IEEE-APEC. March 11-16, 1990. pp. 634-640. L. Rausch, R. DeDoncker, D.M. Divan, R.D. Lorenz
1990-002 002 Design and control of a series resonant DC link power converter drive IPEC. April 2-6, 1990. Vol. 1. pp. 397-404. P. Caldeira, T.A. Lipo, Y. Murai, S. Mochizuki
1990-003 003 A new energy recovery scheme for doubly fed, variable speed induction motor drives IEEE Int'l Conf. on Appl. of Ind. Elect. Sys. May 13-17, 1990. pp. 106-110. IEEE Trans. on Ind. Appl. July/August 1991. Vol. 27. No. 4. pp. 728-733. F. Fan, S. Ji, T.A. Lipo
1990-004 004 Design considerations for high power density DC/DC converters. High Freq Power Conversion (HFPC) Conf. Rec. May 1990. pp. 324-335. M. Kheraluwala, D.M. Divan, E. Bauman
1990-005 005 A dual active bridge SMPS using synchronous rectifiers High Freq. Power Conversion (HFPC) Conf. Rec. May 1990. pp. 336-346. H.L. Wiegman, G. Venkataramanan, M.H. Kheraluwala, D.M. Divan
1990-006 006 Control strategies for synchronized resonant link inverters IPEC. April 2-6, 1990. Vol. 1. pp. 338-345. D.M. Divan, G. Venkataramanan, L. Malesani, V. Toigo
1990-007 007 The electric machines and power electronics laboratory modernization at the University of Wisconsin Department of Electrical and Computer Engineering, University of Wisconsin-Madison, March 1990. D.W. Novotny, R.D. Lorenz, T.A. Lipo, D.M. Divan
1990-008 008 A new direct field oriented controller employing rotor end ring current detection IEEE-PESC Conf. Rec. 1990. Vol. 2. pp. 599-605. IEEE Trans. on Power Elect. November 1994. Vol 9. No 9. pp. 638-645. Y. Blakso, T. Matsuo, J.C. Moreira, T.A. Lipo
1990-009 009 A new method for rotor time constant tuning in indirect field oriented control IEEE-PESC Conf. Rec. 1990. Vol. 2. pp. 573-580. IEEE Trans. on Power Elect. October 1993. Vol. 8. No. 4. pp. 626-631. J.C. Moreira, T.A. Lipo
1990-010 010 A method to extend the low frequency operation of load commutated inverters IEEE-PESC Conf. Rec. June 10-15, 1990. Vol. 1. pp. 461-468. H.L. Hess, D.M. Divan
1990-011 011 Design considerations for high power high frequency transformers IEEE-PESC Conf. Rec. June 10-15, 1990. Vol. 2. pp. 734-742. M.H. Kheraluwala, D.W. Novotny, D.M. Divan
1990-012 012 Discrete time integral sliding mode control for discrete pulse modulated converters IEEE-PESC Conf. Rec. June 10-15, 1990. Vol. 1. pp. 67-73. G. Venkataramanan, D.M. Divan
1990-013 013 Utilization of the series resonant DC link as a conditioning system for SMES IEEE-PESC Conf. Rec. June 10-15, 1990. Vol. I. pp. 266-272. IEEE Trans. on Power Elec. July 1992. Vol. 7. No. 3. pp. 506-513. K.W. Marschke, P. Caldeira, T.A. Lipo
1990-014 014 Power control applications on a superconducting LVdc mesh IEEE Trans. on Power Delivery. July 1991. Vol 6. No 3. pp. 1282-1288. B.K. Johnson, R.H. Lasseter, R. Adapa
1990-015 015 Frequency dependence of time harmonic losses in induction machines ICEM. Aug 13-15, 1990. Vol. 1. pp. 233-238. D.W. Novotny, S.A. Naser, D. Maly, B. Jeftenic
1990-016 016 d-q Analysis of a variable speed doubly excited reluctance motor Electric Machines and Power Systems. 1991. Vol 19. No 2. pp. 125-138. F. Liang, L. Xu, T.A. Lipo
1990-017 017 Calculations of electromagnetic fields including end effect using fourier transform method ICEM. Aug 13-15, 1990. Vol. 2. pp. 751-756. A. Fahim, T.A. Lipo
1990-018 018 A low loss permanent magnet brushless DC motor utilizing tape wound amorphous iron IEEE-IAS Conf. Rec. Oct 7-12, 1990. Part I. IEEE Trans. on Ind. Appl. May/June 1992. Vol. 28. No. 3. pp. 646-651. C.C. Jensen, T.A. Lipo, F. Profumo
1990-019 019 Utilization of the series resonant DC link as a DC motor drive IEEE-IAS Conf. Rec. October 7-12, 1990. Part 2. pp. 1208-1214. P. Caldeira, K.W. Marschke, T.A. Lipo, Y. Murai
1990-020 020 Modelling of saturated AC machines including airgap flux harmonic components IEEE-IAS Conf. Rec. October 7-12, 1990. Part 1. pp. 37-44. IEEE Trans. on Ind. Appl. March/April 1992. Vol. 28. No. 2. pp. 343-349. J. Moreira, T.A. Lipo
1990-021 021 Vector control of synchronous reluctance motor including saturation and iron loss IEEE-IAS Conf. Rec. 1990. Vol. 1. pp. 359-364. IEEE Trans. on Ind. Appl. September/October 1991. Vol. 27. No. 5. pp. 977-985. L. Xu, X. Xu, D.W. Novotny, T.A. Lipo
1990-022 022 Implementation of direct stator flux orientation control on a versatile DSP based system IEEE-IAS Conf. Rec. 1990. Vol. 1. pp. 404-409. IEEE Trans. on Ind. Appl. July/August 1991. Vol. 27. No. 4. pp. 694-700. X. Xu, D.W. Novotny
1990-023 023 A Stator Flux-Oriented Voltage Source Variable-Speed Drive Based on DC Link Measurement IEEE-IAS Conf. Rec. 1990. pp. 410-415. IEEE Trans. on Ind. Appl. September/October 1991. Vol. 27. No. 5. pp. 962-969. Y. Xue, X Xu, T.G. Habetler, D.M. Divan
1990-024 024 A five phase reluctance motor with high specific torque IEEE-IAS Conf. Rec. October 7-12, 1990. Part 1. pp. 207-213. IEEE Trans. on Ind. Appl. May/June 1992. Vol. 28. No. 3. pp. 659-667. H. Toliyat, L. Xu, T.A. Lipo
1990-026 026 Performance characterization of a high power dual active bridge DC/DC converter IEEE-IAS Conf. Rec. October 7-12, 1990. Part 2. pp. 1267-1273. IEEE Trans. on Ind. Appl. November/December 1992. Vol. 28. No. 6. pp. 1294-1301. M.H. Kheraluwala, R.W. Gascoigne, D.W. Divan, E. Bauman
1990-028 028 Pulse width modulation with resonant DC link converters IEEE-IAS Conf. Rec. October 7-12, 1990. Part 2. pp. 984-990. IEEE Trans. on Ind. Appl. January/February 1993. Vol. 29. No. 1. pp. 113-120. G. Venkataramanan, D.M. Divan
1990-029 029 Unified characterization of GTO's under different modes of zero current switching IEEE-PESC Conf. Rec. 1991. pp. 444-452. IEEE Trans. on Power Elec. May 1994. Vol 9. No 3. pp. 338-345. A. Mertens, P. Caldeira, T.A. Lipo
1990-030 030 Application of non-linear observers for rotor position detection on an induction motor using machine voltages and currents In Proc. of IEEE-IAS Conf. Rec. 1990, Seattle, pp. 416-421. R.M. Cuzner, R.D. Lorenz
1990-031 031 A rotor flux error-based, adaptive tuning approach for feedforward field oriented induction machine drives In Proc. of IEEE-IAS Conf. Rec. 1990, Seattle, pp.589-594, in IEEE Trans. on Ind. Appl. January/February 1994, pp.101-110. K.T. Kung, R.D. Lorenz
1990-032 032 Design principles and implementation of acceleration feedback to improve performance of DC drives In IEEE-IAS Conf. Rec. 1990, Seattle, pp. 422-427, in IEEE Trans. on Ind. Appl., May/June 1992, pp. 594-599. P.B. Schmidt, R.D. Lorenz
1990-033 033 Considerations for low inertia ac drives in machine tool axis servo applications In Proc. of IEEE-IAS Conf. Rec. 1990, Seattle, pp.1551-1556, and in IEEE Trans. on Ind. Appl., March/April, 1991.Vol 27, No. 2, pp. 262-267. G.W. Younkin, W.D. McGlasson, R.D. Lorenz
1990-037 037 A high frequency resonant DC link inverter using IGBT's IPEC. April 2-6, 1990. Vol. 1. pp. 152-160. D.I.A. Mertens, D.M. Divan
1990-038 038 Analysis of a concentrated winding induction machine for adjustable speed drive applications. Part 1. Motor Analysis IEEE Trans. on Energy Conversion. Vol 6, No 4. December 1991. pp. 679-683. H.A. Toliyat, T.A. Lipo, J.C. White
1990-039 039 Analysis of a concentrated winding induction machine for adjustable speed drive applications. Part 2. Motor Deisgn and Performance IEEE Trans. on Energy Conversion. December 1991. Vol 6. No 4. pp. 684-692. H.A. Toliyat, T.A. Lipo, J.C. White
1990-040 040 Direct field orientation control using the third harmonic component of the stator voltage ICEM Conf. Rec. August 13-15, 1990. pp. 1237-1242. J.C. Moreira, T.A. Lipo
1990-041 041 Dynamic response of power conditioning systems for superconductive magnetic energy storage IEEE Trans. on Energy Conversion. Sept 1991. Vol 6. No 3. pp. 388-393. R.H. Lasseter, S.G. Jalali
1990-042 042 Power conditioning systems for superconductive magnetic energy storage IEEE Trans. on Energy Conversion. September 1991. Vol 6. No 3. pp. 381-387. R.H. Lasseter, S.G. Jalali
1990-043 043 High Speed, High Precision, Measurement Techniques for Ferrous Material Part Position Alignment Proc. of IEEE IAS Conf. 1990, pp. 1527-1532. C.M> Goshaw, R.D. Lorenz
1991-001 001 Novel reluctance machine concepts for variable speed drives Mediterranean Electrotechnical Conference, MELECON. May 1991. Vol. I. T.A. Lipo
1991-002 002 A novel single phase to three phase converter IEEE-APEC. March 1991. pp. 95-99. J. Nesbitt, C. Chen, D.M. Divan, D.W. Novotny
1991-003 003 Inverter topologies and control techniques for sinusoidal output power supplies IEEE-APEC 91. March 1991. pp. 81-87. D.M. Divan
1991-004 004 Equivalent circuit model for super conducting machine based on three dimensional field solution SM100 Conf. on Evolution and Modern Aspects of Synch. Machines. Aug 27-29, 1991. Part 3. pp. 803-805. A.A. Fahim, T.A. Lipo, D.W. Novotny
1991-005 005 Synchronous reluctance machines - a viable alternative for AC drives SM100 Conf. on Evolution and Modern Aspects of Synch. Machines. Aug 27-29, 1991. Part 2. pp. 475-479. T.A. Lipo
1991-006 006 Design considerations for high frequency co-axial winding power transformers IEEE-IAS Conf. Rec. Sept 28-Oct 4, 1991. Part 1. pp. 946-952. IEEE Trans. on Ind. Appl. March/April 1993. Vol. 29. No. 2. pp. 375-381. M.S. Rauls, D.W. Novotny, D.M. Divan
1991-007 007 Selection of the flux reference for induction machine drives in the field weakening region IEEE-IAS Conf. Rec. 1991. Vol. 1. pp. 361-367. IEEE Trans. on Ind. Appl. November/December 1992. Vol. 28. No. 6. pp. 1353-1358. X. Xu, D.W. Novotny
1991-008 008 Control of parallel connected inverters in stand-alone AC supply systems IEEE-IAS Conf. Rec. September 28-October 4, 1991. Vol 1. pp. 1003-1009. IEEE Trans. on Ind. Appl. January/February 1993. Vol. 29. No. 1. pp. 136-143. M. Chandorkar, D.M. Divan, R. Adapa
1991-009 009 Design and implementation of neural networks for digital current regulation of inverter drives IEEE-PESC Conf. Rec. 1990. Vol. II. pp. 573-580. M.R. Buhl, R.D. Lorenz
1991-010 010 Synchronous frame harmonic isolator using series active filter EPE/Fourth European Power Electronics Conference. Sept 3-6, 1991. Vol. 3. pp. 30-35. S. Bhattacharya, D.M. Divan, B. Banerjee
1991-011 011 A structure by which a recurrent neural network can approximate a nonlinear dynamic system In Proc. of IEEE-IJCNN Conf. Rec, Seattle, July 8-12, 1991, ppr no. 425. D.R. Seidl, R.D. Lorenz
1991-012 012 Implementation of a DSP-based, acceleration feedback robot controller: practical issues and design limits In Proc. of IEEE-IAS Conf. Rec 1991 , pp. 1425-1430. M.H. Moatemri, P.B. Schmidt, R.D. Lorenz
1991-013 013 Experimental identification of friction and its compensation in precise, position controlled mechanisms In Proc. of IEEE-IAS Conf. Rec 1991 , pp. 1400-1406, in IEEE Trans. on Ind. Appl., November/December, 1992, pp. 1392-1398. C.T. JOhnson, R.D. Lorenz
1991-014 014 Increasing the dynamic torque per ampere capability of induction machines In Proc. of IEEE-IAS Conf. Rec 1991 , pp. 14-20, IEEE Trans. on Ind. Appl. January/February 1994, pp.146-155. I.T. Wallace, R.D Lorenz, D.W. Novotny, D.M. Divan
1991-015 015 Dual-flow pulse trimming concept for a series resonant DC link power conversion IEEE-PESC Conf. Rec. June 24-27, 1991. pp. 254-260. Y. Murai, S.G. Aberyratne, T.A. Lipo, P. Caldeira
1991-016 016 Current peak limiting for a series resonant DC link power conversion using a saturable core EPE/ Fourth European Power Elect. Conf. September 3-6, 1991. Vol. 2. pp. 8-12. Y. Murai, S.G. Aberyratne, T.A. Lipo, P. Caldeira
1991-017 017 A simple and robust adaptive controller for detuning correction in field oriented induction machines In Proc. of IEEE-IAS Conf. Rec 1991 , pp. 397-403, in IEEE Trans. on Ind. Appl., November/December 1992, pp. 1359-1366. J.C. Moreira, K.T. Hung, T.A. Lipo, R.D. Lorenz
1991-018 018 Adjustable AC capacitor for a single phase induction motor IEEE-IAS Conf. Rec. Spet 28-Oct 4, 1991. Part 1. pp. 185-190. IEEE Trans. on Ind. Appl. May/June 1993. Vol. 29. No. 3. pp. 479-485. E. Muljadi, Y. Zhao, T.H. Liu, T.A. Lipo
1991-019 019 A strategy for improving reliability of field oriented controlled induction motor drives IEEE-IAS Conf. Rec. 1991. Part 1. pp. 449-455. IEEE Trans. on Ind. Appl. September/October 1993. Vol. 29. No. 5. pp. T.H. Liu, J.R. Fu, T.A. Lipo
1991-020 020 A modified C-dump converter for variable reluctance machines IEEE-IAS Conf. Rec. Sept 28-Oct 4, 1991. Part 1. pp. 886-891. IEEE Trans. on Ind. Appl. September/October 1992. Vol. 28. No. 5. pp. 1017-1022. A. Hava, V. Blasko, T.A. Lipo
1991-021 021 DQ Modeling of five phase synchronous reluctance machines including third harmonic of airgap MMF IEEE-IAS Conf. Rec. Sept 28-Oct 4, 1991. Part 1. pp. 231-237. IEEE Trans. on Ind. Appl. March/April 1998. Vol. 34. No. 2. pp. 332-339. H. Toliyat, M. Rahimian, T.A. Lipo
1991-022 022 Comparative evaluation of soft switching inverter topologies EPE/ Fourth European Conf. on Power Elect. and Appl. Sept 28-Oct 4, 1991. Vol. 2. pp. 13-18. D.M. Divan, G. Venkataramanan
1991-023 023 Switching characteristics of field controlled thyristors EPE-MADEP/Symposium on Power Semi-Conductor Devices. Vol 0, Joint Session. Sept 3-6, 1991. 0-220-0-225/ G. Venkataramanan, A. Mertens, H.C. Skudelny, H. Gruning
1991-024 024 Simple topologies for single phase AC line conditioning IEEE-IAS Conf. Rec. 1991. pp. 911-917. IEEE Trans on Ind. Appl. March/April 94. Vol. 30. No. 2. pp. 406-412. C. Chen, D.M. Divan
1991-025 025 Contactless power delivery system for mining applications In Proc. Of IEEE-IAS Conf. Rec. 1991, Dearborn, Michigan, pp1263-1269, and in EPRI 'Electricity in Mining' Workshop. Rec 1991, and IEEE Trans. on Ind. Appl., Jan/Feb 1995, pp. 27-35. K.W. Klontz, D.M. Divan, D.W. Novotny, R.D. Lorenz
1991-026 026 Harmonic interaction of power systems with static switching circuits IEEE-PESC Conf. Rec. June 24-27, 1991. pp. 330-337. S.G. Jalali, R.H. Lasseter
1991-027 027 GTO characterization for zero voltage switching applications IEEE-PESC Conf. Rec. June 24-27, 1991. pp. 437-443. G.L. Skinbinski, D.M Divan
1991-028 028 A ZVS dual resonant converter for battery charging applications IEEE-PESC Conf. Rec. June 24-27, 1991. pp. 202-208. H.L. Wiegman, D.M. Divan, D.W. Novotny, R. Mohan
1991-029 029 Input current shaping in brushless DC motor drives utilizing inverter current control IEE Conf. on Elect. Machines and Drives. Sept 1991. pp. 121-125. J. Skinner, T.A. Lipo
1991-030 030 Pulse-split concept in series resonant DC link power conversion for induction motor drives IEEE-IAS Conf. Rec. 1991. pp. 776-781. IEEE Trans. on Ind. Appl. January/February 1994. Vol 30. No 1. pp. 45-51. Y. Murai, H. Nakamura, T.A. Lipo, M.T. Aydemir
1991-031 031 The industrial consortium a format for University - Industry interaction Department of Electrical and Computer Engineering, University of Wisconsin-Madison, July 1991. D.W. Novotny, R.D. Lorenz, T.A. Lipo, D.M. Divan, R.H. Lasseter
1991-033 033 Status and trends in power converters for adjustable speed AC drives Int'l Conf. on Elect. Rotating Machines (ELROMA). January 1992. pp. 41-48. D.M. Divan, G. Venkataramanan, S. Battacharya
1991-034 034 Resonant links: a new family of converter topologies for solid state power conversion ABB Symposium on Power Semiconductor Devices and Circuits. Sept 26-27, 1991. pp. 291-315. T.A. Lipo, D.M. Divan
1992-001 001 Transient Analysis of Induction Machines Under Internal Faults Using Winding Functions Int'l Conf. on Electrical Rotating Machines (ELROMA). January 15-16, 1992. Vol III. pp. 1-13. S. Bhattacharya, T.A. Lipo, H.A. Toliyat, M.M. Rahimian
1992-002 002 A new doubly salient permanent magnet motor for adjustable speed drives SPEEDAM. May 19-21, 1992. pp. 415-420. Y. Liao, T.A. Lipo
1992-003 003 Design trade-offs in soft switching inverters. International Symposium in Power Electronics Department of Electrical and Computer Engineering, University of Wisconsin-Madison, March 1992. D.M. Divan, S. Bhattacharya, G. Luckjiff
1992-004 004 Design and performance of the field regulated reluctance machine IEEE-IAS Conf. Rec. 1992. Vol. 1. pp. 234-241. IEEE Trans. on Ind. Appl. September/October 1994. Vol 30. No 5. pp. 1185-1192. T.A. Lipo, J.D. Law, A. Chertok
1992-005 005 Use of neural networks to identify and compensate for friction in precision, position controlled mechanisms In Proc. of IEEE-IAS Conf. Rec 1992 , pp. 1937-1944. D.R. Seidl, T.L. Reineking, R.D. Lorenz
1992-006 006 Soft switched notching current source inverters IEEE-PESC. June 29-July 3, 1992. Vol II. pp. 1093-1097. G. Ledwich, E. Da Silva, T.A. Lipo
1992-007 007 Impact of control strategy on component ratings of series resonant DC link current converter ACEMP'92/Aegean Conference on Electrical Machines and Power Electronics. May 27-29, 1992. pp. 511-516. T.A. Lipo, M. Aydemir, E. da Silva, G. Ledwich
1992-008 008 Effect of saturation third harmonic on the performance of squirrel-cage induction machines ICEM/Int'l Conf. on Elect. Machines. Sept 15-17, 1992. Vol II. pp. 278-282. T.A. Lipo, Y. Liao
1992-009 009 New series resonant converter for variable reluctance motor drive IEEE-PESC Conf. Rec. June 29-July 3, 1992. Vol 2. pp. 833-838. S.S. Parks, T.A. Lipo
1992-010 010 Improving reliability of induction motor drives by means of fast acting current regulation 1st European Conference on Reliability, Standardization and Certification of Industrial Electric Drives. May 15-27, 1992. T.A. Lipo, J.R. Fu
1992-016 016 Analysis, design and experimental evaluation of a high power high frequency bidirectional DC/DC converter EPE 91/Fourth European Conf. on Power Elect. and Appl. Sept 1991. Vol 1. pp. 568-573. M. Kheraluwala, R. DeDoncker, D.M. Divan
1992-017 017 Status and trends in power converters for adjustable speed AC drives Int'l Conf. on Elect. Rotating Machines (ELROMA). January 1992. pp. 41-48. D.M. Divan, G. Venkataramanan, S. Bhattacharya
1992-018 018 Extending the low frequency operation of load commutated inverters with torque control techniques IEEE-IAS Conf. Rec. October4-9, 1992. Vol I. pp. 607-614. H. Hess, D.M. Divan
1992-019 019 Multi-turn high frequency co-axial winding power transformers IEEE-IAS Conf. Rec. October 1992. Vol II. pp. 1453-1457. IEEE Trans. on Ind. Appl. January/February 1995. Vol. 31. No. 1. pp. 112-118. M.S. Rauls, D.W. Novotny, D.M. Divan, R.R. Bacon, R.W. Gascoigne
1992-020 020 A unity power factor forward converter IEEE-IAS Conf. Rec. October 4-9, 1992. Vol I. pp. 666-672. D.M. Divan, C.C. Chen, G. Venkataramanan
1992-021 021 A single phase to three phase power converter for motor drive applications IEEE-IAS Conf. Rec. October 4-9, 1992. Vol I. pp. 639-646. C.C. Chen, D.M. Divan, D.W. Novotny
1992-022 022 Control of pulse width modulated resonant DC link inverter IEEE-IAS Conf. Rec. October 4-9, 1992. Vol I. pp. 737-743. G. Venkataramanan, D.M. Divan
1992-023 023 Improved performance voltage and current regulators using discrete pulse modulation IEEE-PESC Conf. Rec. June 29-July 3, 1992. Vol I. pp. 601-606. G. Venkataramanan, D.M. Divan
1992-024 024 Loss mechanisms in IGBTs under zero voltage switching IEEE-PESC Conf. Rec. June 29-July 3, 1992. Vol. 2. pp. 1011-1017. A. Kurnia, O.H. Stielau, G. Venkataramanan, D.M. Divan
1992-025 025 A new variable reluctance motor utilizing auxiliary commutation winding IEEE Trans. on Ind. Appl. March/April 1994. Vol 30. No 2. pp. 423-432. F. Liang, T.A. Lipo
1992-026 026 Control of a Polyphase Induction Generator/Induction Motor Power Conversion System Completely Isolated from the Utility IEEE Trans. on Ind. Appl. May/June 1994. Vol 30. No 3. pp. 636-647. I. Alan, T.A. Lipo
1992-027 027 Direct field orientation controller using the stator phase voltage third harmonic IEEE-IAS Conf. Rec. 1992. Vol. 1. pp. 508-514. IEEE Trans. on Ind. Appl. March/April 1994. Vol. 30. No. 2. pp. 441-447. J. Moreira, L. Kreindler, a. Testa, T.A. Lipo
1992-028 028 Pulse width modulated series resonant converter IEEE-IAS Conf. Rec. October 4-9, 1992. Vol I. pp. 744-749. E. da Silva, G. Ledwich, M. Aydemir, T.A. Lipo
1992-029 029 Verification of enhanced dynamic torque per ampere capability in saturated induction machines In Proc. of IEEE-IAS Conf. Rec. 1992, pp.40-47. and in IEEE Trans. on Ind. Appl., Sep/Oct 1994, pp.1193-1201. I.T. Wallace, R.D. Lorenz, D.W. Novotny, D.M. Divan
1992-030 030 The influence of winding capacitance on high frequency time harmonic losses in induction motors IEEE-IAS Conf. Rec. October 4-9, 1992. Vol I. pp. 33-39. D. Maly, D.W. Novotny, R.R. Bacon
1992-031 031 A physically insightful approach to the design and accuracy assessment of flux observers for field oriented induction machine drives In Proc. of IEEE-IAS Conf. Rec. 1992, pp. 570-577, and in IEEE Transactions on Industry Applications. Vol. 30. No. 1. January/February 1994. pp. 101-110. P.L. Jansen, R.D. Lorenz
1992-032 032 An integrated vehicle and electromagnetic propulsion unit for a high-speed material transport system IEEE-IAS Conf. Rec. October 4-9, 1992. Vol. 2. pp. 1945-1954. P.L. Jansen, L.J. Li, B. Werner, R.D. Lorenz
1992-033 033 High-performance LIM-based material transfer In Proc. of the 1992 NSF Design and Manf. Systems Conf. , Atlanta, Jan 8-10, 1992, pp. 1027-1030. R.D. Lorenz, N.A. Duffie, J.L. Sanders
1992-035 035 Unexpected instabilities due to bifurcation of switching times in a thyristor controlled reactor IEEE-PESC Conf. Rec. June 28-July 3, 1992. Vol I. pp. 546-552. R.H. Lasseter, S.G. Jalali, I. Dobson,
1992-036 036 Harmonic instabilities in advanced series compensators FACTS Conference II. EPRI TR-101784. December 1992. Section 1.4. 1-16. R.H. Lasseter, S.G. Jalali
1992-037 037 A novel permanent magnet motor with doubly salient structure IEEE IAS Conf. Rec. October 1992. Vol I. pp. 308-314. IEEE Trans. on Ind. Appl. September/October 1995. Vol. 31. No. 5. pp. 1069-1078. Y. Liao, F. Liang, T.A. Lipo
1992-038 038 Power conditioning interfaces for medium power photovoltaic systems ELROMA Conf. Rec. 1992. pp. 75-83. B.K. Johnson, M.C. Chandorkar
1992-039 039 Innovative inverter topology for concentrated winding PM motor drives IEEE-PESC Conf. Rec. 1992. Vol. 2. pp. 964-972. IEEE Trans. on Power Elec. March 1994. Vol 9. No 2. pp. 232-239. F. Caricchi, F. Crescimbini, T.A. Lipo, E. Santini
1992-040 040 Design of an active series/passive parallel harmonic filter for ASD loads at a wastewater treatment plant Department of Electrical and Computer Engineering, University of Wisconsin-Madison, June 1992. D.M. Divan, S. Bhattacharya, R. Zavadil, B. Banerjee, D. Pileggi, D. Atwood
1992-041 041 High temperature superconducting DC networks IEEE Trans. on Appl. Superconductivity. September 1994. Vol 4. No 3. pp. 115-120. R.H. Lasseter, F.L. Alvarado, D.M. Divan, H. Singh, M.C. Chandorkar, B.K. Johnson, R. Adapa
1992-042 042 Expandable multiterminal DC systems based on voltage droop IEEE Trans. on Power Delivery. October 1993. Vol 8. No 4. pp. 1926-1932. R.H. Lasseter, F.L. Alvarado, B.K. Johnson, R. Adapa
1992-043 043 Switching time bifurcations in a thyristor controlled reactor IEEE Transactions on Circuits and Systems. March 1996. Vol. 43. No. 3. pp. 209-218. I. Dobson, R.H. Lasseter, S. Jalali, G. Venkataramanan
1993-001 001 An electric vehicle charging system with 'universal' inductive interface In Proc. of Conference Record of the IEEE-IAS, PCC Yokohama Technical Conference, pp 227-232, Japan, April, 1993. K.W. Klontz, A. Esser, R.R. Bacon, D.M. Divan, D.W. Novotny, R.D. Lorenz
1993-002 002 Analysis of induction motor with voltage control by symmetrically triggered thyristors using quasi-rotating reference frame IMACS TCI-93. July 7-9, 1993. pp. 13-21. N.H. Kutkut, H. Cherradi, T.A. Lipo
1993-003 003 Impact of IGBT behavior on design optimization of soft switching inverter topologies IEEE-IAS Conf. Rec. Oct 4-9, 1993. Vol II. pp. 807-813. IEEE Trans. on Ind. Appl. March/April 1995. Vol. 31. No. 2. pp. 280-286. A. Kurnia, H. Cherradi, D.M. Divan
1993-004 004 Transient performance of autonomous self-excited induction generator system IMACS-TCI 93 Simulation Conf. July 7-9, 1993. pp. 165-169. K.S. Sakkoury, D.W. Novotny, F.I. Ahmed, F.M.H. Khater
1993-006 006 Observer-based direct field orientation analysis and comparison of alternative methods In Proc. of IEEE-IAS Conf. Rec 1993, pp. 536-543, and in IEEE Trans. on Ind. Appl., July/August 1994, pp.945-953. P.L. Jansen, R.D. Lorenz, D.W. Novotny
1993-007 007 Design Integration of a 200 KW GTO RDCL Converter IEEE-IAS Conf. Rec. Oct 2-8, 1993. Vol II. pp. 1029-1040. EPE Conf. Rec. 1993. Vol. 3. pp. 98-105. G.L. Skibinski, D.M. Divan
1993-008 008 Selection of the pole number of induction machines for variable speed applications IEEE-IAS Conf. Rec. October 1993. Vol I. pp. 367-374. IEEE Trans. on Ind. Appl. March/April 1995. Vol. 31. No. 2. pp. 304-310. F. Liang, D.W. Novotny, R. Fei, X. Xu
1993-009 009 Force commutated three-level boost type rectifier IEEE-IAS Conf. Rec. October 1993. Vol II. pp. 771-777. IEEE Trans. on Ind. Appl. January/February 1995. Vol. 31. No. 1. pp. 155-161. Y. Zhao, Y. Li, T.A. Lipo
1993-010 010 A doubly salient doubly excited variable reluctance motor IEEE-IAS Conf. Rec. October 1993. Vol I. pp. 137-143. IEEE Trans. on Ind. Appl. January/February 1995. Vol. 31. No. 1. pp. 99-106. H.Y. Li, Y. Liang, Y. Zhao, T.A. Lipo
1993-011 011 Analysis of competing topologies of linear induction machines for high speed material transport systems IEEE-IAS Annual Meeting. Vol I. Oct 2-8, 1993. pp. 274-281, and in IEEE Trans. on Ind. Appl., July/August 1995, pp 925-932. P.L. Jansen, L.J. Li, R.D. Lorenz
1993-013 013 Neural network compensation of gear backlash hysteresis in position-controlled mechanisms In Proc. of IEEE-IAS Conf. Rec 1993, pp.2027-2034, in IEEE Trans. on Ind. Appl. November/December 1995, pp.1475-1483.11 D.R. Seidl, S.L. Lan, J.A. Putnam, R.D. Lorenz
1993-014 014 Accuracy limitations of velocity and flux estimation in direct field oriented induction machines In Proc. of 5th European Power Electronics (EPE) Conf. Rec., Brighton, UK, Vol. 4, pp 312-318, September 13-16, 1993. P.L. Jansen, R.D. Lorenz
1993-015 015 Observer-based direct field orientation for both zero and very high speed operation In Proc. of 1993 IEEE PCC-Yokohama Technical Conference, Japan, April 1993, pp. 432-437, and in IEEE, Ind. Appl. Society Magazine, Vol. 1, No. 4, July/Aug. 1995, pp 7-13. P.L. Jansen, C.O. Thompson, R.D. Lorenz
1993-016 016 A Review of Developments in Current Source Inverter Drives Department of Electrical and Computer Engineering, University of Wisconsin-Madison, May 1993. H.L. Hess
1993-017 017 Converter selection for electric vehicle charger systems with a high-frequency high-power link IEEE-PESC. June 20-24, 1993. pp. 885-861. K.W. Klontz, A. Esser, P.J. Wolfs, D.M. Divan
1993-018 018 Sizing and optimal design of doubly salient permanent magnet motors IEE 6th Int. Conf. on Elec. Machines and Drives. Sept. 8-10, 1993. pp. 452-456. Y. Liao, T.A. Lipo
1993-019 019 A permanent magnet AC machine structure with true field weakening capability IEEE Int'l Symposium on Ind. Elect. June 1-3, 1993. pp. 19-24. A. Shakal, Y. Liao, T.A. Lipo
1993-020 020 An improved full bridge zero-voltage switching PWM converter using a two inductor rectifier IEEE-IAS Conf. Rec. Oct 2-8, 1993. Part II. pp. 1065-1072. IEEE Trans. on Ind. Appl. January/February 1995. Vol. 31. No. 1. pp. 119-126. N.H. Kutkut, D.M. Divan, R.W. Gascoigne
1993-021 021 Sensorless synchronous reluctance motor drive using the stator phase voltage third harmonic IEEE-IAS Conf. Rec. 1993. Vol. 1. pp. 679-686. IEEE Trans. on Ind. Appl. March/April 1994. Vol 30. No 2. pp. 441-447. L. Kreindler, A. Testa, T.A. Lipo
1993-022 022 New ZCS resonant power converter topologies for variable reluctance machine drives IEEE-PESC. June 20-24, 1993. pp. 432-439. A. Hava, J.B. Wacknov, T.A. Lipo
1993-023 023 Field oriented control of synchronous reluctance motor IEEE-PESC Conf. Rec. 1993. pp. 425-431. T. Matsuo, T.A. Lipo
1993-024 024 Electromagnetic model for evaluation of flux harmonics and resulting vibrations in induction motors IEE 6th Int. Conf. on Electrical Machines and Drives. Sept 8-10, 1993. pp. 540-545. A.A. Fahim, T.A. Lipo, C.J. Slavic
1993-025 025 Control techniques for dual current source GTO inverters Power Conversion Conf. Rec. 1993. pp. 659-665. IEEE Trans on Ind. Appl. January/February 1995. Vol 31. No 1. pp. 134-140. M.C. Chandorkar, D.M. Divan, R.H. Lasseter
1993-026 026 Influence of current wave shape on motoring performance of the slotless permanent magnet machine torus IEE 6th Int. Conf. on Elect. Machines and Drives, Sept. 8-10, 1993. pp. 376-380. Z. Dostal, T.A. Lipo, B.J. Chalmers
1993-027 027 An industrial power distribution system featuring UPS properties IEEE-PESC Conf. Rec. June 20-24, 1993. pp. 759-765. B.K. Johnson, R.H. Lasseter
1993-032 032 Quasi current resonant DC link AC/AC converter IEEE Trans. on Power Elec. November 1994. Vol 9. No 6. pp. 594-600. H. Nakamura, Y. Murai, T.A. Lipo
1993-033 033 Elimination of discrete position sensor for synchronous reluctance motor IEEE-PESC Conf. Rec. 1993. pp. 440-445. M.S. Arefeen, M. Ehsani, T.A. Lipo
1993-034 034 DC link notching current inverter with soft commutation IEEE-PESC Conf. Rec. June 1993. E. Da Silva, G. Ledwich, T.A. Lipo, C.B. Jocabina
1993-035 035 Transient behavior comparison of saturated induction machine models IMACS-TCI-93 Computational Aspects of Electromechanical Energy Converters and Drives. July 7-9, 1993. pp. 577-580. M. Osama, K. Sakkoury, T.A. Lipo
1993-036 036 Rotor design optimization of synchronous reluctance machine IEEE Trans. on Energy Conversion. June 1994. Vol 9. No 2. pp. 359-365. T. Matsuo, T.A. Lipo
1993-037 037 A strategy to isolate the switching device fault of a current regulated motor drive IEEE-IAS Conf. Rec. Oct 2-8, 1993. Vol II. pp. 1015-1020. Electric Machines & Power Systems. December 1996. Vol. 24. No. 8. pp. 911-920. J.R. Fu, T.A. Lipo
1993-038 038 Series compensated PWM inverter with battery supply applied to an isolated induction generator IEEE-IAS Conf. Rec. 1993. Vol. 2. pp. 1392-1400. IEEE Trans. on Ind. Appl. July/August 1994. Vol 30. No 4. pp. 1073-1082. E. Muljadi, T.A. Lipo
1993-039 039 Disturbance free operation of a multiphase current regulated motor drive with an opened phase IEEE-IAS Conf. Rec. 1993. Vol. 1. pp. 637-644. IEEE Trans.on Ind. Appl. September/October 1994. Vol 30. No 5. pp. 1267-1274. J.R. Fu, T.A. Lipo
1993-040 040 Current sensorless field oriented control of synchronous reluctance motor IEEE-IAS Conf. Rec. 1993. Vol. 1. pp. 672-678. T. Matsuo, T.A. Lipo
1993-041 041 A new approach to motor condition monitoring in induction motor drives IEEE-IAS Conf. Rec. 1993. Vol. 1. pp. 645-650. IEEE Trans. on Ind. Appl. July/August 1994. Vol 30. No 5. pp. 905-911. S. Chen, E. Zhong, T.A. Lipo
1993-042 042 A new SCR based induction motor drive with wide speed range IEEE-IAS Trans. November/December 1994. pp. 1648-1655. H. Hess, D.M. Divan
1993-043 043 System design issues for resonant DC link inverter based drives EPE 1993. 1993. Vol 5. pp. 182-187. G. Luckjiff, G. Venkataramanan, C. Chen, D.M. Divan
1993-044 044 Conductivity modulation in PIN diodes simulated using a highly flexible approach IEEE-IAS Conf. Rec. October 1993. Vol II. pp. 1196-1201. K. Kramer, W.N.G. Hitchon, D.M. Divan
1993-046 046 Design and Integration of a 200 kW GTO RDCL Converter EPE 1993. 1993. Vol 3. pp. 98-105. IEEE-IAS Conf. Rec. 1993. pp. 1029-1040. G. Skibinski, D.M. Divan
1993-047 047 Control and reduction of terminal voltage total harmonic distortion (THD) in a hybrid series active and parallel passive filter system IEEE-PESC Conf. Rec. June 20-24, 1993. pp. 779-786. S. Bhattacharya, B. Banerjee, D.M. Divan
1993-048 048 Design and construction of permanent magent axial flux synchronous generator X Congresso Chileno de Ingenieria Electrica. Nov 1993. IEMDC '97 pp MA1-4.1 to MA7-4.3 R. Wallace, T.A. Lipo, J. Tapia, L. Moran
1993-049 049 Indirect field oriented control of induction machine using a reactive power perturbation system IMACS-TCI-93 Computational Aspects of Electromechanical Energy Converters and Drives. July 7-9, 1993. pp. 403-407. C. Sun, X. Luo, T.A. Lipo
1993-050 050 Instabilities due to bifurcation of switching times in a thyristor controlled reactor IEEE-PESC Conf. Rec. June 1992. pp. 544-552. S.G. Jalali, I. Dobson, R.H. Lasseter
1993-051 051 Superconducting breakers and current transfer devices for use with a superconducting LVDC mesh IEEE Trans. on Appl. Superconductivity. December 1994. Vol. 4. no. 4. pp. 216-222. B.K. Johnson, R.H. Lasseter, F.L. Alvarado, R. Adapa
1993-052 052 An Industrial Power Distribution System Featuring UPS Properties 24th Annual IEEE Power Electronics Specialists Conference, 1993. PESC '93 Record, June 1993. B.K. Johnson, R.H. Lasseter
1993-053 053 A graphic interface for power system simulation 1993 Power Ind. Computer Appl. Conf. May 1993. pp. 269-276. J.C. Lee, R.H. Lasseter, J.F. Beetem
1993-054 054 A study of nonlinear harmonic interaction between a single phase line-commutated converter and a power system IEEE Trans. on Power Delivery. July 1994. Vol 9. No 3. pp. 1616-1624. S.G. Jalali, R.H. Lasseter
1993-055 055 High temperature superconducting DC networks Part II: the AC system and inverter interface EPRI Report - submitted to IEEE Appl.Superconducting Trans. F.L. Alvardado, R.H. Lasseter, D.M. Divan, H. Singh, B.K. Johnson, M.C. Chandorkar, R. Adapa
1993-056 056 TACs enhancements for the electromagnetic transient program PICA Conf. Rec. 1993. pp. 350-356. IEEE Trans. on Power Systems. May 1994. Vol 9. No 2. pp. 736-742. R.H. Lasseter, J. Zhon
1993-057 057 The effects of DC stator current offsets in torque controlled induction machines Department of Electrical and Computer Engineering, University of Wisconsin-Madison, May 1993. J. Wacknov
1993-058 058 An analysis of the accuracy of indirect shaft sensor for synchronised reluctance motor IEEE Trans. on Ind. Appl. September/October 1994. Vol 30. No 5. pp. 1202-1209. M.S. Arefeen, M. Ehsani, T.A. Lipo
1993-059 059 Multiple coupled circuit modeling of induction machines IEEE-IAS Conf. Rec. October 1993. Vol I. pp. 203-210. IEEE Trans. on Ind. Appl. March/April 1995. Vol. 31. No. 2. pp. 311-318. X. Luo, T.A. Lipo, Y. Liao, H. Toliyat, A. El-Antably
1993-060 060 Dynamic response of a thyristor controlled switched capacitor IEEE Trans. on Power Delivery. July 1994. Vol 9. No 3. pp. 1609-1615. S. Jalali, R.H. Lasseter, I. Dobson
1993-061 061 Analysis of concentrated winding induction machines for adjustable speed drive applications - experimental results IEEE Transactions on Energy Conversion, December 1994. H. Toliyat, T.A. Lipo
1993-062 062 Improvements in EMI performance of inverter-fed motor drives APEC Conf. Rec. 1994. pp. 608-614. E. Zhong, S. Chen, T.A. Lipo
1993-063 063 Current clample, modified series resonant DC - link power converter for a gerneral purpose induction motor drive IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 12, NO. 2, MARCH 1997. S. Abeyratne, T.A. Lipo
1994-001 001 Improvements in EMI performance of inverter-fed motor drives IEEE-APEC Conf. Rec. Orlando, FL. February 13-17, 1994. pp. 608-614. E. Zhong, S. Chen, T.A. Lipo
1994-002 002 A PWM high frequency series resonant dc link converter and its utilization as a dc motor drive IEEE-IAS Annual Meeting. October 2-7, 1994. E.R.C. da Silva, G. Ledwich, M.T. Aydemir, T.A. Lipo
1994-003 003 Motion control with induction motors IEEE Proceedings Special Issue on Power Electronics and Motion Control, Vol 82, No. 8, pp. 1215-1240, August, 1994. R.D. Lorenz, T.A. Lipo, D.W. Novotny
1994-004 004 Control of distributed UPS systems IEEE-PESC. June 20-25, 1994. pp. 197-204. M. Chandorkar, D. Divan, B. Banerjee
1994-005 005 Analysis and modeling of five phase converters for adjustable speed drive applications. European Power Elect Conf. Brighton, England. September 1993. pp. 194-199. H.A. Toliyat, M.M. Rahimian, T.A. Lipo
1994-006 006 Sensorless synchronous motor drive for use on commercial transport planes IEEE-IAS Conf. Rec. October 2-7, 1994. pp. 553-559. IEEE Trans. on Ind. Appl. July/August 1995. Vol. 31. No. 4. pp. 850-859. P. Mezs, F. Nozari, A. Julian, C. SUn, T.A. Lipo
1994-007 007 A new induction machine model for analysis of eccentric rotor magnetic pull SPEEDAM Conf. June 7-9, 1994. M.O.E. Mohamed, T.A. Lipo
1994-008 008 A hybrid inverter/cyclconverter-based variable-speed three-phase induction motor drive for single-phase inputs IEEE-APEC Conf. Rec. February 13-17, 1994. pp. 514-520. IEEE Trans. on Ind. Appl. May/June 1995. Vol. 31. No. 3. pp. 630-635. C. Chen, D.M. Divan, D.W. Novotny
1994-009 009 A Novel Doubly Salient Permanent Magnet Generator IEEE-IAS Conf. Rec. October 2-7, 1994. pp. 9-15. B. Sarlioglu, Y. Zhao, T.A. Lipo
1994-010 010 Current clamped, PWM, quasi-resonant dc link series resonant converter IEEE-IAS Conf. Rec. October 2-7, 1994. pp. 820-826. S.G. Abeyratne, M.T. Aydemir, T.A. Lipo, Y. Murai
1994-011 011 A Permanent Magnet AC Machine Structure with True Field Weakening Capability IEEE Int'l Symposium on Ind. Elect. June 1-3, 1993. pp. 19-24. Electric Machines & Power Sys. July/August 1996. Vol. 24. No. 5. pp. 497-509. A.J. Shakal, Y. Liao, T.A. Lipo
1994-012 012 Series resonant dc link dual converter as a dc motor drive European Power Elect. Conf. September 1993. pp. 188-193. M. Yoshida, H. Soebagia, Y. Murai, T.A. Lipo
1994-014 014 Space Vector Pwm Control of Dual Three Phase Induction Machine Using Vector Space Decomposition IEEE-IAS Conf. Rec. October 2-7, 1994. pp. 742-749. IEEE Trans. on Ind. Appl. September/October 1995. Vol. 31. No. 5. pp. 1100-1109. Y. Zhao, T.A. Lipo
1994-015 015 A rotor lamination design for surface permanent magnet retention at high speeds In Proc. of IEEE-IAS Conf. Rec 1994, pp. 183-187 and in IEEE Trans. on Ind. Appl., March/April 1996, pp. 380 - 385. M.W. Degner, R. Van Maaren, A.A. Fahim, D.W. Novotny, R.D. Lorenz, C. Syverson
1994-016 016 Contactless underwater power delivery IEEE, Power Electronics Society, PESC 94 Technical Conference, June 20-24, 1994, Taipei, Taiwan, pp418-424, in IEEE Trans. on Ind. Appl. January/February, 1995, pp.27-35. B.J. Heeres, D.W. Novotny, D.M. Divan, R.D. Lorenz
1994-018 018 Control methodology for single inverter, parallel connected, dual induction motor drives for electric vehicles In Proc. of IEEE, PESC Conf., June 20-24, 1994, Taipei, Taiwan, pp. 987-991. P.M. Kelecy, R.D. Lorenz
1994-020 020 Transducerless position and velocity estimation in induction and salient ac machines In Proc. of IEEE-IAS Conf. Rec 1994, pp. 488-495, and in IEEE Trans. on Ind. Appl., Mar/Apr 1995, pp. 240-247. P.L. Jansen, R.D. Lorenz
1994-021 021 An actively cooled 120 kW coaxial winding transformer for fast charging electric vehicles IEEE-IAS Conf. Rec. October 1994. Vol 2. pp. 1045-1049. IEEE Trans. on Ind. Appl. November/December 1995. Vol. 31. No. 6. pp. 1257-1263. K.W. Klontz, D.M. Divan, D.W. Novotny
1994-022 022 Accuracy issues for parameter estimation of field oriented induction machine drives In Proc. of IEEE-IAS Conf. Rec 1994, pp. 593-600, and in IEEE Trans. on Ind. Appl., Jul/Aug 1995, pp. 795-801. D. Borgard, G. Olsson, R.D. Lorenz
1994-023 023 One-step optimal space vector PWM current regulation using a neural network IEEE-IAS Annual Meeting. Industrial Power Converter Committee. October 2-7, 1994. Denver, CO. pp. 867-874. D.R. Seidl, D.A. Kaiser, R.D. Lorenz
1994-024 024 Computer simulation & design optimization of IGBTs in soft-switching converters Proc. Sixth Int. Symp. Power Semiconductor Devices & IC's (ISPSD), May 31-June 2, 1994. pp. 105-109. I. Widjaja, A. Kurnia, D.M. Divan, K. Shenai
1994-026 026 Comparison of multilevel inverters for static var compensation IEEE-IAS Conf. Rec. October 2-7, 1994. Vol 2. pp. 921-928. C. Hochgraf, R. Lasseter, D.M. Divan, T.A. Lipo
1994-027 027 A novel low cost converter for variable reluctance motors International Conference on Electrical Machines, September 5-8, 1994. A. Ometto, A. Julian, T.A. Lipo
1994-028 028 Indirect rotor position sensor for synchronous reluctance motor at zero speed APEC. 1994. pp. 78-82. IEEE Trans. on Power Elect. Novemeber 1994. Vol 9. No 6. pp. 624-700. M.S. Arafeen, M. Ehsani, T.A. Lipo
1994-029 029 A PWM High Frequency Series Resonant DC Link Converter and Its Utilization as a DC Motor Drive Second Brazilian Power Electronics Conference. November 29-December 2, 1993. E.R.C. Da Silva, G. Ledwich, M.T. Aydemir, T.A. Lipo
1994-030 030 Rotor Position Detection Scheme for Synchronous Reluctance Motor Based on Current Measurements IEEE-IAS Conf. Rec. October 2-7, 1994. pp. 627-634. IEEE Trans. on Ind. Appl. July/August 1995. Vol. 31. No. 4. pp. 860-868. T. Matsuo, T.A. Lipo
1994-031 031 A passively clamped quasi resonant dc link inverter IEEE-IAS Conf. Rec. October 2-7, 1994. pp. 841-848. S. Chen, T.A. Lipo
1994-032 032 Current control of a three-level rectifier/inverter drive system IEEE-IAS Conf. Rec. October 2-7, 1994. pp. 859-866. M.C. Klarbunde, Y. Zhao, T.A. Lipo
1994-033 033 Novel architectures and control for distributed UPS systems IEEE-APEC. Conf. Rec. February 13-17, 1994. Vol 2. pp. 683-689. M. Chandorkar, D.M. Divan, Y. Hu, B. Banerjee
1994-034 034 Transient Analysis of Cage Induction Machines Under Stator, Rotor Bar, and End Ring Faults IEEE transactions on Energy Conversion, Vol. 10, No. 2, June 1995 Winding Functions, Stator Failure, Broken Rotor Bars and End-Rings, Induction Machines, Simulation An analysis method is developed for modeling of multi phase cage induction motors with asymmetry in the stator, arising due to an interturn fault resulting in a disconnection of one or more coils making up a portion of a stator phase winding and any distribution and number of rotor bar and end-ring failures. The approach, based on the winding functions, makes no assumption as to the necessity for sinusoidal MMF and therefore include all the space harmonics in the machine. Simulation and experimental results confirm the validity of the proposed method. H.A. Toliyat, T.A. Lipo
1994-035 035 Multiple coupled circuit modeling of synchronous reluctance machines IEEE-IAS Conf. Rec. 1994. pp. 281-289. X. Lou, A. El-Antably, T.A. Lipo
1994-036 036 Charge equalization for series connected battery strings IEEE-IAS Conf. Rec. October 2-7, 1994. Vol 2. pp. 1008-1015. IEEE Trans. on Ind. Appl. May/June 1995. Vol. 31. No. 3. pp. 562-568. N.H. Kutkut, D.M. Divan, D.W. Novotny
1994-037 037 The effect of bipolar transistor in the switching dynamics of IGBTs in Resonant Converter Applications IEEE Bipolar/BiCMOS Circuits and Technology Meeting (BCTM) Conf. Rec. 1994. pp. 135-138 H.H. Li, I. Widjaja, A. Kurnia, D. Divan, K. Shenai
1994-038 038 Scaling Constraints Imposed by Self-Heating in Submicron SOI MOSFETS IEEE Trans. on Electron Devices. Special Issue on Submicron Bipolar and Bicmos Technology. To be published. March 1995. D.A. Dallmann, K. Shenai
1994-039 039 Investigation of Self-Heating Effects in Submicron SOI MOSFETS International Society for Hybrid Microelectronics (ISHM) 1994 Symposium. November 15-17, 1994. D.A. Dallmann, K. Shenai
1994-040 040 Evaluation of self-heating in SOI CMOS ULSI International Reliability Workshop (IRN) '94 Workshop. October 16-19, 1994. D.A. Dallmann, K. Shenai
1994-041 041 Effect of Bipolar Turn-On on the Static Current-Voltage Characteristics of Scaled Vertical Power DMOSFETs IEEE Trans. on Elect. Devices. Vol. 42, No. 3. March 1995. K. Fischer, K. Shenai
1995-001 001 Utility interface issues for line connected PWM voltage source converters : A comparative study Conference Proceedings 1995., Tenth Annual Applied Power Electronics Conference and Exposition, 1995. APEC '95. A.M. Hava, T.A. Lipo, W.L. Erdman
1995-002 002 Soft-Switched Inverter for Electric Vehicle Drives APEC Conf. Rec. March 5-9, 1995. pp. 586-591. S. Chen, T.A. Lipo
1995-003 003 Source of Induction Motor Bearing Currents Caused by PWM Inverters IEEE-PES Summer Meeting. S. Chen, T.A. Lipo, D. Fitzgerald
1995-005 005 Modeling and Characterization of Reverse Recovery Performance of High-Power GaAs Schottky and Silicon P-i-N Rectifiers PESC Conf. Rec. June 18-22, 1995. pp. 847-850. C. Winterhalter, S. Pendharkar, K. Shenai
1995-006 006 Design Considerations for Charge Equalization of an Electric Vehicle Battery System. APEC Conf. Rec. March 5-9, 1995. pp. 96-103 IEEE Trans. on Ind. Appl. January/February 1999. Vol. 35. No. 1. pp. 28-35. IEEE Trans on Aerospace & Elec. Sys. January 1998. Vol. 34. No. 1. pp. 238-246. N.H. Kutkut, H.L.N. Wiegman, D.M. Divan, D.W. Novotny
1995-007 007 High-Temperature Characteristics of IGBTs in Soft-and Hard-Switching Converters APEC Conf. Rec. March 5-9, 1995. pp. 733-735. H.H. Li, H. Wiegman, N. Kutkut, A. Kurnia, D. Divan, K. Shenai
1995-008 008 High-Temperature Turn-off Performance of IGBTs in Resonant Converters Power Elec. & Drives Sys. Conf. Rec. 1995. pp. 256-258. H.H. Li, A. Kurnia, D. Divan, K. Shenai
1999-009 009 Inductive Charging Technologies for Electric Vehicles IPEC. April 3-7, 1995. pp. 119-124. N.H. Kutkut, D.M. Divan, D.W. Novotny
1999-010 010 The Effect of Parasitic Bipolar Transistor on the Performance and Reliability of Scaled Vertical Power DMOSFETs PEDS. February 21-24, 1995. pp. 251-255. K. Fischer, K. Shenai
1995-011 011 Magnet Circuit Modeling of the Field Regulated Reluctance Machine. Part I: Model Development IEEE-PES Summer Meeting. 1995. J.D. Law, T.J. Busch, T.A. Lipo
1995-012 012 Magnet Circuit Modeling of the Field Regulated Reluctance Machine. Part II: Saturation Modeling and Results IEEE-PES Summer Meeting. 1995. J.D. Law, T.J. Busch, T.A. Lipo
1995-013 013 Future trends in power electronic control of drives: robust, zero speed sendorless control and new standard approaches for field orientation Department of Electrical and Computer Engineering, University of Wisconsin-Madison, January 1995. R.D. Lorenz
1995-014 014 A novel circuit for accurate characterization and modeling of the reverse recovery of high - power high - speed rectifiers IEEE Transactions on Power Electronics, (Volume:13 , Issue: 5 ). C. Winterhalter, S. Pendharkar, K. Shenai
1995-015 015 Modeling and Characterization of the Reverse Recovery of a High-Power GaAs Schottky Diode IEEE Trans. on Elect. Devices. C. Winterhalter, S. Pendharkar, K. Shenai
1995-016 016 Active Filter Solutions for Utility Interface IEEE International Symposium on Ind. Elec. ISIE '95. July 10-14, 1995. pp. 53-63. S. Bhattacharya, D.M. Divan, B. Banerjee
1995-017 017 Comparison of Power Production Capability Between Doubly Salient Permanent Magnet and Variable Reluctance Type Generators Int'l Agean Conf. on Electrical Machines & Power Electronics Conf. Rec. June 5-7, 1995. B. Sarlioglu, T.A Lipo
1995-018 018 A Novel Doubly Salient Permanent Magnet Generator Capable of Field Weakening Int'l Conf. on Design to Manuf. in Modern Ind. May 29-30, 1995. Y. Li, F. Leonardi, T.A. Lipo
1995-019 019 CFMs - A new family of electrical machines International Conference on Enery Efficiency Improvements in Electric Motors, 29th to 31st October, 1996, Lisbon. T. Lipo, Y. Li
1995-020 020 Measurement and Analysis of Induction Motor Bearing Currents in PWM Inverter Drives IEEE Summer Power Meeting. July 1995. S. Chen, T.A. Lipo, D. Fitzgerald
1995-021 021 Control Topology Options for Single-Phase UPS Inverters In IEEE-PEDES Conf.Rec, New Dehli, India, Jan, 1996, pp. 553-558 and in IEEE Trans. on Ind. Appl., Vol. 33, No. 2, March/April 1997 pp. 493-501. M.J. Ryan, W.E. Brumsickle, R.D. Lorenz
1995-022 022 A High Performance Sine Wave Inverter Controller with Capacitor Current Feedback and "Back EMF" Decoupling Proc. of IEEE, PESC Conf., Atlanta, GA, June 18-22, 1995, pp 507-514. M.J. Ryan, R.D. Lorenz
1995-023 023 Field-Oriented Control of Multi-Phase Induction Machine with Structural Unbalance APEC Conf. Rec. 1996. pp. 380-386. Y. Zhao, T.A. Lipo
1995-024 024 A New Inverter Control Scheme for Induction Motor Drives Requiring Wide Speed Range IEEE Trans. on Ind. Appl. July/August 1996. Vol. 32. No. 4. pp. 938-944. M.O.E. Mohamed, T.A. Lipo
1995-025 025 A Doubly Salient Permanent Magnet Motor Capable of Field Weakening PESC '95 Record., 26th Annual IEEE Power Electronics Specialists Conference, 1995. (Volume:1 ) T. Lipo, Y. Li
1995-026 026 Optimizing Three Phase Current Regulators for Low Inductance Loads IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 2357-2364 S. Bhattacharya, D.G. Holmes, D.M. Divan
1995-027 027 Fish Method Based On-Line Optimal Control for PWM Rectifiers IEEE-PESC Conf. Rec. June 18-22, 1995. pp. 549-555. A. Veltman, J. Duarte
1995-028 028 Flux Based Active Filter Controller In Proc. of IEEE, IAS Conf. Rec., Orlando, FL, Oct. 9-13, 1995, pp. 2483-2491, and in IEEE Trans. on Ind. Appl. May/June 1996 pp. 491-502. S. Bhattacharya, A. Veltman, D.M. Divan, R.D. Lorenz
1995-029 029 Flux Based and Predictive Voltage Based Current Regulators for Motor Drive Applications PEDES. India. 1996. pp. 229-235. A. Veltman, S. Bhattacharya, D.M. Divan
1995-030 030 Start-up and Sensor/Parameter Error Transients in Field Oriented Induction Machines IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 319-326. N.R. Garrigan, D.W. Novotny
1995-031 031 Analysis of Winding Losses in High Frequency Foil Wound Resonant Inductors IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 859-867. N.H. Kutkut, I.T. Wallace, D.M> Divan, D.W. Novotny, E. Yeow
1995-032 032 General Equivalent Circuit of Multi-Winding Coaxial Winding Transformer IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 2507-2514. C. Sun, N.H. Kutkut, D.W. Novotny, D.M. Divan
1995-033 033 Design Parameter Sensitivity and Basic Design Factors for Coaxial Winding Transformers IAS-IPCC Annual Meeting. K.W. Klontz
1995-034 034 Skin and Proximity Effects in Multi-Layer Transformer Windings of Finite Thickness IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 851-858. K.W. Klontz
1995-035 035 Design Considerations and Topology Selection for a 120 KW IGBT Converter for EV Fast Charging IEEE-PESC Conference. June 18-22, 1995. pp. 238-244. IEEE Trans. on Power Elec. January 1998. Vol. 13. No. 1. pp. 169-178. N.H. Kutkut, D.M. Divan, D.W. Novotny, R. Marion
1995-036 036 Inductor Design for High Power Applications with Broad Spectrum Excitations IEEE-PESC Conference Record. June 18-22, 1995. pp. 1057-1063. IEEE Trans. on Power Elec. January 1998. Vol. 13. No. 1. pp. 202-208. I.T. Wallace, N.H> Kutkut, S. Bhattacharaya, D.M. Divan, D.W. Novotny
1995-037 037 Control Methodology for Single Inverter, Series Connected Dual Induction Motor Drives for Electric Vehicles In Proc. of IEEE, IPEC, Yokohama, April 3-7, 1995, pp. 795-800. P.M. Kelecy, R.D. Lorenz
1995-038 038 Flux, Position, and Velocity Estimation in AC Machines at Zero Speed Via Tracking of High Frequency Saliencies In Proc. of 5th European Power Electronics (EPE) Conference, Sevilla, Spain, Sept. 19-21,Vol. 3. 154-160, and in EPE Journal Vol. 9, No. 1-2, August 1999. M.J. Corley, R.D. Lorenz
1995-039 039 Control Methodology for Single Stator, Dual Rotor Induction Motor Drives for Electric Vehicles In Proc. of IEEE, PESC Conf., Atlanta, GA, June 18-22, 1995. pp. 572-578. P.M. Kelecy, R.D. Lorenz
1995-041 041 Active Filter Solutions for Utility Interface of Industrial Loads IEEE-PEDES. January 8-11, 1996. pp. 1078-1084. S. Bhattacharya, D.M. Divan
1995-042 042 Performance Evaluation of an Emitter Switched Thyristor for Resonant Converter Applications IEEE-PEDS. February 21-24, 1995. pp. 13-15. M. Trivedi, C. Winterhalter, H.H. Li, K. Shenai
1995-043 043 Dynamics of IGBTs in Hard- and Soft-Switching Applications IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 1006-1009. IEEE Trans. on Elect.Devices. 1995. pp. 1006-1009. M. Trivedi, H.H. Li, S. Pendharkar, K. Shenai
1995-044 044 Performance evaluation of MCTs and IGBTs in hard - and soft - switching applications 26th Annual IEEE Power Electronics Specialists Conference, 1995. PESC '95 Record., (Volume:1 ) M. Trivedi, H.H. Li, S. Pendharkar, K. Shenai
1995-045 045 A high performance sine wave Inverter Controller with Capacitor Current Feedback and "Back EMF" Decoupling 26th Annual IEEE Power Electronics Specialists Conference, 1995. PESC '95 Record., (Volume:1 ) M.J. Ryan, R.D. Lorenz
1995-046 046 Design and Implementation of a Hybrid Series Active Filter System IEEE-PESC Conf. Rec. June 18-22, 1995. pp. 189-195. S. Bhattacharya, D.M. Divan
1995-047 047 Transducerless Field Orientation Concepts Employing Saturation-Induced Saliencies in Induction Machines In Proc. of IEEE, IAS Conf. Rec., Orlando, FL, Oct. 9-13, 1995, pp. 174-181, and in IEEE-IAS Transactions on Ind. Appl., Vol. 32. No. 6. Nov./Dec. 1996, pp. 1380-1393. P.L. Jansen, R.D. Lorenz
1995-048 048 A Behavioral Circuit Simulation Model for High-Power GaAs Schottky Diodes IEEE Trans.on Elect.Devices. January 1995. Vol. 42. No. 10. pp. 1847-1854. S. Pendharkar, C. Winterhalter, K. Shenai
1995-049 049 Performance Evaluation of High-Power GaAs Schottky and Silicon P-i-N Rectifiers in Hard- and Soft-Switching Applications IEEE Trans. on Power Elec. May 1998. Vol. 13. No. 3. pp. 441-445. S. Pendharkar, C. Winterhalter, M. Trivedi, K. Shenai
1995-050 050 Modeling of Motor Bearing Currents in PWM Inverter Drives. IEEE-IAS Conf. Rec. 1995. pp. 388-393 IEEE Trans. on Ind. Appl. November/December 1996. Vol. 32. No. 6. pp. 1365-1370. S. Chen, T.A. Lipo, D. Fitzgerald
1995-051 051 A circuit simulation model for high - power high - speed GaAs Schottky diodes Eleventh Annual Applied Power Electronics Conference and Exposition, 1996. APEC '96. Conference Proceedings 1996., (Volume:1 ) C. Winterhalter, S. Pendharkar, K. Shenai
1995-052 052 Fault Protection in a Multilevel Inverter Implementation of a Static Condenser IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 2557-2564. G. Sinha, C. Hochgraf, R.H. Lasseter, D.M. Divan, T.A. Lipo
1995-053 053 Analysis of Winding Losses in High Frequency Foil Wound Resonant Inductors IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 859-867. N.H. Kutkut, D.W. Novotny, D.M. Divan, E. Yeow
1995-054 054 Synchronous Frame Based Controller Implementation for a Hybrid Series Active Filter System IEEE-IAS Conf. Rec. October 8-12, 1995. pp. 2531-2540. S. Bhattacharya, D.M. Divan
1995-055 055 Modeling and Control of Multi-Phase Induction Machine with Structural Unbalance IEEE Trans. on Energy Conversion. September 1996. Vol. 11. No. 3. pp. 570-577 & 578-584. Y. Zhao, T.A. Lipo
1995-056 056 Power Swing Damping Control Strategies for FACTS Devices Based Upon Locally Measurable Information IEEE Trans. on Power Systems. August 1995. Vol. 10. No. 3. pp. 1598-1605. J.F. Gronquist, W.A. Sethares, R.H. Lasseter,
1995-057 057 Stabilizing Local Control Strategies for TCSC Devices Using Improved Models Stockholm Power Technology. June 18-22, 1995. Vol. 1. pp. 149-152. J.F. Gronquist, F.L. Alvardo, W.A. Sethares, R.H. Lasseter
1995-058 058 Animated Vectors for Visualization of Power System Phenomena IEEE PICA Conf. Rec. 1995. pp. 121-127. IEEE Trans. on Power Systems. February 1996. Vol. 11. No. 1. pp. 267-273. J.F. Gronquist, W.A. Sethares, F.L. Alvardo, R.H. Lasseter
1995-059 059 Harmonic Instabilities in Static Var Compensators CIGRE Symposium. Tokyo, 1995. R.H. Lasseter, Y. Shern, S.G. Jalali
1995-060 060 Power Oscillation Damping Control Strategies for Facts Devices Using Locally Measurable Quantities IEEE Trans. on Power Systems. Augusty 1995. Vol. 10. No. 3. pp. 1598-1605. J.F. Gronquist, W.A. Sethares, F.L. Alvardo, R.H. Lasseter
1995-061 061 Hierarchical Interface Eases Power System Simulation IEEE Computer Application in Power. Vol. 8., No. 1. 1995. pp. 29-31. R.H. Lasseter
1996-001 001 Cost Benefits and Performance Issues of a Transformer-less STATCON Employing a Multilevel Inverter Submitted to IEEE-PES. Winter meeting. 1996. C. Hochgraf, R.H. Lasseter
1996-002 002 Iron Loss Calculation for Synchronous Reluctance Machines IEEE-PEDES. January 8-11, 1996. pp. 307-312. F. Leonardi, T. Matsuo, T.A. Lipo
1996-003 003 Flux Based and Predictive Voltage Based Current Regulators for Motor Drive Applications Int'l Conf. on Power Elec, Drives, & Energy Sys. for Ind. Growth Conf. Rec. January 8-11, 1996. pp. 229-235. A. Veltman, S. Bhattacharya, D.M. Divan
1996-004 004 Decentralized Operation of Distributed UPS Systems Int'l Conf. on Power Elec, Drives, & Energy Sys. for Ind. Growth Conf. Rec. January 8-11, 1996. pp. 565-571. M.C. Chandorkar, D.M. Divan
1996-005 005 Hybrid Solutions for Improving Passive Filter Performance in High Power Applications APEC Conf. Rec. March 3-7, 1996. pp. 911-917. P.-T. Cheng, S. Bhattacharya, D.M. Divan
1996-006 006 An Approach to Modeling and Field-Oriented Control of a Three-Phase Induction Machine with Structural Unbalance IEEE-APEC Conf. Rec. April 1996. pp. 380-386. Y. Zhao, T.A. Lipo
1996-007 007 Double Bridge Resonant DC Link Converter with Variable Input and Output Frequency IEEE-APEC Conf. Rec. April 1996. pp. 181-186. A. Julian, D. Divan, T. Lipo, F. Nozari, P. Mezs
1996-008 008 A Four Level Rectifier-Inverter Sytem for Drive Applications IEEE-IAS Conf. Rec. October 6-11, 1996. San Diego, CA. pp. 980-987. G. Sinha, T.A. Lipo
1996-010 010 Dynamic Voltage Restoration for Unbalanced Systems. EPRI: The Future of Power Delivery April 9-11, 1996. P.T. Cheng, R.H. Lasseter
1996-011 011 Control Topology Options for Single-Phase UPS Inverters In IEEE-PEDES Conf.Rec, New Dehli, India, Jan, 1996, pp. 553-558 and in IEEE Trans. on Ind. Appl., Vol. 33, No. 2, March/April 1997 pp. 493-501. M.J. Ryan, W.E. Brumsickle, R.D. Lorenz
1996-012 012 Neutral-to-Ground Voltage Minimization in a PWM-Rectifier/Inverter Configuration IEE Conf. on Power Elec. and Variable Speed Drives. September 23-25, 1996. pp. 564-568. A.M. De Broe, A.L. Julian, T.A. Lipo
1996-013 013 A Matrix Converter Using Reverse Blocking NPT-IGBT's and Optimized Pulse Patterns IEEE-PESC Conf. Rec. June 1996. pp. 107-113. S. Bernet, T. Matsuo, T.A. Lipo
1996-015 015 Design Considerations and Test Results for a Doubly Salient PM Motor with Flux Control IEEE-IAS Conf. Rec. October 6-11, 1996. pp. 458-463. F. Leonardi, Y. Li, T. Matsuo, T.A. Lipo, P. McCleer
1996-016 016 A General Approach to Sizing and Power DensityEquations for Comparison of Electrical Machines IEEE-IAS Conf. Rec. October 1996. pp. 836-842. IEEE Trans. on Ind. Appl. January/February 1998. Vol. 34. No. 1. pp. 92-97. S. Huang, J. Luo, F. Leonardi, T.A. Lipo
1996-017 017 Elimination of Common Mode Voltage in Three-Phase Sinusoidal Power Converters. IEEE-PESC. June 24-27, 1996. pp. 1968-1972 IEEE Trans. on Power Elec. Vol. 14. No. 6. pp. 982-989. T. Lipo, G. Oriti, A. Julian
1996-018 018 Active Filter Solutions for Utility Interface of Industrial Loads IEEE-PEDES Conf. Rec. January 1996. pp. 1078-1084. S. Bhattacharya, D.M. Divan
1996-019 019 Line Harmonics Reduction in High Power System Using Square-Wave Inverters. IEEE-PESC. Italy. June 1996. pp. 1135-1141 IEEE Trans. on Power Elec. March 1999. Vol. 14. No. 2. pp. 265-272. P.-T. Cheng, S. Bhattacharya, D.M. Divan
1996-020 020 Experimental Comparison of Motor Bearing Currents with PWM Hard and Soft Switched Voltage Source Inverters IEEE-PESC. Italy. June 1996. pp. 1528-1534. IEEE Trans. on Power Elec. Vol. 14. No. 6. pp. 552-562. S Bhattacharya, L. Resta, D.M. Divan, D.W. Novotny, T.A. Lipo
1996-021 021 Control of Square-Wave Inverters in High Power Hybrid Active Filter Systems. IEEE-IAS Conf. Rec. San Diego, CA. October 1996. pp. 1106-1113 IEEE Trans. on Ind. Appl. May/June 1998. Vol. 34. No. 3. pp. 458-472. S. Bhattacharya, Cheng P.-T., D.M. Divan
1996-022 022 Parallel Active Filter System Implementation and Design Issues for Utility Interface of Adjustable Speed Drive Systems IEEE-IAS Conf. Rec. San Diego, CA. October 1996. pp. 1032-1039. S. Bhattacharya, T.M. Frank, D.M. Divan, B. Banerjee
1996-023 023 Engine Control Strategy for a Series Hybrid Electric Vehicle Incorporating Load-Leveling and Computer Controlled Energy Managment SAE Congress paper # 960230. Detroit, MI. February 1996. C.G. Hochgraf, M.J. Ryan, H.L.N. Wiegman
1996-024 024 A Novel Two Phase Doubly Salient Permanent Magnet Motor IEEE-IAS Conf. Rec. October 1996. pp. 808-815. X. Luo, D. Qin, T.A. Lipo
1996-026 026 Modeling and Analysis of a Wide Speed Range Induction Motor Drive Based on Electronic Pole Changing. IEEE-IAS Conf. Rec. October 1996. pp. 357-364 IEEE Trans. on Ind. Appl. September/October 1997. Vol. 33. No. 5. pp. 1177-1184. MOE Mohamed, T.A. Lipo
1996-027 027 Application of the Matrix Converter to Induction Motor Drives IEEE-IAS Conf. Rec. October 1996. pp. 60-67. T. Matsuo, S. Bernet, R.S. Colby, T.A. Lipo
1996-028 028 Modeling and Simulation of Matrix Converter/Induction Motor Drive IMACS Conference. September 1996. Mathematics & Computers in Simulation. May 1998. Vol. 46. No. 3-4. pp. 175-195. T. Matsuo, S. Bernet, R.S. Colby, T.A. Lipo
1996-029 029 Analytical Estimation and Reduction of Conducted EMI Emissions in High Power PWM Inverter Drives IEEE PESC Conf. Rec. Italy. June 1996. pp. 1169-1175. E. Zhong, T.A. Lipo, J.R. Jaeschke, D. Gritter
1996-030 030 Rotor Position and Velocity Estimation for a Permant Magnet Synchronuos Machine at Standstill and High Speeds In IEEE, IAS Conf. Rec., Oct 5-10, 1996, pp. 36-41, and in IEEE Trans. on Ind. Appl., Vol. 34, No. 4, July/August 1998 pp. 784-789. M.J. Corley, R.D. Lorenz
1996-031 031 Circulating Type Motor Bearing Current in Inverter Drives IEEE-IAS Conf. Rec. October 1996. pp. 162-167. IEEE Trans. on Ind. Appl. January/February 1998. Vol. 4. No. 1. pp. 32-38. S. Chen, T.A. Lipo, D.W. Novotny
1996-032 032 New Drive Control Algorithms (State Control, Observers, Self-Sensing, Fuzzy Logic, and Neural Nets) In Proc. of PCIM Conf., Sept. 3-6, 1996, Las Vegas, NV, pp. 275-289. R.D. Lorenz
1996-033 033 Utilization of Third Harmonic-Induced-Voltages in PM Generators IEEE-IAS Conf. Rec. San Diego, CA. October 1996. pp. 525-532. A. Munoz-Garcia, D.W. Novotny
1996-034 034 Reluctance Motor Control for Fault-Tolerant Capability IEEE-IEMDC. Milwaukee, WI. May 18-21, 1997. pp. WA1-1.1 - WA1-1.6. D. Qin, X. Luo, T.A. Lipo
1996-035 035 A General Approach to Sizing and Power Density Equations for Comparison of Electrical Machines IEEE-IAS Conf. Rec. San Diego, CA. October 1996. pp. 836-842. S. Huang, J. Luo, F. Leonardi, T.A. Lipo
1996-036 036 Elimination of Common Mode Voltage in Three-Phase Sinusoidal Power Converters IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 14, NO. 5, SEPTEMBER 1999. A. Julian, T.A. Lipo, G. Oriti
1996-037 037 Current-Clamped, Modified Series Resonant DC-Link Power Converter and Control Strategies IEE Trans. Japan. 1996. Vol. 116-D. No. 11. pp. 1145-1152. IEEE Trans. on Power Elec. March 1997. Vol. 12. No. 2. pp. 201-212. S.G. Abeyratne, J. Horikawa, Y. Murai, T.A. Lipo
1996-038 038 The Auxiliary Resonant Commutated Pole Matrix Converter-A New Topology for High Power Applications IEEE-IAS Conf. Rec. October 1996. pp. 1242-1249. S. Bernet, K. Bernet, T.A. Lipo
1996-040 040 A Four Level Rectifier-Inverter System for Drive Applications IEEE-IAS Conf. Rec. October 1996. pp. 980-987. IEEE Trans. on Ind. Appl. January/February 1998. Vol. 4. No. 1. pp. 66-74. G. Sinha, T.A. Lipo
1996-041 041 Design Considerations and Test Results for a Doubly Salient PM Motor with Flux Control IEEE-IAS Conf. Rec. San Diego, CA. October 1996. pp. 458-463. F. Leonardi, T. Matsuo, Y. Li, T.A. Lipo, P. McCleer
1996-042 042 Advanced Motor Technologies: Converter Fed Machines (CFMs) Int'l Conf. on Energy Efficiency Improvements in Electric Motors. October 1996. T.A. Lipo
1996-043 043 Space Vector Analysis and Modulation Issues of Passively Clamped Quasi-Resonant Inverters IEEE-IAS Conf. Rec. 1996. pp. 1179-1185. IEEE Trans. on Ind. Appl. July/August 1998. Vol. 34. No. 4. pp. 861-869. B.J. Cardoso-Filho, T.A. Lipo
1996-045 045 High Range-to-Resolution Ratio, Optical Sensing Technique for High Speed Surface Geometry Measurements SPIE's Milestone Series of Selected Reprints on Optical Techniques for Industrial Inspection. 1996. Vol. MS 135. p. 135-141. R.D. Lorenz, A. Novel
1996-048 048 Input Power Factor Control of AC-DC Series Resonant DC Link Converter Using PID Operation IEEE Trans. on Power Elec. January 1996. Vol. 11. No. 1. pp. 43-48. H. Soebagia, M. Yochida, Y. Murai, T.A. Lipo
1996-049 049 Current peak limiting for a series resonant DC link power conversion using a saturable core Electric Machines and Power Systems. 1996. Vol. 24. No. 1. pp. 51-64. Y. Murai, S.G. Abeyratne, T.A. Lipo, P. Caldeira
1996-051 051 A New Permanent Magnet Motor Structure with True Field Weakening Electric Machines and Power Systems. 1996. Vol. 24. No. 5. pp. 497-510. A. Shakal, Y. Liao, T.A. Lipo
1996-052 052 Modeling and Control of Multi-Phase Induction Machine with Structural Unbalance, Part 1: Machine Modeling and Multi-Dimensional Current Regulator IEEE Trans. on Energy Conversion. September 1996. Vol. 11. No. 3. pp. 570-577. Y. Zhao, T.A. Lipo
1996-053 053 Modeling and Control of Multi-Phase Induction Machine with Structural Unbalance, Part 2: Field Oriented Control and Experimental Verification IEEE Trans. on Energy Conversion. September 1996. Vol. 11. No. 3. pp. 578-584. Y. Zhao, T.A. Lipo
1996-054 054 A strategy to isolate the switching device fault of a current regulated motor drive Electrical Machines and Power Systems. December 1996. Vol. 24. No. 8. pp. 911-920. J.R. Fu, T.A. Lipo
1996-055 055 Study of a Permanent Magnet Excited Axial Flux Electromagnetic Differential Motor for Wheel Direct Drive Application SPEEDAM. 1996. Vol. C4. pp. 21-28. F. Caricchi, F. Crescimbini, T.A. Lipo
1996-056 056 A Novel Soft-Switched Inverter for AC Motor Drives IEEE Trans. on Power Elec. July 1996. Vol. 11. No. 4. pp. 653-659. S, Chen, T.A. Lipo
1996-057 057 A New Control Strategy for Optimum Efficiency Operation of a Synchronous Reluctance Motor IEEE-IAS Conf.Rec. October 1996. pp. 109-116. IEEE Trans. on Ind. Appl. September/October 1997. Vol. 33. No. 5. pp. 1146-1153. T. Matsuo, A. El-Antably, T.A. Lipo
1997-001 001 A Synchronous-Frame Controller for a Single-Phase Sine Wave Inverter In Proc. of IEEE, APEC Conf., Atlanta, GA, Feb. 23-27, 1997, pp 813-819. M.J. Ryan, R.D. Lorenz
1997-002 002 A New Induction Motor Open-Loop Speed Control Capable of Low Frequency Operation IEEE-IAS Conf. Rec. October 5-9, 1997. Vol. 1. pp.579-586. A. Munoz-Garcia, T.A. Lipo, D.W. Novotny
1997-003 003 Hybrid Solutions for Improving Passive Filter Performance in High Power Applications IEEE Trans. on Ind. Appl. May/June 1997. Vol. 33. No. 3. pp. 732-747. S. Bhattacharya, P.-T. Cheng, D.M. Divan
1997-004 004 A High Performance Generalized Discontinuous PWM Algorithm. IEEE-APEC Conf. Rec. February 23-27, 1997. pp. 886-894 IEEE Trans. on Ind. Appl. September/October 1998. Vol. 34. No. 5. pp. 1059-1071. A.M. Hava, R.J. Kerkman, T.A. Lipo
1997-007 007 Wide Bandwidth Flux, Position, and Velocity Estimation in AC machines at Any Speed (Including Zero) Using Multiple Saliencies. In Proc. of 6th European Power Electronics (EPE) Conf. Rec., Sept. 8-10, 1997, Trondheim, Norway, pp. 1.530-1.535 M.W. Degner, R.D. Lorenz
1997-008 008 Position Estimation in Induction Machines Utilizing Rotor Bar Slot Harmonics and Carrier Frequency Signal Injection In Proc. of IEEE-IAS, PCC Nagaoka Technical Conference, Nagaoka, Japan, August, 1997, pp. 69-72, and will be in IEEE Trans. on Ind. Appl., May/June 2000. M.W. Degner, R.D. Lorenz
1997-009 009 Analysis and Design of Current Regulators Using Complex Vectors In Proc. of IEEE, IAS Annual Technical Conference, Oct. 4-10, 1997, New Orleans, pp. 1504-1511, and will be in IEEE Trans. on Ind. Appl., May/June 2000. F. Briz, R.D. Lorenz,
1997-010 010 Using Multiple Saliencies for the Estimation of Flux, Position, and Velocity in AC Machines, Sept/Oct 1998 pp. 101997-1104. In Proc. of IEEE, IAS Annual Technical Conference, Oct. 4-10, 1997, New Orleans, pp. 760-767, and in IEEE Trans. on Ind. Appl., Vol. 34, No. 5 M.W. Degner, R.D. Lorenz
1997-011 011 A Novel Method for Measuring Induction Machine Magnetizing Inductance IEEE-IAS Conf. Rec. October 5-9, 1997. Vol.1. pp.234-238. A. Stankovic, E.R. Benedict, V. John, T.A. Lipo
1997-012 012 Design and Construction of a Permanent Magnet Axial Flux Synchronous Generator IEEE-IEMDC. May 18-21, 1997. MA1-4.1 - MA1-4.3. R.R. Wallace, T.A. Lipo, L.A. Moran, J.A. Tapia
1997-013 013 A New ZVS LCL-Resonant Push-Pull DC-DC Converter Topology In Proc. of IEEE, IAS Annual Technical Conference, Oct. 4-10, 1997, New Orleans, pp. 1673-1680, and in IEEE Trans. on Ind. Appl., Vol. 34, No. 5, Sept/Oct 1998 pp. 1164-1174. M.J. Ryan, W.E. Brumsickle, D.M. Divan, R.D. Lorenz
1997-014 014 A Synchronous/Permanent Magnet Hybrid AC Machine IEEE-PES Summer Meeting. 1997. IEMDC Conf. Rec. 1999. pp. 19-21 X. Luo, T.A. Lipo
1997-015 015 C.B. Jacobina. Pulsed Dc-Link Current Converters - A Review IEEE-IAS Conf. Rec. October 5-9,1997. Vol.2. pp. 1406-1413. E.R. da Silva, Y. Murai, T.A. Lipo, L.P.B. de Oliveria
1997-017 017 Self Excited Variable Reluctance Generator IEEE-IAS Conf. Rec. October 5-9,1997. Vol.1. pp.653-660 T. Matsuo, J. Luo, E. Hoffman, T.A. Lipo
1997-018 018 Bearing Currents and Shaft Voltages of an Induction Motor Under Hard and Soft Switching Inverter Excitation. IEEE-IAS Conf. Rec. October 5-9,1997. Vol.1. pp.167-173 IEEE Trans. on Ind. Appl. September/October 1998. Vol. 34. No. 5. pp. 1042-1048. S. Chen, T.A. Lipo
1997-019 019 A Four Level Inverter Based Drive With A Passive Front End IEEE-PESC Summer Meeting. 1997. pp. 590-596. G. Sinha, T.A. Lipo
1997-020 020 A New Space Vector Modulation Strategy for Common Mode Voltage Reduction IEEE-PESC. June 22-27, 1997. pp. 1541-1546. G. Oriti, A.L. Julian, T.A. Lipo
1997-021 021 A New Control Strategy for the PWM Current Stiff Rectifier/Inverter with Resonant Snubbers Submitted to IEEE-PESC. 1997. pp. 573-579. B.J. Cardoso-Filho, S. Bernet, T.A. Lipo
1997-022 022 Current Stiff Converter Topologies with Resonant Snubbers IEEE IAS Conf. Rec. October 5-9, 1997. Vol.2. pp. 1322-1329. B.J.C. Filho, S. Bernet, T.A. Lipo
1997-023 023 Dynamic Overmodulation Characteristics of Triangle Intersection PWM Methods. IEEE-IAS Conf. Rec. October 1997. Vol.2. pp.1523-1528 IEEE Trans. on Ind. Appl. July/August 1999. Vol. 35. No. 4. pp. 896-907. A.M. Hava, S.K. Sul, R.J. Kerkman, T.A. Lipo
1997-024 024 An Inverter/Motor Drive with Common Mode Voltage Elimination. IEEE IAS Conf. Rec. October 5-9,1997. Vol.1. pp.587-592 G. Oriti, A.L. Julian, T.A. Lipo
1997-025 025 Simple Analytical and Graphical Tools for Carrier Based PWM Methods IEEE-PESC Conf. Rec. 1997. Vol. 2. pp. 1462-1471. IEEE Trans. on Power Elec. January 1999. Vol. 14. No. 6. pp. 49-61 A.M. Hava, R.J. Kerman, T.A. Lipo
1997-026 026 Innovative Electrical Machines for Traction Applications. World Cong. on Railway Research Florence, Italy. November 1997. pp. 459-466. S. Tidu, B. Pietra, J. Luo, T.A. Lipo
1997-027 027 The DSPM: An AC Permanent Magnet Traction Motor with True Field Weakening International Conf. on "All Electric Combat Vehicle". Detroit, MI. 1997. F. Leonardi, P.J. McCleer, T.A. Lipo
1997-028 028 Modern Control of Drives In Proc. of Brazilian Power Electronics Conf., COBEP'97, Belo Horizonte, MG, Brazil, Dec 2-5, 1997, pp. 45-54. R.D. Lorenz
1997-029 029 New Observer Based DFO Scheme for Speed Sensorless Field-Oriented Drives for Low to Zero Speed Operation IEEE Trans. on Power Elec. September 1998. Vol. 13. No. 5. pp. 959-968. E.K.K. Sng, A.C. Liew, T.A. Lipo
1997-030 030 Analysis and Evaluation of the Transverse Flux Circumferential Current Machine IEEE-IAS Conf. Rec. October 5-9,1997. Vol. 1. pp. 378-384. S. Huang, J. Luo, T.A. Lipo
1997-031 031 A New Modulation Strategy for Improved DC Bus Utilization in Soft and Hard Switched Multilevel Inverters IECON. November 1997. pp. 670-675. G. Sinha, T.A. Lipo
1998-001 001 DC Link Voltage Control of Reduced Switch VSI-PWM Rectifier/Inverter System IECON. Vol. 2. pp. 833-838. November 1997. G.-T. Kim, T.A. Lipo
1998-002 002 On-Line Dead Time Compensation Technique for Open-Loop PWM-VSI Drives IEEE-APEC Conf. Rec. February 1998. Vol. 1. pp. 95-100. IEEE Trans. on Power. Elec. July 1999. Vol. 14. No. 4. pp. 683-689. A. Munoz-Garcia, T.A. Lipo
1998-003 003 Active Filtering for Common Mode Conducted EMI Reduction in Voltage Source Inverters IEEE-APEC Conf. Rec. February 1998. Vol. 2. pp. 934-939. A.L. Julian, R. Cuzner, G. Oriti, T.A. Lipo
1998-004 004 A Hybrid Multilevel Inverter Topology for Drive Applications IEEE-APEC Conf. Rec. February 1998. Vol. 2. pp. 523-529. M.D. Manjrekar, T.A. Lipo
1998-005 005 AC to AC Power Conversion Based on Matrix Converter Topology with Unidirectional Switches. IEEE-APEC Conf. Rec. February 1998. Vol. 1. pp. 301-307. IEEE Trans. on Ind. Appl. January/February 2000. Vol. 36. No. 1. pp. 139-145. S. Kim, S.-K. Sul, T.A. Lipo
1998-006 006 Reduced Switching Stress in High-Voltage IGBT Inverters via a Three-Level Structure IEEE-APEC Conf. Rec. February 1998. Vol. 2. pp. 544-550. W.E. Brumsickle, D.M. Divan, T.A. Lipo
1998-007 007 Fast Clamped Short Circuit Protection of IGBTs. IEEE-APEC Conf. Rec. February 1998. Vol. 2. pp. 724-730 IEEE-IAS Trans. on Ind. Appl. March/April 1999. Vol. 35. No. 2. pp. 477-486. V. John , B.-S. Suh, T.A. Lipo
1998-008 008 A Reduced Parts Count Realization of the Resonant Snubbers for High Power Current Stiff Converters IEEE-APEC Conf. Rec. February 1998. Vol. 2. pp. 558-564. B.J. Cardoso Filho, T.A. Lipo
1998-009 009 High Voltage Buck Converter Topology for Common Mode Voltage Reduction IEEE-APEC Conf. Rec. February 1998. Vol. 2. pp. 940-943. A. Rockhill, T.A. Lipo, A.L. Julian
1998-010 010 Battery State Control Techniques for Charge Sustaining Applications. Netherland American Foundation SAE 1998 Congress. Session PC 25B. Paper #981129. H.L.N. Wiegman, A.J.A. Vandenput
1998-011 011 Investigation of a Modified Single Phase Inverter Topology for Reduction of Common Mode Voltage IEEE-PESC. June 1999. Vol. 2. pp. 850-854. A. Rao, A.L. Julian, T.A. Lipo
1998-012 012 A New Induction Motor V/F Control Method Capable of High Performance Regulation at Low Speeds IEEE Trans. on Ind. Appl. July/August 1998. Vol. 34. No. 4. pp. 813-821. A. Munoz-Garcia, T.A. Lipo, D.W. Novotny
1998-013 013 Dual Stator Winding Induction Machine Drive IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. Vol. 1. pp. 601-608. A. Munoz-Garcia, T.A. Lipo
1998-014 014 Complex Vector Model of the Squirrel Cage Induction Machine Including Instantaneous Rotor Bar Currents IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. Vol. 1. pp. 57-64. IEEE Trans. on Ind. Appl. November/December 1999. Vol. 35. No. 6. pp. 1332-1340. A. Munoz-Garcia, T.A. Lipo
1998-015 015 Nonlinear Modeling and Simulation of Single Phase Doubly Salient Permanent Magnet Generator IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. Vol. 1. pp. 18-26. B. Sarlioglu, T.A Lipo
1998-016 016 A Course Portfolio: Teaching Modern Electrical and Electro-Mechanical Power Conversion to Undergraduate Engineering Students ICEM Conf. Istanbul, Turkey. Sept. 2-4, 1998. Vol. 1. pp. 657-662. B. Sarlioglu, H. Wiegman, R.D. Lorenz
1998-017 017 Control of Square-Wave Inverters in High Power Hybrid Active Filter Systems IEEE-IAS Conf. Rec. 1996. pp. 1106-1113. IEEE Trans. on Ind. Appl. May/June 1998. Vol. 34. No. 3. pp. 458-472. P.-T. Cheng, S. Bhattacharya, D. Divan
1998-018 018 Line Harmonics Reduction in High Power Systems Using Square-Wave Inverter Based Dominant Harmonic Active Filter IEEE Trans. on Power Elec. March 1999. Vol. 14. No. 2. pp. 265-272. P.-T. Cheng, S. Bhattacharya, D. Divan
1998-019 019 Application of Dominant Harmonic Active Filter System with 12 Pulse Nonlinear Loads IEEE Trans. on Power Delivery. April 1999. Vol. 14. No. 2. pp. 642-647. P.-T. Cheng, S. Bhattacharya, D. Divan
1998-020 020 Experimental Verification of Dominant Harmonic Active Filter for High Power Applications IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. Vol. 2. pp. 1400-1407. P.-T. Cheng, S. Bhattacharya, D. Divan
1998-021 021 The Effects of Saturation Induced Saliency Movement on Flux Angle Estimation In Proc. of IEEE, 5th International Workshop on Advanced Motion Control, Coimbra Portugal, June 29-July 1, 1998, pp. 369-374. M.L. Aime, M.W. Degner, R.D. Lorenz
1998-022 022 Modeling of UPS Inverters: A Geometric Approach In Proc. of IEEE-IES Annual Conf., IECON98 , Aachen, Germany, August 31-Sept. 4, 1998 and in IEEE Trans. on Ind. Electronics., Vol. 46, No. 6, Dec. 1999, pp. 1183-1192. M.J. Ryan, R.D. Lorenz
1998-023 023 Sensorless Control of a SRM at Low Speeds and Standstill Based on Signal Power Evaluation In Proc. of IEEE-IES Annual Conf., IECON98 , Aachen, Germany, August 31-Sept. 4, 1998. A. Brosse, G. Henneberger, M. Schneidermeyer, R.D. Lorenz, N. Nagel
1998-024 024 Saturation Measurements in AC Machines Using Carrier Signal Injection66. In Proc. of IEEE, IAS Annual Tech. Conf., St. Louis, MO. Oct. 12-16, 1998, pp. 159-1 M.L. Aime, M.W. Degner, R.D. Lorenz
1998-026 026 Comparison of Carrier Signal Voltage and Current Injection for the Estimation of Flux Angle or Rotor Position In Proc. of IEEE, IAS Annual Tech. Conf., St. Louis, MO, Oct. 12-16, 1998, pp. 452-459. L.A.S. Ribeiro, M.W. Degner, F. Briz, R.D. Lorenz
1998-027 027 Rotating Vector Methods for Sensorless, Smooth Torque Control of a Switched Reluctance Motor Drive In Proc. of IEEE, IAS Annual Tech. Conf., St. Louis, MO, Oct. 12-16, 1998, pp. 723-730 and to appear in IEEE Trans. on Ind. Appl in March/April 2000. N.J. Nagel, R.D. Lorenz
1998-029 029 Dynamic Analysis of Current Regulators for AC Motors Using Complex Vectors In Proc. of IEEE, IAS Annual Tech. Conf., St. Louis, MO, Oct. 12-16, 1998, pp. 1253-1260, and in IEEE Trans. on Ind. Appl, Nov/Dec 1999, pp. 1424-1432. F. Briz, M.W. Degner, R.D. Lorenz
1998-030 030 Current and Flux Regulation in Field-Weakening Operation In Proc. of IEEE, IAS Annual Tech. Conf., St. Louis, MO, Oct. 12-16, 1998, pp. 524-531 F. Briz, A.B. Diez, M.W. Degner, R.D. Lorenz
1998-031 031 Transient Modeling and Analysis of Motor Terminal Voltage on PWM Inverter-Fed AC Motor Drives IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. Vol. 1. pp. 773-780. E. Zhong, T.A. Lipo, S. Rossiter
1998-032 032 Space Vector Analysis and Modulation Issues of Passively Clamped Quasi-Resonant Inverters IEEE-IAS Conf. Rec. 1996. Vol. 2. pp. 1179-1185. IEEE Trans. on Ind. Appl. July/August 1998. Vol. 34. No. 4. pp. 861-869. B.J. Cardoso Filho, T.A. Lipo
1998-033 033 Introduction to a Axial Flux Circumferential Current Permanent Magnet (AFCC) Machine IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. Vol. 1. pp. 144-151. J. Luo, D. Qin, T.A. Lipo, S. Huang, S. Li
1998-034 034 High Efficiency Battery State Control and Power Capability Prediction In Proc. of 15th EV Symposium, Brussels, Belguim, Oct. 1-3, 1998. H.L.N. Wiegman, R.D. Lorenz
1998-035 035 Switching Angles and DC Link Voltages Optimization for Multilevel Cascade Inverters 1998 International Conference on Power Electronic Drives and Energy Systems for Industrial Growth, 1998. Proceedings. (Volume:1 ) Q. Jiang, T.A. Lipo
1998-036 036 High Performance Active Gate Drive for High Power IGBTs IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. Vol. 2. pp. 1519-1529. IEEE Trans. on Ind. Appl. September/October 1999. Vol. 35. No. 6. pp. 1108-1117. V. John, B.-S. Suh, T.A. Lipo
1998-037 037 The Integration of Machine Fault Detection into an Indirect Field Oriented Induction Machine Drive Control Scheme - The Vienna Monitoring Method IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. Vol. 1. pp. 278-285. R.S. Wieser, M. Schagginger, Ch. Kral
1998-038 038 Robust Induction Machine Cage Monitoring Technique for Highly Distorted Voltage and Current Waveforms - The Vienna Method IEE-PEVD. September 1998. pp. 194-199. R. Wieser, Ch. Kral, F. Pirker, M. Schagginger
1998-039 039 A Dynamic Performance Booster for Current Regulated Induction Machines at High Speed Utilizing Trapped Rotor Flux ICEM. September 1998. Vol.1. pp. 221-226 . R. Wieser
1998-040 040 High Sensitive Rotor Cage Monitoring During Dynamic Load Operation - The Vienna Method ICEM. September 1998. Vol. 1. pp. 432-437. R. Wieser, Ch. Kral, F. Pirker, M. Schagginger
1998-041 041 The Vienna Induction Machine Method - On the Impact of the Field Oriented Control Structure on Real Operational Behavior of a Faulty Machine IECON. September 1998. Vol. 3. pp. 1544-1549. R.S. Wieser, C. Kral, F. Pirker, M. Schagginger
1998-042 042 Sequences of Field Oriented Control for the Detection of Faulty Rotor Bars in Induction Machines -The Vienna Monitoring Method AMC. June/July 1998. pp. 463-468. R. Wieser, Ch. Kral, F. Pirker, M. Schagginger
1998-043 043 A Dynamic Performance Booster for Synchronous Frame Current Regulators of AC Machines at High Back-EMF Operation Speedam. June 1998. Session 4. pp. 39-44. R. Wieser
1998-044 044 Sensitive Rotor Cage Monitoring without Frequency Analysis - The Vienna Method Speedam. June 1998. Session 3. pp. 21-26. R. Wieser, Ch. Kral, F. Pirker, M. Schagginger
1998-045 045 The Vienna Induction Monitoring Method - A Structural Analysis of a Faulty Machine Behavior at a Stiff Voltage Supply PCIM. May 1998. pp. 425-432. R. Wieser, Ch. Kral, F. Pirker, M. Schagginger
1998-046 046 Fundamental Analysis of a Battery State Regulation Technique Based on Terminal Voltage In Proc. of IEEE 17th Digital Avionics System Conf., Seattle WA, Oct. 31-Nov. 6, 1998. H.L.N. Wiegman, R.D. Lorenz
1998-047 047 Induction Motor Bearing Currents and Shaft Voltages Caused by PWM Inverters CAST Conf. of Young Scientists. Beijing, China. August 1998. S. Chen, T.A. Lipo
1998-048 048 A Generalized Structure of Multilevel Power Converter. PEDES. Perth, Australia. November/December 1998. Vol. 1. pp. 62-67 M.D. Manjrekar, T.D. Lipo
1998-049 049 Multilevel Power Conversion - An Overview of Topologies and Modulation Strategies Optimization of Electrical & Electronic Equip. 1998. Vol. 2. pp. AD11-AD24. B.-S. Sub, G. Sinha, M.D. Manjrekar, T.D. Lipo
1998-050 050 Flux Tracking Methods for Direct Field Orientation ICEM Conf. Rec. 1998. Vol. 2. pp. 1022-1029. Electric Machines and Power Systems. 1999. Vol. 27. pp. 905-920. M.D. Manjrekar, T.D. Lipo, S.-G. Chang, K.-S. Kim
1998-051 051 Mathematics and Computers in Simulation Mathematics and Computers in Simulation 46. 1998. pp. 175-195. T. Matsuo, S. Bernet, R.S. Colby, T.A. Lipo
1998-052 052 A New Dual Three-Phase Drive System with a Reduced Switch Count IEEE-IAS Conf. Rec. St. Louis, MO. October 1998. pp. 781-788. E. Ledezma, A. Munoz-Garcia, T.A. Lipo
1998-053 053 Measuring the Location of Saliencies in AC Machines IEEE-IES-IECON. September 1998. pp. 286-291. M.L. Aime, M.W. Degner, N.H. Tice, R.D. Lorenz
1998-054 054 Future Trends in Control Applications of Artificial Neural Networks and Adaptive Control In Proc. of IEEE, Future of Electronic Power Processing Conf., (FEPPCON), Kruger National Park, South Africa, July 11-14, 1998, pp. A40-49. R.D. Lorenz
1999-001 001 m-Controller Based PLL Control for SR Drive. IEEE-IEMDC Conf. Rec. Seattle,WA. May 1999. pp. 25-27. The switched reluctance drive is known to provide good adjustable speed characteristics. However, higher torque ripple and lack of the precise speed control are drawbacks. To reduce torque ripple and to have precise speed control, a PLL technique is adopted The PLL control technique in conjunction with dynamic dwell angle control scheme has good speed regulation characteristics A digital control system with an 80c195kc micro-controller is used to realize this drive system. Test results show that the system has the ability to achieve dynamic and precise speed control. J.-W. Ahn
1999-002 002 Digital PLL Technique for Precise Speed Control of SR Drive. IEEE-PESC Conf. Rec. Charleston, SC. June/July 1999. Vol. 2. pp. 815-819. J.-W. Ahn
1999-003 003 Generic Torque-Maximizing Design Methodology of Permanent Magnet Vernier Machine IEEE-IEMDC Conf. Rec. Seattle,WA. May 1999. pp. 522-524. A Permanent Magnet Vernier Machine has a toothed-pole structure, and its nonlinear relationship between the dimensions and the magnetic field makes its design cumbersome. This paper presents a novel generic design methodology of the machine which brings out tie torque-maximizing structure in a convenient manner. Various suggestions concerning the design are also set forth. A. Toba, T.A. Lipo
1999-004 004 Assessment of Power Generation Capability of Doubly-Salient PM Generator IEEE-IEMDC Conf. Rec. Seattle, WA. May 1999. pp. 549-552. In this paper, the characterization of the power production capability of the DSPM generator under loaded conditions will be fully explored by using relevant power electronic circuit implementations. The ac output of the DSPM generator can easily be rectified to power a dc load. In certain applications, the requirement is for constant dc rectifier current, while in some applications dc voltage should be constant. The required rectification can be done by using a variety of power electronics circuits. A diode bridge rectifier with constant current and constant voltage output, and a PWM boost controller with a hysteresis current controller are the implementations of interest. In the case of an actively switched converter, semiconductor devices are used to shape the current, and hence provide a controlled power transfer. B. Sarlioglu, T.A. Lipo
1999-005 005 A Synchronous/Permanent Magnet Hybrid AC Machine IEEE-IEMDC Conf. Rec. Seattle, WA. May 1999. pp. 19-21. In this paper, a synchronous/permanent magnet hybrid (SynPM) machine is presented. It is shown that the machine has good power density and efficiency, and that the machine has true field regulation capability. The principle of operation, finite element analysis and simulation of this new machine are investigated in the paper. X. Luo, T.A. Lipo
1999-006 006 Electric Drives Technology - Part Way to Where? IEEE-IEMDC Conf. Rec. Seattle, WA. May 1999. pp. 1-3. Power electronic converters have clearly had a dramatic impact on motor drive technology.However,successful applications of thk technology have not been all pervasive but relatively selective. ‘1’Mspaper attempts to summarize the present status of thk technology at to illustrate that, perhaps, the greatest challenges and rewards lie ahead of us. T.A. Lipo
1999-007 007 Performance Improvement of Half Controlled Three Phase PWM Boost Rectifier IEEE-PESC Conf. Rec. Charleston, SC. June/July 1999. Vol. 1. pp. 319-324. The potential of the half controlled three phase pulse-width modulated (PWM) boost rectifier is investigated based on theoretical analysis, simulations and experiments. The main advantages of this rectifier are 1) a simpler and economical system com- pared to a full controlled PWM rectifier (reduced controlled switch count, single power supply for gate drives, and shoot-through free leg structure) and 2) better performance compared to a diode rectifier (actively controllable dc link voltage and lower input cur- rent total harmonic distortion (THD)). In particular, it is shown in this paper that input current THD of this rectifier can be reduced by intentionally introducing a lagging power factor current command. Several issues for further performance improvement are pointed out for future work. J. Kikuchi, M.D. Manjrekar, T.A. Lipo
1999-008 008 Control Strategies for a Hybrid Seven-Level Inverter EPE Conf. Rec. Lausanne, Switzerland. September 1999. R. Lund, M.D. Manjrekar, P. Steimer, T.A. Lipo
1999-009 009 Co-Axial Current Transformer for Test and Characterization of High Power Semiconductor Devices Under Hard and Soft-Switching IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 3. pp. 2009-2016. IEEE Trans. on Ind. Appl. July/August 2000. Current measurement, Co-axial current transformer, Semiconductor device characterization, Finite element analysis. The use of a co-axial current transformer (CCT) is an interesting choice for pulsed measurement of current through power devices during switching transients. The CCT is used to reflect current for convenient external measurement with minimal insertion impedance in the critical power circuit. This paper analyzes the characteristics of the CCT and explains how it can be integrated into test setups for both press-pack and module packages. Finite element techniques are applied to the study of the CCT to obtain detailed electrical and magnetic characteristics. Current distribution in the primary and secondary circuits, flux densities and insertion inductance and resistance are among the design information that can be obtained through finite element analysis. Analytical and numerical results are obtained for the proposed CCT that is integrated in test setups for MTO thyristors (press-pack) and HVIGBT (module) characterization. N.H. Kutkut, D.M. Divan, D.W. Novotny
1999-010 010 Advances in Electric Drive Control. Invited keynote paper in Proc. of IEEE International Electric Machines and Drives Conference '99, Seattle, WA, May 9-12, 1999, pp. 9-18. Advances in electric drive control which have shown significant practical advantages over the previously existing technology include physics-based state variable controls design, state observer design for sensor replacement, disturbance input decoupling design, selfsensing (sensorless) control, region-based fuzzy logic and structured neural networks. This paper discusses the design methods underlying their use. K. Fischer, K. Shenai
1999-011 011 An Active Gate Drive with Three-Stage Control and Fast Protection for High Power IGBTs EPE Conf. Rec. Lausanne, Switzerland. September 1999. V. John, B.-S. Suh, T.A. Lipo
1999-013 013 Novel Dual-Excitation Permanent Magnet Vernier Machine IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 4. pp. 2539-254 A novel Dual-Excitation Permanent Magnet Vernier Machine; DEPMVM, which has the feature of high torque at low speed, is presented. This machine has two stators both inside and outside of a ring shaped rotor, and its coils are wound around the yokes. These special structures are adopted as a result of detailed investigations of the machines which make use of the socalled ‘magnetic gearing effect.’ A prototype machine of the DEPMVM is designed and fabricated, and its experimental results indicate the promising nature of the machine. A. Toba, T.A. Lipo
1999-014 014 The Effects of Saturation on Flux Angle Estimation for Sensorless, Direct Field Oriented Control of Induction Machines In Proc. of EPE Conf., Sept. 7-9, 1999, Lausanne, Switzerland. Induction motors, sensorless control, harmonics, field oriented control, measurements This paper analyzes sensorless, direct field oriented control techniques that use saturation-induced saliencies for the estimation of flux angle in induction machine drives. Flux angle estimation based on saturation-induced saliencies relies on the fact that there is a known relationship between the position of the saliency and the flux angle being estimated. This paper first introduces a simple technique for measuring the saliency position under all operating conditions. From these experimental results and theoretical analysis it is shown that the position of saturation-induced saliencies are not fixed relative to any single component of flux in the machine and move significantly with changes in the operating point. This movement of the saliency position relative to the desired flux angle must be modeled for correct, sensorless, direct field oriented control. M.L. Aime, M.W. Degner, N. Tice, R.D. Lorenz
1999-015 015 Rotating Methods for Analysis and Control for Smooth Torque and Self-Sensing Motion Control of Switched Reluctance Motor Drives. In Proc. of EPE Conf., Sept. 7-9, 1999, Lausanne, Switzerland. Switched Reluctance Drives, Vector Control, Electrical Machines This paper presents a novel method of modeling and control of a switched reluctance motor (SRM). It is shown that complex rotating vectors can be used to develop an equivalent form of the torque equation in the SRM. This equivalent form of the torque equation leads to an insightful development of a closed form solution of the currents necessary to produce smooth torque in an SRM given any rotor dependent inductance function. The concept of rotating vectors is also used for saliency based position estimation techniques. N. Nagel, R.D. Lorenz
1999-016 016 An Auxillary Zero State Synthesizer to Reduce Common Mode Voltage in Three-Phase Inverters IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 1. pp. 54-59. Common mode voltage produced by the modulation of three-phase power inverters creates significant amount of common mode conducted current in motor drives. As an alternative to inserting a large common mode choke to attenuate this common mode current, a modification to the inverter topology and the modulation strategy is proposed that can eliminate zero state components in common mode voltage produced by the inverter. With the proposed modification, it is observed that the inverter generates substantially low common mode voltage, thereby resulting in reduction of common mode current by several orders of magnitude. The topological structure, operating principles and performance characteristics are presented. A comparative evaluation of various alternatives studied in the literature to mitigate electromagnetic interference is also presented in the paper. M.D. Manjrekar, T.D. Lipo
1999-017 017 Comparison of Motion Control Loops for Industrial Applications In Proc. of IEEE, IAS Annual Tech. Conf., Phoenix, AZ, Oct. 3-7, 1999, Vol. 4, pp. 251999-2605. High-performance AC and DC industrial servodrives use standardized motion control algorithms. The algorithms are based on common feedback sensing methods (digital position measurement via encoders or resolvers) and a common assumption that the electromagnetic torque dynamics are substantially faster than the motion control dynamics desired. The vast majority of these motion control algorithms close the motion control loops in one of two ways: 1) an average velocity loop is cascaded with a position loop, or 2) multiple state variable loops are closed in parallel. If the state variable form is properly configured, the command tracking properties are virtually independent of the disturbance rejection properties. However, this controller would require a command for acceleration which is frequently not available. In this case some modified form of cascaded loop controller topology is often used. In this paper the alternative methods for this case are explored and tuning guidelines developed based on both simulation and laboratory results. G. Ellis, R.D. Lorenz
1999-018 018 Web Machine Coordinated Motion Control via Electronic Line-Shafting In Proc. of IEEE, IAS Annual Tech. Conf., Phoenix, AZ, Oct. 3-7, 1999, Vol. 1, pp. 300-306, and accepted for IEEE Trans. on Ind. Appl.*** Most current multi-axis web machine controllers are not designed to possess the inter-axis stiffness properties that were the inherent coordinating force in historical, mechanically coupled, “line-shafted” multi-axis web machines. As a result, these controllers cannot maintain coordination for all operating conditions. This paper presents the development of an "electronic line-shafting" control technique which serves to replicate and even improve on the historical, mechanical lineshafted properties. This technique was implemented on a five-axis filament winding machine to evaluate such control during periods where the drive was in torque limit, velocity limit, or simply responding to asymmetric load induced disturbances. The results demonstrate that the "electronic lineshafting" technique significantly improves the coordination, robustness and overall stability of multiaxis, web handling machines subjected to realistic physical limitations. Index Terms - Motion control, synchronized control, relative stiffness control R.G. Anderson, A.J. Meyer, M.A. Valenzuela, R.D. Lorenz
1999-019 019 Complex Rotating Vector Methods for Smooth Torque Control of a Saturated Switched Reluctance Motor In Proc. of IEEE, IAS Annual Tech. Conf., Phoenix, AZ, Oct. 3-7, 1999, Vol. 4, pp. 2591-2598. This paper describes novel complex rotating vector methods for calculating the air gap torque of a switched reluctance motor (SRM). These vector methods are used to derive a number of insightful methods for improving the smoothness of the SRM's air gap torque. The development covers both unsaturated as well as saturated SRM's. Theoretical methods are developed; alternative implementations of such rotating vector methods are described; and experimental results are included on a commercial, unsaturated SRM and on a commercial, saturated SRM with asymmetry. The results verify the capability of the proposed vector methods. N.J. Nagel, R.D. Lorenz
1999-020 020 Modeling of a Saturated Switched Reluctance Motor Using an Operating Point Analysis and the Unsaturated Torque Equation In Proc. of IEEE, IAS Annual Tech. Conf., Phoenix, AZ, Oct. 3-7, 1999, Vol. 4. pp. 2219-2226, and to appear in IEEE Trans. on Ind. Appl. in May/June 2000. Switched Reluctance Motor, Smooth Torque, Saturation Modeling, Co-energy This paper describes torque production in a saturated switched reluctance motor (SRM). The paper begins by deriving the equations for torque if the SRM is unsaturated. It then develops an operating point model for torque in a saturated SRM using the unsaturated form of the torque equation. This results in a methodology which makes the control algorithms applicable to either saturated or unsaturated SRMs N.J. Nagel, R.D. Lorenz
1999-021 021 Hybrid Multilevel Power Conversion System: A Competitive Solution for High Power Applications IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 3. pp. 1520-1527. Use of multilevel inverters is becoming popular in recent years for high power applications. Various topologies and modulation strategies have been investigated for utility and drive applications in literature. Trends in power semiconductor technology indicate a trade-off in the selection of power devices in terms of switching frequency and voltage sustaining capability. New power converter topologies permit modular realization of multilevel inverters using a hybrid approach involving Integrated Gate Commutated Thyristors (IGCT) and Insulated Gate Bipolar Transistors (IGBT) operating in synergism. This paper is devoted to the investigation of a hybrid multilevel power conversion system typically suitable for high performance, high power applications. This system designed for 4.16 kV, ??100 HP load comprises of a hybrid seven-level inverter, a diode bridge rectifier and an IGBT rectifier per phase. The IGBT rectifier is used on the utility side as a real power flow regulator to the low voltage converter and as a harmonic compensator for the high voltage converter. The hybrid seven-level inverter on the load side consists of a high voltage, slow switching IGCT inverter and a low voltage, fast switching IGBT inverter. By employing different devices under different operating conditions, it is shown that one can optimize the power conversion capability of entire system. A detailed analysis of a novel hybrid modulation technique for the inverter, which incorporates stepped synthesis in conjunction with variable pulse width of the consecutive steps is included. In addition, performance of a multilevel current regulated delta modulator as applied to the single phase full bridge IGBT rectifier is discussed. Detailed computer simulations accompanied with experimental verification are presented in the paper. M.D. Manjrekar, P. Steimer, T.A. Lipo
1999-022 022 A Novel Electric Machine Employing Torque Magnification and Flux Concentration Effects IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 1. pp. 132-139. An evolving family of electric machines using the Torque Magnification (TM) Principle has attracted increasing interest in recent years. In this paper the TM principle is described following the introduction of the Specific Torque Density concept. A TM machine with flux concentration effect is presented, and its working principle explained. The design considerations of the machine, which are common to any TM machine, are studied in detail. Test results taken on a hardware prototype machine prove the concept and make clear that the machine’s cost-effectiveness. D. Qin, R. Qu, T.A. Lipo
1999-023 023 Experimental and Finite Element Analysis of an Electronic Pole-Change Drive IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 2. pp. 914-921. The theory and modeling of an electronic pole-change drive for the purpose of extending the constant power speed range of a four-pole induction machine, has been previously reported. This paper presents verification of the power capability characteristics of the proposed drive through experimental implementation. An indirect field oriented controller is developed for the pole-change drive with the estimated rotor open circuit time constant and d-axis current commands dependent on the mode of operation. It is demonstrated that for a constant power load, the drive can operate at 6340 rpm in two-pole mode without exceeding either the voltage or current limits at 3600 rpm in four-pole mode. A finite element method is also utilized to examine the influence of magnetic saturation on the pole-change drive performance. The nature of the magnetic flux distribution and saturation progression is investigated in both four-pole and two-pole modes. The saturation induced inductance variation is also studied and its influence on the dq inductance matrix is quantified. M. Osama, T.A. Lipo
1999-024 024 Effects of the Internal Layout on the Performance of IGBT Power Modules COBEP. Foz do Iguassu, Brazil. September 1999. A. Consoli, F. Gennaro, V. John, T.A. Lipo
1999-025 025 Radial Force Characteristics of a Switched Reluctance Machine IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 4. pp. 2250-2258. The operation of a switched reluctance machine with eccentric rotor positions creates asymmetrical airgap flux distributions and results in unbalanced magnetic pull. This paper comprehensively investigates the static and dynamic radial force characteristics of an 18/12 switched reluctance machine with unbalanced operation. A powerful magnetic equivalent circuit (MEC) modeling approach is developed and allow fast and accurate force predictions with arbitrary excitation and position. The model calculates the instantaneous radial and tangential forces on the individual poles as well as the net forces on the rotor. The method is validated with finite element analysis (FEA) and against experimental results from a 12/8 machine. Static radial force characteristics are first developed. The MEC is then coupled with a time stepping algorithm to calculate the simultaneously varying electrical, mechanical, and magnetic variables for dynamic operation of the complete SR motor drive. Dynamic radial force behavior is examined, where parallel connected windings are found to naturally and significantly reduce the unbalanced magnetic pull. Variations of radial force with torque-speed operating point are also examined. N.R. Garrigan, W.L. Soong, C.M. Stephans, A. Storace, T.A. Lipo
1999-026 026 Application of MTO-thyristors in Current Stiff Converters with Resonant Snubbers IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 3. pp. 1871-1878, and in IEEE Transactions on Industry Applications, Vol. 37, Issue 2, March/April 2001, pp. 566-573. This paper addresses the impact of power devices switching characteristics on design and performance of pulse width modulated current stiff converter (CSC) topolopogies with resonant snubbers. The MTO thyristors were selected for this study due to their high voltage and current ratings, simplified gate drive circuitry, unity gain turn-off, greatly reduced storage time allowing higher switching frequencies, and reverse voltage blocking capability. The analysis presented in this paper is supported by experimental data obtained from a CSC commutation cell capable of re- producing all the commutation processes in the current stiff converter topologies with active resonant snubbers. Issues involved in the implementation of the commutation cell itself and MTO characteristics relevant for their operation in CSC topologies with resonant snubbers are addressed in. B.J. Cardoso-Filho, T.A. Lipo
1999-027 027 High Power Converters with Active Snubbers for Variable Speed Drive Applications COBEP. Foz do Iguassu, Brazil. September 1999. B.J. Cardoso-Filho, T.A. Lipo
1999-028 028 Genetic Algorithms for the Continuous Design Domain In Proc. of IEEE, Applied Neural Networks Conf., St. Louis, MO, Nov. 7-10, 1999, pp. 337-342. Genetic Algorithms. Learning accuracy, coding, enhanced genetic algorithms, engineering optimization, error minimization, evolutionary algorithm, exploration, feedforward neural networks, fitness function, genetic operators, global optimization, least squares fitting, neural networks – nonlinear function approximation, performance evaluation, probability density function, search heuristics, transformation. Generalization of genetic algorithms to continuous design domain has practical value for many applications where discrete design space leads to inefficient representation of the optimization problem at hand. Hence, based on the detailed analysis conducted on the basic operators of genetic algorithms, this paper introduces new genetic algorithms that operate in continuous design space. Consequently, the performances of the proposed algorithms are evaluated on the training problem associated with feedforward neural networks. M. Dolen, E. Kayikci, R.D. Lorenz
1999-029 029 General Methodologies for Neural Network Programming In Proc. of IEEE, Applied Neural Networks Conf., St. Louis, MO, Nov. 7-10,1999, pp. 155-160. Neurally based networks. Algorithms and training, estimation, feedforward neural networks, generalization error, least squares fitting, linear activation functions, manufacturing applications, mixed linear and nonlinear systems, neural network application, nonlinear system modeling, parallel implementations, parameter estimation, process modeling, pruning, sigmoid activation function, signal interpretation, supervised learning, system identification, validation and verification. This paper presents a general methodology to design neural networks by using a priori information on the process under study. The approach is especially useful to develop efficient neural networks for the applications where full-scale models are available but too complicated to implement them on conventional computer systems. The paper also illustrates the method’s application to a real-world problem on the prediction of cutting forces in ideal machining process. M. Dolen, R.D. Lorenz
1999-030 030 A New Boost Type Rectifier for a DC Power Supply with Frequent Output Short Circuit IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 2. pp. 1165-1172. This paper describes a new boost type rectifier. The proposed converter output dc capacitors do not discharge even in a load short circuit condition. When a load short circuit occurs, the capacitors become a floating state immediately. The stored capacitor energy is supplied to the load again as soon as the short circuit has been cleared. This feature satisfies the requirement of a dc power supply for a load with frequent output short circuits. The proposed converter has the characteristics of a simplified structure, a reduced cost, weight, and volume compared with conventional power supplies with frequent output short circuits. Experimental results are presented to verify the usefulness of the proposed converter. E.-C. Nho, I.-D. Kim, T.A. Lipo
1999-031 031 Toroidal Switched Reluctance Motor SMIC. October 1999. K.-B. Kim, B.-I. Kwon
1999-032 032 Rotor Design for Hyper Speed Permanent Magnet Motor SMIC. October 1999. K.-B. Kim, H. Yun
1999-033 033 Impact of Saturation and Inverter Cost on Interior PM Synchronous Machine Drive Optimization IEEE-IAS Conf. Rec. Phoenix, AZ. October 1999. Vol. 1. pp. 125-131. interior permanent magnet synchronous machine, magnetic saturation, design optimization, drive cost minimization This paper discusses cost-optimized interior permanent-magnet (IPM) synchronous machine drive designs and the impact that magnetic saturation and inverter cost have on their performance and design optimization. Cost-optimized designs for IPM machines and combined machine-inverter systems are compared for an automotive starter/alternator application. The optimization is performed twice, once with a linear lumped parameter model, and again using a nonlinear saturating model. The saturating model produces cost-optimized IPM machines that have lower saliency ratios, larger volumes, and more magnet material than the linear non-saturating designs, but the saturating model designs are electromagnetically realizable unlike the linear model designs. The inclusion of inverter cost in the drive cost optimization has a significant impact on the machine design, exchanging a larger and more expensive machine for lower power electronics costs made possible by reduced inverter current. E.C. Lovelace, J.H. Lang, T.M. Jahns
1999-034 034 Using Carrier Frequency Current Injection for the Estimation of Flux, Position, and Velocity in AC Drives In Proc. of Brazilian Conf. on Power Electronics, COBEP 99, Foz do Iguassu, Brazil, Sept. 19-23, 1999. The focus of this paper is on an analysis of position, velocity, and flux estimation in ac machines based on the injection of a carrier signal in addition to the fundamental excitation. Specifically the paper addresses two problems of carrier signal current injection: 1) the regulation of high frequency currents with current regulators of limited bandwidth (regulation of the carrier signals with zero steadystate error is necessary to avoid loss of spatial information), and 2) the extraction of the spatial information contained in the induced voltages. L.A.S. Ribeiro, M.W. Degner, F. Briz, R.D. Lorenz
1999-035 035 Decoupled Control of a 4-Leg Inverter via a New 4x4 Transformation Matrix In Proc. of PESC'99 Conf., Charleston, SC, June 28-July 1, 1999. Four-Leg (3-phase 4-wire) inverters are developed to power unbalanced / non-linear three-phase loads. A unique 4x4 decoupling transformation matrix is used that enables direct transformation between the four degree-of-freedom (DOF) leg-modulation space of the inverter and its corresponding 3-DOF output-voltage space. This is analogous to the well-known 3x3 "abc-qd" transformation developed for the 3-Leg inverter. Details of this new 4x4 "Quad" transform are provided, along with a depiction of the voltage-vectors produced. Advanced synchronous-frame control techniques are applied with this 4-to-3 "abcn-qdo" transform to create a UPS-style inverter with sinewave output. Experimental results for an 8.6 kVa prototype inverter are presented. M.J. Ryan, R.W. DeDoncker, R.D. Lorenz
1999-036 036 A Modified Single Phase Inverter Topology with Active Common Mode Voltage Rejection. IEEE-PESC Conf. Rec. Charleston, SC. June 1999. Vol. 2. pp. 850-854. This paper addresses the problem of common mode EMI reduction in single phase PWM inverters by means of active cancellation. A topological modification which balances the switching pattern of the inverter is made. Common mode voltage, which results chiefly from unbalanced switching is thus significantly attenuated. This attenuation translates into a substantial reduction in the size and cost of passive filtering components needed to comply with conducted EMI standards. The principles of operation and performance of the proposed topology are discussed in this paper. A. Rao, T.A. Lipo, A. Julian
1999-037 037 A Magnetic Relief Scheme for Four Pole Induction Motors Electrimacs Conf. Lisbon, Portugal. September 1999. pp. I-15 - I-2 M. Osama, T.A. Lipo
1999-038 038 Switching Angles and DC Link Voltages Optimization for Multilevel Cascade Inverters Electric Machines and Power Systems Conf. 1999. Q. Jiang, T.A. Lipo
1999-039 039 Determination of Simultaneous Available Transfer Capability (ATC) NAPS. San Luis Obispo, CA. October 1999. Interconnected power systems, Power system availability, Power system parameter estimate, Power system reliability, Power system security, Power transmission reliability, Simultaneous power transfer, Available transfer capability, ATC, ISO, Congestion, Deregulation. This paper proposes a novel fast computational method to determine the simultaneous power available transfer capability (ATC) in a power system. This method consists of a fast estimation algorithm and a constrained power flow iteration. The ATC limiting factors considered in the method are: line thermal limits, bus voltage limits, and generator reactive power limits. When combined with the first line contingency considerations, this method will give the fastest ATC computing. The feature of this method is that it uses only one steady state power flow result for the fast estimation algorithm. Without further time consuming power flow iterations, it is the fastest estimation algorithm available. Based on the fast estimation, with a few more constrained power flow iterations, precise ATC value can be obtained. This method can be used to improve the speed of many available ATC programs. Especially, it may be used in addition to the widely used DC power flow program or simply replace it to provide additional voltage and var information, since DC power flow generally ignore voltage or var problems. This method can help the independent system operator (ISO) to determine the validity of the bidding results in an open access deregulated electricity market when timely ATC information is very important. It can also help the power market participants to place bids strategically when congestion happens. R. Wang, R.H. Lasseter
1999-040 040 The Impact of Generation Mix on Placement of Static VAR Compensators IEEE Trans. on Power Delivery. July 1999. Vol. 14. No. 3. pp. 1018-1023. power system control, power system reliability, power system security, power transmission reliability, power semiconductor devices, static var compensator, SVC. This paper looks at the problem of placing Static Var Compensators to provide maximum transfer capability for all possible generation mixes. The margin to low voltage limit is one of the quantities used to determine power system transfer capability. A fast method for finding the location of SVC systems that will have the greatest impact on the low voltage margin will be shown. The IEEE 24 bus system will be used to demonstrate this method over a wide range of generation patterns. R.H. Lasseter, R. Wang
2000-001 001 Complementary Half Controlled Three Phase PWM Boost Rectifier for Multi-DC-Link Applications APEC. New Orleans, LA. February 2000. Vol. 1, pp. 494-500. The half controlled three phase pulse width modulated (HC3_PWM) boost rectifier has simpler and more robust structure compared to the full controlled three phase (FC3_) PWM boost rectifier (reduced switch count and shoot through free legs), and better performance compared to the diode rectifier (actively controlled dc link voltage and lower input current total harmonic distortion (THD)). One of the main drawbacks is its even harmonic input current distortion which may cause undesirable resonance problems. Other issues of concern are fairly large ac side inductance and the necessity of intentional lagging power factor current command to obtain reasonably low input current THD. This paper describes methods with which these problems can be handled for a certain type of applications by introducing complementary topologies of HC3_PWM boost rectifiers. Two types of complementary conguration, rectifier leg complementary and input transformer complementary, are introduced. The former comprises an emitter common and a collector common HC3_PWM boost rectifiers. The latter utilizes complementary polarity of the in- put transformer secondary windings. Application candidates are those which need multiple dc links, e.g. H-bridge multilevel inverter systems or some types of multidrive systems. Two control schemes for this rectifier are presented, viz. a) independent local control (ILC) and b) coordinated central control (CCC). ILC can lead to even harmonics cancellation with equally supplied loads by two dc links. CCC can reduce not only even harmonics but also non-triplen odd harmonics (5th, 7th, ...). In CCC, ac side inductor size can be reduced and no lagging power factor current command is necessary. In addition, CCC can handle load imbalance between two dc links to a certain extent. Power stage description, control principles, simulation results and experimental results are presented. J. Kikuchi, M.D. Manjrekar, T.A Lipo
2000-002 002 Experimental Verification of Induced Voltage Self-Excitation of a Switched Reluctance Generato IEEE/IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol 1, pp51-56. Switched reluctance machine does not have its own self-excitation capability. However, permanent magnets could be placed in various positions on the core of the switched reluctance machine to provide its excitation requirements during starting. This paper is devoted to the experimental verification of this new self-excitation principle. The complete power electronic controller for driving a self-excited switched reluctance generator as well as several different generator configurations have been implemented. Design details, operating principles and experimental results are presented. V. Nedic, T.A. Lipo
2000-003 003 A Novel Variable Frequency Three Phase Induction Motor Drive System Using Only Three Controlled Switches IEEE/IAS Conference Record. Rome, Italy. October 8-12, 2000. Vol 3, pp 1468-1473, and in IEEE Transactions on Industry Applications, Vol. 37, Issue 6, Nov/Dec 2001, pp. 1739-1745. This paper presents a novel variable frequency motor drive system for a three-phase induction machine. In this drive system, the machine is excited by unidirectional stator currents shaped and sequenced such that a rotating air gap flux is induced so that the machine can operate. Due to the unidirectional nature of the currents, an “inverter” that incorporates only three active, IGBT type switches, and three freewheeling diodes can synthesize them. The drive system requires an asymmetric induction machine that can easily be obtained by externally rewiring a motor with a dual wound stator. The inverter is supplied by a single-phase input via a voltage doubler diode rectifier; hence it can be operated with residential service. In this paper, theoretical control methods are presented and both simulation and experimental results are provided proving the validity of the proposed drive system. B.A. Welchko, T.A. Lipo
2000-004 004 Improved PWM Modulation for a Permanent-Split Capacitor Motor IEEE/IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol 3, pp 2004-2010. This paper first examines and compares several methods for producing a variable speed drive for the permanent split-capacitor (PSC) induction motor. Conventional modulation methods are compared using phasor diagrams and then an improved modulation scheme using a boost converter and a three-phase drive is proposed. The derivation of the required excitation waveforms for any arbitrary PSC machine as a function of the turns ratio _ is presented in addition to an expression for determining the amount of required DC Bus boost. Experimental and theoretical results are included to verify the analysis. E.R. Benedict, T.A. Lipo
2000-005 005 Experimental Evaluations of the Dual-Excitation Permanent Magnet Vernier Machine IPEC Conf. Rec. Tokyo. April 3-7, 2000. pp. 1884-1889. High-torque, Vernier Machine, Permanent Magnet This paper presents experimental evaluations of the Dual-Excitation Permanent Magnet Vernier Machine, a high torque at low speed motor which has been proposed by the authors. Through the experiments, it is verified that the rated torque of the prototype is 15.1Nm with the stator of 130mm-diameter and 60mm-axial length, which is about 1.5 times higher than the conventional permanent magnet machines of the same size. Cogging torque and torque ripple are confirmed to be very low. The experimental results agreed well with the design and analysis, except that the mechanical and iron losses become higher than expected. A. Toba, H. Ohsawa, Y. Suzuki, T. Miura, T.A. Lipo
2000-006 006 An Improved Weighted Total Harmonic Distortion Index for Induction Motor Drives OPTIM. Brasov, Romania. 2000. Vol. 2, pp 311-22. Harmonic Distortion, Total Harmonic Distortion, Weighted Harmonic Distortion, THD, WTHD, Harmonics, Pulse Width Modulation. The weighted total harmonic distortion (WTHD) is a commonly used expression to assess the quality of pulse width modulated (PWM) inverter waveforms. The WTHD weights the voltage harmonics inversely with its frequency. While this is adequate for some inductor type loads, the commonly employed induction motor load has important effects resulting from eddy currents in the rotor bars not incorporated in the WTHD. In this paper a new distortion index, the IMWTHD, is proposed to more accurately evaluate modulated inverter waveform quality for squirrel-cage induction motor loads. T.A. Lipo
2000-007 007 Electronic Line-Shafting Control for Paper Machine Drives Proc of IEEE IAS Pulp and Paper Industry Conference, Atlanta, June 19-23, 2000, pp. 106-112, and in Proc of IEEE IAS Annual Meeting, Oct. 8-12, 2000, Rome, Italy pp. 3475-3481, and in IEEE Transactions on Industry Applications, Vol. 37, Issue 1, Jan/Feb 2002, pp. 158-164. M.A. Valenzuela, R.D Lorenz
2000-008 008 Dual AC-Drive System with a Reduced Switch Count IEEE Trans. on Industry Applications. Vol. 37, Issue 5, September/October 2001. pp. 1325-1333. A dual CRPWM VSI based on multiple two-phase PWM inverters, also called a B4 topology, requiring a dual three-phase drive system with reduced switch count is proposed. The drive utilizes a total of only eight switches to produce two sets of three-phase sinusoidal output currents. This new scheme minimizes the single-phase current flow through the DC-link capacitors, which is a common problem in reduced switch count topologies. By controlling the phase and magnitude of the currents generated by each inverter it is possible to cancel out the single-phase current flow through the DC-link capacitors. The paper presents a mathematical model of the proposed dual motor drive system including a control strategy that minimizes the capacitor’s voltage variations and the single-phase current flow through the DC-link capacitors. In order to verify the performance of the proposed drive system, an application on traction of an electric vehicle is carried out. The simulation results show that the single-phase current flow through the DClink can be eliminated or minimized when the vehicle moves in a straight-line regime, turning regime, or slippage condition. E. Ledezma, B. McGrath, A.R. Munoz-Garcia, T.A. Lipo
2000-009 009 Providing Premium Power Through Distributed Resources Hawaiian International Conf. on Adv. Tech. January 2000. CD-ROM. The modern industrial facility depends on sensitive electronic equipment that can be shut down suddenly by severe power system disturbances. A large number of these disturbances on the power system are a result of line faults which can cause momentary voltage sags. This results in equipment malfunctioning and high restart cost. This papers describes the control of distributed resources as a solution to such problems. In particular the focus is on systems of distributed resources that can switch from grid connection to island operation without causing problems for critical loads. R.H. Lasseter, P. Piagi
2000-010 010 Re-Dispatching Generation to Increase Power System Security Margin and Support Low Voltage Bus IEEE Trans. on Power Systems. May 2000. Vol. 15, No. 2, pp 496-501 power generation dispatch, power system control, power system dynamic stability, power system reliability, power system scheduling, power system security, power transmission control, power transmission reliability This article proposes a new method to increase a power system's security margin and/or support its low voltage bus by re-dispatching generator outputs, using a normal vector found at a voltage collapse boundary or a low voltage boundary (LVB). This method uses the normal vector as an indicator to change the generation direction so that more power can be transferred before reaching a boundary of a critical limit such as the voltage collapse boundary or LVB, etc. The method has been tested in the simulation on several systems and shows predicted results. It can be applied to many practical power systems to enhance the system's security, or to increase the system's transfer capability. It also provides technical guidance for an open access transmission in a deregulated environment, when bidding results are shown as generation patterns. R. Wang, R.H. Lasseter
2000-011 011 An LVDC Industrial Power Distribution System Without Central Control Unit IEEE-PESC Conf Recs. Galway, Ireland. June 18-23, 2000. Vol. 2, pp. 979-984. This paper develops a scheme to control parallel connected, multiterminal dc power distribution system without the need of central control unit for fast communication. The described scheme utilizes superconductors on the dc bus and incorporates UPS properties with the ability to supply large passive loads than conventional UPS’s. A five terminal, mesh connected study system is used to demonstrate the basic characteristics of dc power distribution system such as the ability to ride through an ac system outrage. In the paper a simulation model of the study system is developed and the simulation results show that the proposed dc power distribution system has a high power quality performance. W. Tang, R.H. Lasseter
2000-012 012 A Novel Control Method for Input Output Harmonic Elimination of the PWM Boost Type Rectifier Under Unbalanced Operating Conditions APEC. New Orleans, LA. February 2000. Vol. 1. pp. 413-419, and in IEEE Transactions on Power electronics, Vol. 16, No. 5, September 2001, pp. 603-611. This paper presents a new control strategy to improve the performance of the PWM Boost Type Rectifier when operating under an unbalanced supply. An analytical solution for harmonic elimination under unbalanced input voltages is obtained resulting in a smooth (constant) power flow from ac to dc side in spite of the unbalanced voltage condition. Based on the analysis of the open loop configuration, a closed loop control solution is proposed. Simulation results show excellent response and stable operation of the new rectifier control algorithm. A laboratory prototype has been designed to verify the discussions and analyses done in this paper. Theoretical and experimental results show excellent agreement. Elimination of the possibility of low order ac and dc side harmonics due to unbalance is expected to materially affect the cost of dc link capacitor and ac side filter. The proposed method will be particularly useful in applications where the large second harmonic at the DC link may have a severe impact on system stability of multiply connected converters on a common link. A.V. Stankovic, T.A. Lipo
2000-013 013 Power Loss Reduction and Optimum Modulation Index of PWM Inverter with Voltage Booster for Permanent Magnet Synchronous Motor Driv IPEC Conf. Rec. Tokyo. April 3-7, 2000. Vol. 1, pp 147-152. K. Yamamoto, T.A. Lipo, K. Shinohara, Y. Sueyoshi
2000-014 014 Measuring, Modeling, and Decoupling of Saturation-Induced Saliencies in Carrier Signal Injection-Based Sensorless AC Drives. IEEE/IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol. 3, pp 1842-1849. The focus of this paper is the measuring, modeling, and decoupling of saturation-induced saliencies in carrier signal injection based sensorless control. First techniques for the measurement of saturation-induced saliencies are presented. The goal of these measurements is to provide useful information on the position and magnitude of the various saturation-induced saliencies. Using the results from several different experimental measurements, models are developed explaining the source and behavior of the saturation-induced saliencies. The paper concludes by presenting methods for decoupling the effects caused by the parasitic saturation-induced saliencies, eliminating the errors that they cause in rotor position or flux angle estimation. F. Briz, M.W. Degner, A. Diez, R.D. Lorenz
2000-015 015 An Industrially Useful Means for Decomposition and Differentiation of Harmonic Components of Periodic Waveforms IEEE/IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol. 2, pp. 1016-1023. This paper presents efficient methods to estimate the spectral content of (noisy) periodic waveforms that are common in industrial processes. The techniques presented, which are based on the recursive discrete Fourier transform, are especially useful in computing high-order derivatives of such waveforms. Unlike conventional differentiating techniques, the methods presented differentiate in the frequency domain and thus are quite immune to uncorrelated measurement noise. This paper also shows the theoretical relationship between the proposed methods and those of well-known resonant filters. M. Dolen, R.D. Lorenz
2000-016 016 Resonant Load Control Method for Industrial Servo Drives IEEE-IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol 3, pp 1438-1445. High-performance servo drives are often limited by mechanical load resonance. In this paper, seven methods of resonant-load control are compared for their ability to improve performance in the presence of a low-frequency (100 Hz) lightly damped resonance. Several of the methods are based on filtering the command signal; the remaining methods are based on signals acquired from an observer. Development of these methods is presented; each method is applied to a physical system and evaluated for effects on command response and dynamic stiffness. G. Ellis, R.D. Lorenz
2000-017 017 Component Rating Requirements for Wide Constant Power Operation of Interior PM Synchronous Machine Drives. IEEE-IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol. 3, pp. 1697-1704. Previous work has established that wide ranges of constant power operation can be achieved with interior permanent magnet (IPM) synchronous machine drives when the machine parameters meet or approach the critical condition Ym/Ld=Irated. Closer examination reveals that the machine parameters also play a pivotal role in determining the necessary ratings of the inverter and the machine to achieve any particular value of constant-power speed ratio (CPSR). The purpose of this paper is to methodically describe the impact of the IPM machine parameters on the inverter and machine ratings in order to clarify the dependencies and tradeoffs that are involved in achieving wide ranges of constant-power operation. The importance of maintaining the values of the IPM machine’s magnet flux linkage Ym and inductance saliency ratio x?(=Lq/Ld) close to the optimal constant-power design locus line is explained as a means of minimizing the inverter component overratings (i.e., cost). However, tradeoffs emerge between inverter and machine overrating factors that must be considered in the mprocess of minimizing the total system cost. T.M. Jahns
2000-018 018 An Integrated Architectural Framework for Power Conversion Systems IEEE-Int'l Workshop on Integrated Power Pack. Boston, MA. July 2000, pp 12-16. Advances in electric power conversion systems have generally lagged far behind the pace of advances in the field of digital signal electronic systems. This has been a result of the rich and complicated coupling that exist among various design variables and manufacturing processes used in power electronics. There are significant obstacles that defy scaling which hold back the progress of power electronic systems.This paper presents an integrated architectural framework capable of systematically overcoming these obstacles using a top-down conceptual approach. General principles of the proposed framework based on “Bricks and Buses” are presented along with a discussion of the details that constitute the framework. G. Venkataramanan
2000-019 019 Power Electronic Transformers for Utility Applications IEEE-IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol. 4, pp 2496-2502. A transformer is employed to perform several functions such as voltage transformation, isolation, noise decoupling and has been an indispensable component in power conversion systems. However, at low operating frequencies, it is one of the heaviest and the most expensive equipment in an electrical distribution system. The concept of realizing a small size “solid-state” transformer has been discussed for some time. A fairly straightforward approach to accomplish sizereduction in a transformer feeding a conventional rectifierinverter system is to introduce an isolated dc-dc converter in the dc link, isolation being provided by a high frequency transformer. So also, several topologies that employ ac-ac converters connected on primary and secondary sides of ahigh frequency transformer to reduce the size and weight of the magnetic core have been reported in literature. Such ac-ac converters need switches with bi-directional voltage blocking and current carrying capability, which are commonly realized with pairs of gate turn-off devices such as Insulated Gate Bipolar Transistors (IGBT). This paper explores the possibilities of employing ac-ac switched mode power converters in combination with reactive elements to realize a chopped ac link, thereby decreasing the required magnetic core size for voltage transformation and isolation. A primary advantage of this approach is that, the static power converter needs only six devices to implement a three-phase electronic transformer, which makes it an economical solution. Operating principles, magnetic design and other practical issues are discussed. Detailed computer simulations accompanied with experimental verification are presented in the paper. M.D. Manjrekar, R. Kieferndorf, Venkataramanan
2000-020 020 A Power Electronic Transformer (PET) Fed Nine-level H-Bridge Inverter for Large Induction Motor Drives IEEE-IAS Conf Recs. Rome, Italy. October 8-12, 2000. Vol. 4, pp. 2489-2495. This paper is devoted to the investigation of a 500 HP induction machine drive based on a nine-level 4.16 kV H-bridge inverter. Previous work in the area of controlling HBridge inverters at such power levels report enhancement in the performance of a conventional staircase modulation technique by employing optimization of switching angles to minimize voltage distortion. However, the dc link voltages of each level are typically held constant. Such a control scheme enables elimination of a maximum of three dominant harmonics (5th, 7th & 11th) to synthesize a given fundamental voltage with a nine-level waveform. Moreover, at lower modulation depths, the nine-level operation degenerates into seven or even fewer levels. This restricts the number of harmonics that can be eliminated to two (5th & 7th) or less. An alternative strategy to produce a required fundamental voltage with a nine-level waveform by controlling the dc bus voltages is presented in this paper. This control schemeenables elimination of four dominant harmonics (5th, 7th, 11th & 13th) over the entire range of operation. The required dc link voltage control is achieved by employing active power electronic transformers for isolation, thereby supplying varying ac voltage to the front-end rectifiers. Operating principles, spectral structure and design consideration are discussed. Computer simulations backed up by experimental results are presented in the paper. R. Kieferndorf, G. Venkataramanan, M.D. Manjrekar
2000-021 021 Unity Power Factor Single Phase AC Line Current Conditione IEEE-IAS Conf Recs. Rome, Italy. October 8-12, 2000. Vol. 4, pp. 2297-2304. Electronic equipment used for data processing typically feature a simple diode bridge rectifier at the front end of the power circuit. The rectifier, in conjunction with its capacitive filter is a nonlinear load and draws current with high crest factor and rich in harmonics, which cause power quality problems. Such problems have prompted the development of unity power factor rectifiers, which use active current shaping techniques. However, such unity power factor rectifiers have not found widespread application in commercial data processing equipment, mainly due to the absence of persistent problems related power quality and higher premium being placed in processor speed, memory size, etc. This paper presents an alternative approach to solve power quality problems in such scenarios, only when the problem becomes severe and causes persistent malfunction. A unity power factor line current conditioner based on a boost type ac to ac converter topology is proposed. The paper presents a detailed analysis of the evolution of the converter topology, operation, and design. Experimental results for a prototype converter are included. K. Chatterjee, Cabrera Venkataramanan, Loftus M., D.
2000-022 022 Air-Gap Flux Position Estimation of Inaccessible Neutral Induction Machines by Zero Sequence Voltage Conference Records for the Syposium on Power Electronics, Electric Machines, & Drives. Italy. July 2000. Iss B1, pp 1-6. A. Consoli, G. Scarcella, A. Testa, T.A. Lipo
2000-023 023 Switching Transients of Low Cost Two Speed Drive for Single-Phase Induction Machine CPES Power Electronics Seminar. Blacksburg, VA. September 17-19, 2000. pp 78-86. Heating, ventilating, air conditioning & refrigeration (HVAC&R) systems represent one of the largest potential applications for Adjustable Speed Drives (ASD’s). The focus of this work is to sudy the switching performance of a new alternative circuit topology. The drive is specifically aimed at applications that do not require continuous speed control and enables the machine to efficiently operate at two different speeds. The drive consists of front-end diode bridge followed by an inverter with four MOSFET or IGBT switches. A computer model is developed for the proposed adjustable speed induction motor. The simulation results of the currents, voltages, speed and torque are illustrated to show the dynamic performance and transient response of this adjustable speed induction motor during switching insants. L. Woods, A. Homaifar, F. Fatehi, M. Chomat, T.A. Lipo
2000-024 024 Parameter Identification for Induction machines by Continuous Genetic Algorithms IEEE Neural Nets Council & ASME. St. Louis, MO. Nov. 5-8, 2000, pp. 341-346. Genetic Algorithms. Enhanced genetic algorithms, nonlinear systems and modeling, nonlinear dynamic system, ordinary differential equations, system identification, system modeling, objective function, population, parameter estimation, state estimation, optimization, speed, sampling, power engineering applications, performance evaluation, monitoring. This paper presents an efficient parameter identification method for induction machines based on an enhanced genetic algorithm that operates on real-valued parameter sets. The paper also proposes an improved method for calculating the fitness function for the identification problem. It also evaluates the performance of the proposed technique on a number simulation and experimental studies. P.Y. Chung, M. Dolen, R.D. Lorenz
2000-025 025 Electric Machine Analysis and Simulation Wiley Encyclopedia of Electrical and Electronics Engineering, vol. 6 (313-324). T.A. Lipo
2000-027 027 Recurrent Neural Network Topologies for Spectral State Estimation and Differentiation IEEE Neural Nets Council & ASME. St. Louis, MO. Nov. 5-8, 2000, pp. 159-164. Neurally based networks. Fourier Transform, FFT, FFT limitations, recurrent neural network, feedforward neural network, filtering, FIR filter, signal processing, Signal-to-Noise ratio, linear activation functions, sigmoid activation function, mixed linear and nonlinear systems, neural network application, parallel implementations, power engineering applications, process monitoring. This paper presents three recurrent neural network topologies to estimate the spectral content of (noisy) periodic waveforms that are common in engineering processes. The presented structured networks, which are based on the recursive discrete Fourier transform, are especially useful in computing high-order derivatives of such waveforms. Unlike conventional differentiating techniques, the proposed networks differentiate in the frequency domain and thus are quite immune to uncorrelated measurement noise. M. Dolen, E. Kayikci, R.D. Lorenz
2000-028 028 Operations of the Dominant Harmonic Active Filter (DHAF) Under Realistic Utility Conditions IEEE-IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol. 4, pp 2135-2142. IEEE Trans on Ind. Appl. vol 37 no 4, Jul-Aug 2001, pp 1037-44. P.T. Chent, S. Bhattacharya, D. Divan
2000-029 029 Stochastic Optimal Power Flow: Formulation and Solution. IEEE-PES Summer Meeting, 2000. Vol1, pp. 237-242, 202-30 Lasseter, R.H., R. Wang. The Impact of Generation Mix on Placement of Static Var Compensators IEEE Trans. on Power Delivery. July 1999. Vol. 14, No. 3, pp. 1018-1023. Power Systems Deregulation, Power Market, Stochastic Optimal Power Flow, Uncertainty, Benders’ Decomposition, Price of Reserve, Contingency Screening Stochastic Optimal Power Flow (OPF) problem is formulated to solve the optimal dispatch problem with consideration of uncertainties in electric power systems. In this paper we explore this problem in details. Different forms of linear stochastic OPF problems have been derived with different uncertainties in electric power systems. Also we discuss the computation issues related to large power systems and its possible applications in deregulated power market. T. Yong, R.H. Lasseter
2000-031 031 Performance Characterization of MOS Turn Off Thyristors. IEEE-IAS Conf Recs. Rome, Italy. October 8-12, 2000. Vol. 5, pp. 2853-2858. Recently, power semiconductor devices that combine the technology of MOS turn-off and bipolar conduction have been introduced for operation at high voltage and high current levels. The MOS Turn Off thyristor (MTOTM) is a switching device based on the Gate Turn Off Thyristor. This paper is devoted to presenting the results from a study performed to examine the operating characteristics of the MTOTM. The study included experimental measurements of on-state properties and switching characteristics under snubberless hard switching. Turn off loss; device switching delay time, storage time, transition time and on-state losses are characterized. In addition to the experimental results, the paper also presents a brief review of operation of the device and the experimental procedure used in the study. M. Gutierrez, G. Venkataramanan, A. Moreira
2000-032 032 An Improved Modulation Strategy For a Hybrid Multilevel Inverter IEEE-IAS Conf. Recs. Rome, Italy. October 8-12, 2000. Vol 4, pp. 2086-2093. Multilevel cascaded and hybrid inverter systems conventionally use three level bipolar PWM for each individual inverter, with their carriers phase shifted to achieve maximum harmonic cancellation within each phase leg. This has been shown to give a harmonic performance equivalent to APOD modulation of a NPC multilevel inverter, when the switching frequencies are scaled to achieve the same number of overall switch transitions. In contrast, PD modulation of a NPC inverter is harmonically superior, because it places harmonic energy directly into the carrier harmonic for each phase leg, and relies on cancellation of this harmonic across phase legs as the line-to-line voltage is developed. Using this understanding, a new discontinuous modulation strategy is proposed for a hybrid inverter which achieves a similar level of improvement in lineto-line harmonics compared to conventional three level modulation of this type of inverter. B.P. McGrath, D.G. Holmes, M. Manjrekar, T.A. Lipo
2000-033 033 Comparison of (Non-Slotted and Slotted) Surface Mounted PM Motors and Axial Flux Motors for Submarine Ship Drives 3rd Naval Symposium on Electrical Machines, 2000. International Agean Conference on electrical Machines and Power electronics, Kusadasi, Turkey, June 2001 S. Huang, M. Aydin, T.A. Lipo
2000-034 034 A "Power-Mapping" Variable-Speed Contol Technique for a Constant-Frequency Conversion System powered by a IC Engine and PM Generator IEEE Industry Applications Society Conference Record, Annual Meeting, Rome, Italy, October 8 - 12, 2000, vol 4, pp 2376-82. A variable-speed power conversion system is considered where a Permanent Magnet Generator (PMG) driven buy an IC engine supplies power to an electronic inverter. The AC voltage from the PMG is typically diode-rectified into a DC link, which is utilized by the inverter to produce constant-frequency, constant-voltage output. These “Electronic Gensets” can be smaller, lighter and have higher performance than their fixedspeed counterparts with synchronous alternators under field control. Such attributes are attractive for mobile and stand-by power applications. The added flexibility of a variable-speed Genset system must be met with suitable techniques for directing the speed at which the engine should operate for a given electrical load. Constraints on torque, speed, and DC Link voltage must additionally be met. This paper reviews conventional methods, and presents a new technique utilizing the operating power of the system as an input to a power-speed “map” for the system to follow. Experiment results are included. M.J. Ryan, R.D. Lorenz
2000-035 035 The Future of Electric Drives: Where are we headed? IEEE PEVC Conference Record, London, UK, Sept 18-19, 2000, pp 1-6. A key dimension for the future of motor drives is to make them reliable, value-added parts of a system. Reliability of motor drives is far from a resolved issue. The failure of drives has been attributed to many causes, but one of the dominant ones in recent studies is "misuse" in the application. While this may not seem like a drives problem, it actually represents one of our biggest opportunities for value-added engineering of drives. In essence, future drives need to be designed to live and function despite ongoing abuse. This may seem trivial, but the resolution of such application specific problems has vexed even the best of drive suppliers. This research domain is not simply another application of neural networks or fuzzy logic. Instead it will rely on smart drive research engineers who develop drives such that they avoid operating conditions which are not compatible with sustained operation and continue doing their main function, despite their lack of full knowledge of the load. This address will begin to unfold a vision of this future set of challenges. R.D. Lorenz
2000-036 036 Sensorless, Drive Control Methods for Stable, High Performance, Zero Speed Operation Proc of EPE-PEMC Annual Conference, Sept. 5-8, 2000, Kosice, pp 1-1, 1-11. R.D. Lorenz
2000-037 037 Rotor Position Estimation For Permanent Magnet Synchronous Motor Using Saliency-Tracking Self-Sensing Method IEEE-IAS 2000, vol 1, pp 445-50. This paper presents an implementation of a position estimation method using a carrier signal injection and a single saliency machine model for permanent magnet (PM) synchronous machines. The method using rotating vector, carrier frequency excitation and heterodyning, tracking observers for position estimation is discussed. The experimental results for the case of a buried PM machine are shown in the paper. It was demonstrated that acceptable results could be obtained from the buried PM machine using the simplest, single saliency-tracking method. L. Wang, R.D. Lorenz
2001-001 001 IPM Synchronous Machine Drive Response to a Single-Phase Open Circuit Fault IEEE Applied Power Electronics Conference (APEC), Anaheim, CA, March 4-8, 2001. vol 1, pp 421-7. This paper investigates the steady-state and dynamic response of an interior permanent magnet (IPM) synchronous machine drive to a single-phase open circuit fault. This fault results in rotational electromagnetic asymmetry on both the stator and rotor, making it difficult to analyze using classical dq-transformation techniques. This paper presents a new dq synchronous-frame machine model that is capable of handling this highly asymmetrical fault condition, including the effects of q-axis magnetic saturation. Fault responses with two alternative post-fault control strategies are investigated: 1) opening all of the inverter switches so that the machine behaves as an uncontrolled generator (UCG), with the two unfaulted phases connected to the inverter dc link via the anti-parallel diodes; and 2) shorting the two remaining unfaulted phases together using the inverter switches. Results of this investigation show that the fault response is generally more benign using the UCG control strategy, with significantly lower phase currents and pulsating torque than corresponding values delivered using the phase-shorting strategy. B.A. Welchko, T.M. Jahns, S. Hiti
2001-002 002 Optimised Space Vector Switching Sequences for Mutilevel Inverters IEEE Applied Power Electronics Conference (APEC) 2001. Anaheim, CA, March 4-8, 2001. vol 2, pp 1123-9 B.P. McGrath, D.G. Holmes, T.A. Lipo
2001-003 003 Unity Power Factor Control of a Three-pole PWM AC/DC Converter Under Single-phase Input CPES Annual Meeting. Blacksburg, VA. April 22-25, 2001. Y. Suh, P.G. Albano, V. Tijeras, T.A. Lipo
2001-004 004 Electromagnetic Vibration and Noise Assessment for Surface Mounted PM Machines Power Engineering Society Summer Meeting, 2001, Vol. 3, pp. 1417-1426. S. Huang, M. Aydin, T.A. Lipo
2001-005 005 Optimum Design and 3D Finite Element Analysis of Non-slotted and Slotted Internal Rotor Type Axial Flux PM Disc Machines Power Engineering Society Summer Meeting, 2001, Vol. 3, pp. 1409-1416. M. Aydin, S. Huang, T.A. Lipo
2001-006 006 Low Noise and Smooth Torque Permanent Magnet Propulsion Motors: Comparison of Non-slotted and Slotted Radial and Axial Flux Topologies Submitted to International Aegean Conference of Electrical Machines and Power Electronics, 2001. S. Huang, M. Aydin, T.A. Lipo
2001-007 007 Design and 3D Electromagnetic Field Analysis of Non-slotted and Slotted TORUS Type Axial Flux Surface Mounted Permanent Magnet Disc Machines IEEE International Electrical Machine and Drive Conference, June 17-20, 2001, Cambridge, MA. pp. 645-651. M. Aydin, S. Huang, T.A. Lipo
2001-008 008 A Generalized Control Method for Input-Output Harmonic Elimination for the PWM Boost Rectifier Under Simultaneous Unbalanced Input Voltages and Input Impedances IEEE PESC 2001. Vol. 3, pp. 1309-1314. A.V. Stankovic, T.A. Lipo
2001-009 009 Mechanical Design Considerations for Conventionally-Laminated, High-speed, Interior PM Synchronous Machine Rotors A Generalized Control Method for Input-Output Harmonic Elimination for the PWM Boost Rectifier Under Simultaneous Unbalanced Input Voltages and Input Impedances E.C. Lovelance, T.M. Jahns, T.A. Keim, J.H. Lang
2001-010 010 Adjustable-Speed Drive with Single-Phase Induction Machine for HVAC Applications IEEE Power Electronics Specialists Conference, 2001. Vol. 3, pp. 1446-1451. M. Chomat, T.A. Lipo
2001-011 011 Design Considerations for Single Phase Induction Motor Packaged Drives. IEEE International Electric Machines and Drives Conference, 2003. IEMDC'03. (Volume:2 ) J. Yao, J. Krase, T.A. Lipo
2001-012 012 Nonlinear Analysis and Experimental Result of Doubly Salient PM Generator. Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 2001. B. Sarlioglu, T.A. Lipo
2001-013 013 A Novel Control Strategy For the Rotor Side Control of a Doubly Fed Induction Machine IEEE IAS Chicago, IL. October 2001. pp. 1695-1702. D. Panda, E.L. Benedict, G. Venkataramanan, T.A. Lipo
2001-014 014 A New Control Technique for Achieving Wide Constant Power Speed Operation with an Interior PM Alternator Machine IEEE-IAS Chicago, IL. October 2001. pp. 807-814. J. Wai, T.M. Jahns
2001-015 015 Flexible dv/dt and di/dt Control Method for Insulated Gate Power Switches IEEE-IAS Chicago, IL. October 2001. pp. 1038-1045. S. Park, T.M. Jahns
2001-016 016 Minimization of Reverse Recovery Effects in Hard-Switched Inverters Using CoolMOS Power Switches. IEEE IAS Annual Meeting. Chicago, IL, USA, Oct 2001. pp. 641-647 Power MOSFETs, diodes, power semiconductor switches, pulse width modulated inverters, converters CoolMOS™ power switches offer appealingly low forward voltage drops in switching converter applications up to 800V, but the poor reverse recovery characteristics of their internal body diodes makes them difficult to use in hardswitching applications. A new technique based on synchronous rectification concepts, referred to as active channel freewheeling, is introduced as a promising approach for minimizing the diode reverse recovery effects. According to this approach, the reverse-conducting MOSFET channel is used to shunt the freewheeling current away from the body diode by gating the CoolMOS switches throughout their freewheeling intervals. Both simulation and experimental results are provided to explore the beneficial impact of this approach on the inverter's turn-on switching losses and peak device currents. The impacts of device terminal characteristics, temperature, and gating dead time on technique effectiveness are also examined. H. Kim, T.M. Jahns, G. VEnkataramanan
2001-017 017 Modeling and Evaluation of dv/dt Filters for AC Drives with High Switching Speed 9th European Conference on Power Electronics and Applications Graz, Austria, Aug 27-29, 2001. CD Rom. Adjustable speed drives, Converter machine interactions Recent advances in power electronic switching device technology have resulted in dramatic improvements and cost reduction of pulse-width modulated AC adjustable speed drives. Concomitant with the better performance enabled by the high switching speed and increased switching frequency they have also raised several concerns related to the consequences of high speed switching. One of these concerns is the over-voltage that appears at the motor terminals due to the impedance mismatch between the power cable and the motor. This paper develops accurate simulation models for power cables and motors that allow a better understanding of the over-voltage problem. The models can be readily implemented using computational tools like Matlab, thereby providing a convenient method to develop the best dv/dt filter solution for a particular drive. The power cable is modeled using several lumped-parameter segments of a lossy representation of transmission line. An algebraic analysis is developed to choose an adequate number of lumped-parameter segments. The number of required segment is function of the pulse rise time, cable characteristic parameters and cable length. Simulation results are presented analyzing the over-voltage problem for a wide range of pulse rise times and cable lengths for 1hp, 10hp and 100hp motors. The most important filter network solutions are investigated using the simulation program and an optimized design is performed for the RC Filter at the motor terminals. Experimental results verifying the validity of the model for the over-voltage analysis are presented. A.F. Moreira, T.A. Lipo, G. Venkataramanan, S. Bernet
2001-018 018 A Current Source PWM Inverter with Actively Commutated SCRs IEEE PESC, Vancouver, BC, Canada, June 2001. A new Pulse Width Modulated (PWM) Current Source Inverter (CSI) topology using one controlled switch and six SCRs is presented. The converter uses active commutation to realize pulse width modulation in a conventional SCR based CSI. Modulation techniques for the proposed CSI and switch control are developed. This topology is suitable for high performance, high power CSI applications. A. Bendre, I. Wallace, J. Nord, G. Venkataramanan
2001-019 019 High Frequency Modeling for Cable and Induction Motor Over-Voltage Studies in Long Cable Drives IEEE Industrial Application Society 36th annual Meeting. Chicago, IL, USA, Sep 30-Oct 5, 2001. pp. 1787-1794. High frequency simulation models for power cables and motors are the key tools that aid a better understanding of the over-voltage problem in PWM drives with long feeders. In this paper, the frequency responses of the cable and the motor windings are obtained experimentally and suitable models are developed to match the experimental results. Several lumped segments incorporating a lossy representation of the line is used to model the cable. The cable and induction motor models may be implemented using a computational tool such as Matlab, thereby providing a convenient method to analyze the overvoltage phenomena. Simulation and experimental results are presented for a typical 3 hp induction motor, showing the suitability of the developed simulation models. The most promising dv/dt filter networks are also investigated through simulation analysis, and a design approach based on a trade off between filter losses and motor peak voltage is proposed. Experimental results of a RC Filter at the motor terminals demonstrate the validity of the simulation models. A.F. Moreira, T.A. Lipo, G. Venkataramanan, S. Bernet
2001-020 020 A Unity Power Factor Three Phase PWM SCR Rectifier for High Power Applications in the Metal Industry IEEE IAS Annual Meeting Chicago, IL, USA, Oct 2001. pp. 968-975. A new thyristor current source rectifier that achieves unity power factor, low current THD and DC bus current and voltage control is presented. The rectifier is suitable for high power applications such as induction heating and DC arc furnaces. It combines a traditional six-pulse thyristor bridge and a dc chopper that together solve power quality problems such as poor power factor and flicker generation. This topology achieves low input current THD and dc power control without additional power factor correction equipment, harmonic trap filters, use of multiple pulse rectifiers, or high K-factor transformers. I. Wallace, A. Bendre, J. Nord, G. Venkataramanan
2001-021 021 Model Reference Current Control of a Unipolar Induction Motor Drive IEEE IAS Annual Meeting. Chicago IL, Sep 30-Oct 4, 2001. pp. 1807-1813. A control algorithm to yield the required current shaping control of a three active switch, three-phase unipolar drive system for an induction motor is derived in this paper. The method utilizes terminal voltage control through PWM to properly shape the phase currents. Phase voltages are calculated based on both the fundamental frequency and zero sequence steady-state equivalent circuits of an induction machine to achieve the desired speed and load set point. Since this method relies on characterizing the machine parameters, it does not require feedback of the phase currents, and therefore, drive systems using this method for this topology can eliminate three current sensors over traditional hysteretic current control methods. Both simulation and experimental results are included to verify the proposed terminal voltage control method on this potential low cost variable speed topology for integrated motorinverter products. B.A. Welchko, T.A. Lipo
2001-022 022 IPM Synchronous Machine Drive Response to Symmetrical and Asymmetrical Short Circuit Faults 9th European Conference on Power Electronics and Applications Graz, Austria, Aug 27-29, 2001. CD Rom. AC Machines, Adjustable speed drives, Converter control, Modeling, Permanent magnet motors A closed-form solution is presented for the steady-state response of interior permanent magnet(IPM) synchronous machines to symmetrical short circuits including the effects of q-axis magnetic saturation. Machine response to single-phase asymmetrical short circuits is also investigated. Experimental data is presented to verify predicted behavior for both types of short circuits. It is shown that single-phase asymmetrical short circuit faults produce more severe fault responses with high pulsating torque and a significant threat of rotor demagnetization. A control strategy that purposely transitions such faults into symmetrical three-phase short circuits can minimize the fault severity and associated demagnetization risks. Implications for the design of IPM machines with improved fault tolerance are discussed. B.A. Welchko, T.M. Jahns, W.L. Soong, J.M. Nagashima
2001-023 023 Design and Experiments of a Novel Axial Flux Circumferential Current Permanent Magnet (AFCC) Machine with Radial Airgap IEEE IAS Chicago, Sep 30-Oct 5, 2001. pp. 1989-1996. J. LUo, S. Huang, S. Chen, T.A. Lipo
2001-024 024 A Continuous-Time Observer to Estimate Electrical Parameters of Induction Machines IEEE IAS, Chicago, IL, Sep 30 - Oct 5, 2001. pp. 259-265. This paper introduces a new observer topology to estimate the electrical parameters of induction machines. The observer utilizes classical Least Mean Squares principle of adaptive control and filtering theory. On-line parameter estimation techniques generally require the use of a special test setup or occasionally make unrealistic assumptions such as the availability of the entire state vector measurements. The significance of the proposed observer is its independence of special equipment/drives and its ability to estimate major IM parameters, together with unobservable machine states like rotor flux linkages. J. Chung, M. Dolen, H. Kim, R.D. Lorenz
2001-025 025 Comparative Evaluation of Flux Observers in a High Performance Drives Testbed EPE 2001 Conference, Aug 27-29, Graz, Austria. CD Rom. AC machines, Vector Control, DSP. This paper presents a comparative evaluation of flux observers for state-of-the-art, direct field oriented induction machine drives. The implementation is part of the development of a high performance drive testbed. Included in the full paper is the development of the overall testbed layout, test and measurement systems embedded in the testbed, as well as the control topology. E. Carter, A. Bellini, D. Murdock, R.D. Lorenz
2001-026 026 Encoderless IPM Drive System for EV/HEV Propulsion Applications EPE 2001 Conference, Aug. 27-29, Graz, Austria. CD Rom. <> <> <> <> <><> <> This paper presents an accurate and robust method of estimating rotor position for an IPM (Interior Permanent Magnet) drive system for EV/HEV (Electric Vehicles/Hybrid Electric Vehicles) applications. The importance of encoderless technique for electric propulsion drives has been highlighted in the present study. Stability and dynamic behavior of the position estimation is critical in consumer-oriented traction applications. The paper provides experimental results, which demonstrate an excellent performance of the proposed control algorithm. The goal of this paper is to present an encoderless (or position sensorless) control method for EV/HEV propulsion drives which works over the entire torque-speed range including zero mechanical speed. The method combines two rotor position estimation techniques to fully cover both low (incl. zero) and high-speed ranges. Experimental results demonstrate excellent performance. N. Patel, T. O'Meara, J. Nagashima, R. Lorenz
2001-027 027 Startup and Commissioning Procedures for Electronically Line-Shafted Paper Machine Drive 2001 IEEE Pulp & Paper Conference, June 18-21, 2001, Portland, OR. pp. 233-240. Electronic line-shafting control has demonstrated very promising features when applied to paper machine drives. To apply this new control methodology, it is necessary to develop a starting procedure for each individual section and a method for setting the parameters of the virtual line-shaft drive and in-shafts. This paper proposes and evaluates startup and commissioning procedures for electronically line-shafted paper machine drives. The procedure for acceleration of the individual sections is implemented using virtual, variable-ratio gearboxes that emulate the physical clutches and conical pulleys used in the era of line-shafts. System stiffness is implemented using virtual in-shafts with active damping. Evaluation shows that the proposed virtual clutch/conical pulley assembly and active damping allow smooth acceleration of each section and maintain well behaved response during load disturbances for all operating conditions, even with different number of sections effectively connected. M.A. Valenzuela, R.D. Lorenz
2001-028 028 Distance Learning: World-Wide Graduate Engineering Education Compatible with Dynamic Change E=TeM2 Conference sponsored by EPE, Liege, Belgium, March 14-15, 2001, pp 1-10. Distance learning, if properly formed, can have a strategic capability to enable dynamic change and bond industry with academia in a highly synergistic relationship. The examples are taken from the last ten years of experience with this methodology at the University of Wisconsin-Madison as a strategic element of the high successful graduate research industrial consortium, the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC). R.D. Lorenz
2001-029 029 Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines IEEE IAS Chicago, IL, Sep 30-Oct 4, 2001. pp. 133-139. A new, deadbeat type of direct torque control is proposed, analyzed and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods. B.H. Kenny, R.D. Lorenz
2001-030 030 Encoderless IPM Traction Drive for EV/HEV's IEEE IAS Chicago, IL, Sep 30 - Oct 4, 2001. pp. 1703-1707. This paper presents an accurate and robust method of estimating rotor position for an IPM drive system for EV/HEV applications. The importance of position sensorless technique for electric propulsion drives has been highlighted in the present study. Stability and dynamic behavior of the position estimation is critical in real world applications. The paper provides experimental results, which demonstrate the excellent performance of the proposed control algorithm. The goal of this paper is to design, implement and successfully demonstrate a sensorless control algorithm for EV/HEV propulsion drive system which works over the entire torquespeed range including zero mechanical speed achieved by combining two rotor position estimation methods for low and high speed ranges. N. Patel, T. O'Meara, J. Nagashima, R. Lorenz
2001-031 031 Robotics and Automation Applications of Drives and Converters Proc. of IEEE Special Issue on Power Electronics, Vol. 89, No 6, June 2001. FEPPCON IV, Italy May 26-30, 2001. power electronics reliability, operation in limits, dynamic range limits, thermal control of semiconductors, sensorless control, self-sensing methods, precision motion control, dynamic stiffness, direct drive motors, contactless power delivery The current design limits of power electronics have a significant effect on robotics and automation applications of drives and converters. This paper treats the major design limits that include dynamic range, reliability of power electronics, precision engineering and reliability, productivity and reliability, and drive motion control standards. For each of these limits, the paper identifies and discusses the salient issues and relates them to promising new technologies and thus to the future challenges in power electronic systems. R.D. Lorenz
2001-032 032 Practical Issues and Research Opportunities when Implementing Zero Speed Sensorless Control ICEMS 2001, Shenyang, China, Aug 18-20, 2001. It is well accepted that drives require knowledge of rotor and flux linkage positions to precisely control torque and motion at all speeds including zero and near zero. In industrial applications the rotor position sensor is the standard solution. However, in the rapidly emerging automotive and aerospace applications the harsh environment (temperature, humidity, chemicals, and vibration) can easily cause failure of the sensor connectors, cables or sensor components. Such failures are unacceptable. Furthermore, the weight and cost penalty associated with mechanically protecting the sensor, sensor connector, and sensor cabling is a significant disadvantage. Thus, true sensorless operation through the power leads is fast becoming a requirement. This paper will focus on practical implementation and research issues for sensorless, high performance, zero and near zero speed, motion control. R.D. Lorenz
2001-033 033 Implementation Issues Affecting the Performance of Carrier Signal Injection Based Sensorless Controlled AC Drives IEEE IAS Chicago, IL, Sep 30 - Oct 4, 2001. pp. 2645-2652. This paper assesses and analyzes the practical implementation issues affecting the performance of carrier signal injection based sensorless control methods for AC drives. Included in this assessment and analysis are the following topics: selection of the carrier signal frequency and magnitude; the nonlinear behavior of pulse-width modulation and power electronics; and the signal processing required for the estimation, including analog filtering, sampling, and analog-todigital conversion. Variations in the characteristics and behavior of the saliency used for the estimation as a function of the machine's design and operating point are also addressed. The influence that each of these topics has on the robustness and accuracy of the estimate is discussed. Finally, conclusions are drawn on how the negative effects can be minimized and the performance of the estimation improved. F. Briz, M.W. Degner, J.M. Guerrero, A. Zamarron, R.D. Lorenz
2001-034 034 Static and Dynamic Behavior of Saturation-Induced Saliencies and Their Effect on Carrier Signal Based Sensorless AC Drives IEEE IAS Chicago, IL, Sep 30 - Oct 4, 2001. pp. 1210-1217. This paper analyzes the origin and the behavior of saturation-induced saliencies in induction machines, and their influence on carrier signal injection based sensorless techniques. The modeling of saturation-induced saliencies is necessary for the estimation of flux position, while the minimization of their influence is desired for the estimation of rotor position. Specifically focusing on rotor position estimation, there are two ways to achieve this minimization, the first being the use of a machine design that reduces the magnitude of the undesired saturation-induced saliencies and the second being the compensation in the estimator of the undesired saturationinduced saliencies. The modeling of saturation-induced saliencies, not only statically, but also dynamically, i.e. when the operating point of the machine changes, will be addressed by this paper. F. Briz, M.W. Degner, A. Diez, R.D. Lorenz
2001-035 035 Investigation of Interior Permanent Magnet Offset-Coupled Automotive Integrated Starter/Alternator IEEE IAS Chicago, IL, Sep 30 - Oct 4, 2001.pp. 429-436. W.L. Soong, N. Ertugrul, E.C. Lovelace, T.M. Jahns
2001-036 036 Three Phase PWM Boost-Buck Rectifiers with Power Regenerating Capabilit IEEE IAS Chicago, IL, Sep 30 - Oct 4, 2001. pp. 308-315. IEEE Industrial Application Society 36th Annual Meeting, Chicago, IL, Sept. 30-Oct 5, 2001, pp. 308-315. J. Kikuchi, T.A. Lipo
2001-037 037 Rotor Position Estimation for Permanent Magnet Synchronous Motor Using Saliency-Tracking Self-Sensing Method In Proc.of IEEE IAS Annual Meeting, Oct. 8-12, 2000, Rome, Italy, pp. 445-450. L. Wang, R.D. Lorenz
2001-038 038 Load torque estimation for spindle drives using structured neural network topologies In Proc.of IEEE ANNIE 2001, St. Louis, Nov. 4-7, 2001. pp. 1007-1012. M. Dolen, E. Kayikci, R.D. Lorenz
2001-039 039 Comparative performance analysis of structured neural networks and observers for CNC feed drive disturbance force estimation In Proc.of IEEE ANNIE 2001, St. Louis, Nov. 4-7, 2001. pp. 1001-1006. This paper presents a structured neural network for feed drives of CNC vertical machining centers to accurately estimate machining forces. The estimation performance of the network is evaluated through a detailed simulation study. The accuracy of a Luenberger-type disturbance observer, which is a feasible alternative to the network, is compared to that of the network. With similar system parameter estimates for both methods, the network is found to be considerably more accurate than the observer. M. Dolen, E. Kayikci, R.D. Lorenz
2001-040 040 Torque quality and comparison of internal and external rotor axial flux surface-magnet disc machine Industrial Electronics Society, 2001. IECON '01. The 27th Annual Conference of the IEEE, Volume 2, 29 Nov.-2 Dec. 2001 Page(s):1428 - 1434 vol.2. Industrial Electronics, IEEE Transactions on Volume 53, Issue 3, June 2006 Page(s):822 - 830 M. Aydin, S. Huang, T.A. Lipo
2001-041 041 Adjustable-Speed Single-Phase IM Drive with Reduced Number of Switches Chomat, M., T.A. Lipo IEEE-IAS Annual Meeting, Chicago, IL, Sept 30-Oct 5, 2001, Vol. 1, pp. 1800-1806.. IEEE Transactions on Industry Applications, vol.39, issue. 3, may-June.2003, pp.819-825. A novel low-cost single-phase induction machine drive containing only two controlled solid-state switches is presented. The drive is intended for an HVAC type of application requiring variable-speed operation. An experimental drive based on the proposed setup has been developed and built to verify its practical viability and properties. The paper presents the results obtained from an investigation into this new topology and discusses the properties and characteristics of the drive for the entire speed range from 0 to 60 Hz. M. Aydin, S. Huang, T.A. Lipo
2002-001 001 Air-Gap Flux Position Estimation of Inaccessible Neutral Induction Machines by Zero-Sequence Voltage Conference Records for the Symposium on Power Electronics, Electric Machines and Drives, Italy, July 2000, Issue B1, pp. 1-6. Also, Electric Power Components and Systems 2002, Vol. 30, No. 1, pp. 77-88. T.A. Lipo, A. Consoli, G. Scarcella, A. Testa
2002-002 002 Power Conversion Challenges with a Multidisciplinary Focus IEEE IAS PCC Osaka, April 2-5, 2002. solid geometric design, concurrent design, power electronics reliability, operation in limits, dynamic range limits, thermal control of semiconductors, thermalmechatronics Power electronics is a key enabling technology in modern power conversion. However, there are rather substantial challenges which limit its more widespread acceptance. The challenges covered in this paper relate to fundamental design paradigms that could be changed via a true multidisciplinary focus. Amongst such major challenges are 1) the need for solid geometric concurrent design methods, 2) the need for enhanced dynamic range consistent with applications, 3) the need for sustained operation in physical limits without shutdown, and 4) the need for integrated sensing methodologies. For each of these challenges, the paper identifies and discusses the salient issues and relates them to promising new multidisciplinary technologies in power electronic systems. R.D. Lorenz
2002-003 003 Sensorless Tension Control In Paper Machines IEE IAS Pulp & Paper Industry Conference, Toronto, June 17-20, 2002. IEEE IAS Pulp & Paper Industry Conference, Toronto, June 17-20, 2002. Proper operation of the dry-end of a paper machine requires some type of sheet tension control. Present systems use either indirect speed control based schemes, or sensor based direct tension control utilizing load cells or swing rolls. The indirect schemes are inadequate for most newer machines, and both types of the commonly used sensor based schemes are invasive, expensive, require either special, or extra rolls, and add complexity to the sheet runs. This paper proposes and evaluates sheet tension estimation using only conventional motor and control signals, present in all newer drive controllers, integrated into a process model observer. This observer-based approach eliminates the need for the invasive tension transducers, and may also be used to replace the inaccurate indirect speed control schemes. A. Valenzuela, J. Bentley, R.D. Lorenz
2002-004 004 Generalization of Linear Control Tools for Complex Vectors IFAC Conference, Barcelona, July 21-26, 2002. IFAC Conference, Barcelona, July 21-26, 2002. Current regulators, electric machines, complex variables, inverter drives. Complex vectors have established them selves as powerful tool in the modeling and control of three-phase electrical AC systems. Generalization of classical control tools like root locus and frequency response function for the case of complex variables will be shown in this paper to provide tremendous insight in the analysis and design of high performance, three-phase current regulators for AC systems. Copyright © 2002 IFAC F. Briz, A. Diez, R.D. Lorenz
2002-005 005 A Study of Sensorless Control of Induction Motor at Zero Speed Utilizing High Frequency Voltage Injection 10th International Power Electronics and Motion Control Conference EPE-PEMC 2002, September 9-11, 2002, Cavtat & Dubrovnik, Croatia. Sensorless control, induction motors, measurements, modelling A detailed investigation of sensorless control of induction motor at zero and very low speed based on injection of a pulsating high frequency voltage signal is presented. A sensing technique used to measure air gap flux position in a squirrel cage induction motor is based on the secondary effect of magnetic spatial nonlinearity caused by saturation of the stator laminations. The physical insight into the motor excited by high frequency test signals is given by means of experiment and finite element simulation. It is shown that it is possible to control the motor torque using the proposed technique, but with low bandwidth and with the necessity to perform special tests and measure special characteristics for each new motor prior to utilization. D. Drevensek, D. Zarko, T.A. Lipo
2002-006 006 CPPM Machine: A Synchronous Permanent Magnet Machine with Field Weakening International Agean Conference on Electrical Machines and Power Electronics, Turkey, June 2001 PM machine, Field Weakening, Design PM machines Due to its particular configuration, the Consequent Pole Permanent Magnet (CPPM) machine allows one to easily control the airgap flux in a wide range so that the power capability of the machine is increased over a wide speed range. Two components of the flux, one -almost constant- coming from the permanent magnet located on the rotor surface of the machine, and the other –variable- coming from a field winding located in the middle of the stator, converge in the airgap characterizing the level of excitation of the machine. The field winding -when a variable DC current is injected- provides an adaptable level of excitation inboth positive and negative directions respect to the PM magnetization. In this manner, control of the airgap flux can be obtained with a reduced amount of field MMF. A prototype using this configuration has been built and experimental results show that with 10% of the phase MMF it is possible to vary the flux in a range over +/-40%. J.A. Tapia, T.A. Lipo, F. Leonardi
2002-007 007 Consequent Pole Permanent Magnet Machine with Field Weakening Capability Intl. Electrical Machines and Drives Conf. (IEMDC), Cambridge MA, June 17-20, 2001, pp. 126-131. J.A. Tapia, F. Leonardi, T.A. Lipo
2002-008 008 A Novel Soft-Switching Inverter with ZCS-ZVS Features IEEE Power Electronics Specialists Conference, Vancouver, June 17-21, 2001. pp. 1141-1146.** J. Yao, T.A. Lipo
2002-009 009 TORUS Concept Machines: Pre-Prototyping Assessment for Two Major Topologies Conf. Rec. IEEE IAS Annual Meeting, Chicago, Oct. 2001, pp. 1619-1625. Two different external-rotor-internal-stator TORUS type axial flux PM machines can be derived based on the direction of the flux. In the first type of the TORUS machine, magnet driven flux enters stator and travels circumferentially along the stator core while in the second type the flux enters the stator and travels axially along the machine axis of rotation. The major differences between the two topologies are the direction of the magnet driven flux, the winding arrangement and the thickness of the stator yoke. In this paper, the sizing equations are derived for both types of TORUS machines. Based on the sizing analysis, optimum design is achieved for minimum ripple torque and maximum torque density. Furthermore, Finite Element Analysis (FEA) of both TORUS structures are investigated to get an insight in 3D field distribution, flux directions and paths in different parts of the machines for different load conditions. Minimization of the cogging and ripple torque components of the TORUS concept machines are displayed using 3D FEA for the insight in pulsating torques, ripple torques and cogging torques. Finally the comparison of the TORUS topologies are made in terms of flux densities, cogging and ripple torques and the results are illustrated in the paper. S. Huang, M. Aydin, T.A. Lipo
2002-010 010 Torque Quality Assessment and Sizing Optimization for Surface Mounted Permanent Magnet Machines Conf. Rec. IEEE IAS Annual Meeting, Chicago, Oct. 2001, pp. 1603-1610. Torque quality assessment and optimization methods are presented in this paper. General purpose sizing equations are obtained and sizing optimization of the slotless TORUS machine is shown for maximum power density or efficiency points. For pulsating torque analysis, general instantaneous electromagnetic torque equation and torque ripple factor (TRF) analysis are carried out. Besides, stator winding distribution factor and rotor PM skew factor, excitation field form factor to indicate the excitation field harmonics, open slot factor to indicate the slot effect based on the calculation of airgap permeance are introduced for non slotted and slotted axial flux surface mounted PM machines. Based on the above analysis, optimum design can be achieved for minimum ripple torque. On the other hand, cogging torque can be canceled using non-slotted structure. Slotless TORUS machine is used as a sample application for the torque ripple minimization in the paper. Furthermore, 2D and 3D Finite Element Analysis (FEA) of both non-slotted and slotted surface mounted PM TORUS type (axial flux external rotor internal stator) structure, AFIR type (axial flux internal rotor external stator) structure and RFSM (radial flux internal rotor external stator) type structures are investigated for the insight in pulsating torques, ripple torques and cogging torques. The results obtained from both TRF analysis and 2D/3D FEA are illustrated in the paper. S. Huang, M. Aydin, T.A. Lipo
2002-011 011 A Novel Matrix Converter Topology with Simple Commutation Conf. Rec. IEEE IAS Annual Meeting, Chicago, Oct. 2001, pp. 1749-1754. Matrix converter is very simple in structure and has powerful controllability. However, commutation problem and complicated PWM method keep it from being utilized in industry. This paper discloses a novel matrix topology with advantages over the usual matrix converter topology. Firstly, it has the same performance as a conventional matrix converter in terms of voltage transfer ration capacity, four quadrant operation, unity input power factor, no DC capacitor and pure sine waveforms with only high order harmonics in both line and load side. Secondly, the PWM method utilized at conventional inverter can be used, which can largely simplify its control complexity. Thirdly, all the switches at line side turn on and turn off at zero current; the converter does not have any commutation problems as required by the conventional matrix converter. Theoretical analyses and simulation results are provided to verify its feasibility. L. Wei, T.A. Lipo
2002-012 012 Torque Density Improvement in a Six-phase Induction Motor with Third Harmonic Current Injectio Conf. Rec. IEEE IAS Annual Meeting, Chicago, Oct. 2001, pp. 1779-1786. Industrial drives, Induction machine analysis and design, Six-phase drives. The use of six-phase induction motor for industrial drives presents several advantages over the conventional threephase drive such as improved reliability, magnetic flux harmonic reduction, torque pulsations minimization and reduction on the power ratings for the static converter. For these reasons, sixphase induction motors are beginning to be a widely acceptable alternative in high power applications. A typical construction of such drives includes an induction machine with a dual threephase connection, where two three-phase groups are spatially shifted thirty electrical degrees, a six-leg inverter and a control circuit. By controlling the machine’s phase currents, harmonic elimination and torque ripple reduction techniques could be implemented. This paper describes a technique of injecting third harmonic zero sequence current components in the phase currents, which greatly improves the machine torque density. Analytical, finite element and experimental results are presented to show the system operation and to demonstrate the improvement on the torque density. R. Lyra, T.A. Lipo
2002-013 013 Pulse Width Modulated Series Compensator IEE Proceedings, Generation, Transmission and Distribution, Vol. 149, No. 1, January 2002., pp. 71-75 G. Venkataramanan, B.K. Johnson
2002-014 014 Chapter 15 - AC Motor Speed Control. Department of Electrical and Computer Engineering, University of Wisconsin-Madison, February 2002. T.A. Lipo, K. Jezernik
2002-015 015 Matrix Converter Topologies with Reduced Number of Switches IEEE PESC Conference, Queensland, Australia. June 23-27, 2002.** A direct AC-to-AC converter commonly termed a matrix converter has a simple structure and many attractive features. However, the complexity of its conventional PWM strategy is prone to commutation failure, which is a factor that keeps it from being utilized in industry. This paper focuses on several alternative dual-bridge matrix topologies which do not possess this problem. First, these converters have the same characteristics as a conventional matrix converter, such as fourquadrant operation, unity input power factor, no dc-link capacitor, and high quality voltage/current waveforms. Second, the number of switches can be reduced thus reducing the cost. Third, the switches on the line side can turn on and off at zero current, they do not have any difficult commutation problems. Lastly, the complexity of the clamp circuit in these topologies can be greatly simplified thereby further reducing the cost. This paper introduces several topologies with reduced number of switches and analyzes the characteristics of this converter family.Simulation and experimental results of a 9-switch topology are provided to verify its feasibility. L. Wei, H. Chan, T.A. Lipo
2002-016 016 Thermal Analysis of Multi-Barrier Interior PM synchronous Machine using Lumped Parameter Model 2002 International Conference on Electrical Machines. Brugges, Belgium, August 25-28, 2002. This paper presents a lumped-parameter thermal model for a multi-barrier interior PM synchronous machine. The model consists of a network of 12 thermal resistances that make it possible to estimate temperatures at 9 critical points inside the machine including the stator end windings, rotor magnets, and the bearings. The details of the model arepresented and two machines are analyzed, including a 6 kW 12-pole automotive starter/alternator and a 0.5 kW 4-pole electric water pump machine. The lumped-parameter model results for both machines demonstrate good agreement with results obtained using detailed thermal finite element analysis. A. El-Refaie, N. Harris, T. Jahns, K. Rahman
2002-017 017 Using On-Line Parameter Estimation to Improve Efficiency of IPM Machine Drives IEEE PESC Conference, Queensland, Australia. June 23-27, 2002.** This paper presents a means to improve the efficiency of interior permanent magnet (IPM) synchronous machine drives which can be best implemented via continuous on-line self tuning. With this technique an improved maximum torque-per-ampere trajectory for IPM machine can be implemented including the effect of magnetic saturation. This improved trajectory can be shown to improve efficiency. The model-based estimation algorithm is based on commanded voltage and measured current and rotor position/velocity. The model has two equations where crosscoupled parameters can be eliminated for the robustness of parameter estimation. Parameter estimation is improved by combining the model with a closed loop observer. This algorithm is suitable for on-line estimation. The performance of this algorithm is illustrated by experimentation. The vector controller using this algorithm controls motor torque accurately under any load and speed. H. Kim, J. Hartwig, R.D. Lorenz
2002-018 018 A Control Method in dq Synchronous Frame for PWM Boost Rectifier under Generalized Unbalanced Operating Conditions. IEEE PESC Conference, Queensland, Australia. June 23-27, 2002.** This paper proposes a new control scheme for regulating the instantaneous power for pwm boost type rectifiers under generalized unbalanced operating conditions. By nullifying the oscillating components of instantaneous power at the poles of the converter instead of the front-end through solving a set of nonlinear control equations in real time, the harmonics in the output dc voltage can be eliminated more effectively under generalized unbalanced operating conditions in the ac input side. The control scheme allows the pwm rectifier to generate a dc output without substantial even-order harmonics and to maintain nearly unity power factor under generalized unbalanced operating conditions, which makes it possible to reduce the size of the dc-link capacitor and ac inductors leading to reduced total cost. Simulation results along with experimental results for the open-loop control using a laboratory prototype converter confirm the feasibility of the new control method. Y. Suh, V. Tijeras, T.A. Lipo
2002-019 019 Observers and State Filters in Drives and Power Electronics IEEE IAS OPTIM 2002, Brasov, Romania, May 16-18, 2002. Observers, state filters, dynamic stiffness, estimation accuracy, estimation bandwidth Sensors are often very costly elements of control systems in drives and power electronics. Furthermore the desired feedback signals can often only be obtained by substantially compromising the system integrity and reliability. This situation has promoted an increase in the use of observers and state filters as “sensor replacements” to estimate states and disturbances. The design of observers and the evaluation of their performance have not yet become standardized methodologies. This paper attempts to unify the key concepts in observer design and performance evaluation. The paper uses examples that are currently found in either commercial or research drive and power electronic systems. R.D. Lorenz
2002-020 020 A Three-Level MOSFET Inverter for Low Power Drive Submitted to IECON 2003 in Sevilla, Spain, Nov. 5-8, 2002.** This paper proposes operating a three-level Neutral Point Clamped (NPC) inverter using a two-level PWM method. This allows for the clamping diodes to be rated at a fraction of the main switches due to their low average current requirement. The use of a charge pump as a low cost method to obtain the isolated gate drive power supplies is extended for use with the NPC topology. Using this control method and circuits, an inverter based on high volume, low-cost low-voltage power MOSFETs is experimentally demonstrated as a possible economic alternative to an IGBT based drive for 120 Vrmssupplied systems. B. Welchko, M. Correa, T.A. Lipo
2002-021 021 Induction Machine Based Flywheel Energy Storage (FES) System Fed from a 20 kHz AC Link IEEE Trans. on Aerospace and Electronic Systems. This study introduces a field oriented controlled (FOC) induction machine based flywheel energy storage (FES) system fed from a 20kHz ac link and Pulse Density Modulated (PDM) Converter. The feasibilty of FES system is investigated both in software and hardware and is demonstrated succesfully in both cases. The investigated system offers a good potential as a temporary energy storage system for various applications from automobile industry to aerospace applications. I. Alan, T.A. Lipo
2002-022 022 Voltage Clamped Pulse Width Modulation of Matrix Converters. Department of Electrical and Computer Engineering University of Wisconsin-Madison, 2002. Matrix converters, PWM control, unity power factor, commutation. It is well known that the matrix converter offers high quality AC/AC conversion without need for large energy storage components. However, complicated PWM control techniques and potential commutation problems keep it from being widely used in industry. This paper proposes a novel matrix PWM control strategy based on DC/AC inverter theory, which not only generates only high order switching harmonics in both side and presents a unity power factor to the supply, but also posseses safe voltage commutation without need for perfect synchronization of the input voltage. L. Wei, T.A. Lipo
2002-023 023 A Direct Approach to Electrical Machine Performance Evaluation: Torque Density Assessment and Sizing Optimization ICEM 2002. Electrical machine design should be approached as a system optimization, more than a simple machine sizing when the machines are fed by a power converter. A great variety of electrical machines are available to accomplish this goal, and the task of comparing different options can be very difficult. A general sizing equation would be a very attractive tool which can easily be applied to every radial flux machines (RFM), axial flux machines (AFM) and transverse fluxmachines (TFM) and which takes different waveforms and machine characteristics into account. In this paper, a general approach is presented to summarize and interpret such an equation for radial, axial and transverse motors. Radial flux surface mounted PM machine and non-slotted TORUS surface mounted PM machine are used as sample applications. Optimum machine design for high power/torque density, high efficiency are achieved and illustrated in the paper for the non-slotted TORUS machines. Furthermore, the sizing equations are developed to compare six different 200 HP 6 pole 1200 rpm radial and axial flux machines in terms of torque/power densities, efficiencies, utilization, heat dissipation and weight. S. Huang, M. Aydin, T.A. Lipo
2002-024 024 Battery Energy Storage for Stand-Alone Micro-Source Distributed Generation Systems 6th IASTED Intl. Conf. On Power and Energy Systems, Marina Del Rey, May 13-15, 2002. Electrical machine design should be approached as a system optimization, more than a simple machine sizing when the machines are fed by a power converter. A great variety of electrical machines are available to accomplish this goal, and the task of comparing different options can be very difficult. A general sizing equation would be a very attractive tool which can easily be applied to every radial flux machines (RFM), axial flux machines (AFM) and transverse flux machines (TFM) and which takes different waveforms and machine characteristics into account. In this paper, a general approach is presented to summarize and interpret such an equation for radial, axial and transverse motors. Radial flux surface mounted PM machine and non-slotted TORUS surface mounted PM machine are used as sample applications. Optimum machine design for high power/torque density, high efficiency are achieved and illustrated in the paper for the non-slotted TORUS machines. Furthermore, the sizing equations are developed to compare six different 200 HP 6 pole 1200 rpm radial and axial flux machines in terms of torque/power densities, efficiencies, utilization, heat dissipation and weight. M. Illindala, G. Venkataramanan
2002-025 025 Control of Distributed Generation Systems to Mitigate Load and Line Imbalances Power Electronics Specialists Conference, Cairns, Australia, June 23-27, 2002. Modern distributed generation systems consist of various types of electrical energy sources such as photovoltaics, wind turbines and gas-fired micro-turbines providing utility grade ac power using a three-phase inverter interface. Although they are currently used as utility alternatives for energy sources, they are capable of maintaining conformance of voltage to stringent power quality standards such as the ITI/CBEMA (Information Technology Industry/Computer & Business Equipment Manufacturersí Association) curves, and hence are of additional value to customers. This paper investigates control of distributed generation systems to mitigate imbalances due to load conditions and voltage sags from system faults. It presents a unified controller that regulates the terminal voltage of sensitive loads under island mode and power flow in the grid-connected mode. M. Illindala, G. Venkataramanan
2002-026 026 Microgrids and Sensitive Loads IEEE Power Engineering Society Winter Meeting, New York, Jan 27-31, 2002. This paper discusses the issues related to the operation of a microgrid being called to feed reliable electric power to sensitive electrical loads. Challenges and solutions involved in terms maintaining adequate voltage quality and load tracking capabilities are discussed in the paper. M. Illindala, G. Venkataramanan
2002-027 027 Novel Encoder for SRM Drive with High Resolution Angle Control ISIE 2001, Pusan, Korea. S.J. Park, J-W Ahn, M.H. Lee, T.A. Lipo
2002-028 028 Design of an Integrated Motor/Controller Drive for an Automotive Water Pump Application IEEE IAS, Pittsburgh, PA October 13-17, 2002. This paper addresses key technical issues in the design of an integrated motor/controller drive unit for which the electric motor, its electronic controller, and load (a pump impeller) are all combined into a single structural assembly. A cost-based trade-off study is described that includes five different types of brushless machines, leading to the selection of an interior PM synchronous machine as the preferred prime mover for this application. The physical configurations of the motor and the controller were designed in order to minimize weight and volume while maximizing their cooling effectiveness. Several key issues associated with the controller design are described, including the physical layout of key components, the development of the EMI filter to meet automotive specifications, and analysis of worst-case component temperature rises using finite-element thermal analysis. N. Harris, T.M. Jahns, S. Huang,
2002-029 029 Design and Experimental Verification of a Direct-Drive Interior PM Synchronous Machine using a Saturable Lumped-Parameter Model IEEE IAS, Pittsburgh, PA, October 13-17, 2002. alternator; generator; interior permanent magnet synchronous machine; lumped parameter model; magnetic saturation; starter. This paper presents the design and experimental verification of a 6kW interior permanent magnet (IPM) synchronous machine intended for an automotive direct-drive starter/alternator application. The machine was designed using a saturable lumped-parameter magnetic circuit model in combination with a Monte Carlo optimization process that minimized the machine-plus-converter cost. An experimental IPM machine has been constructed based on the resulting design specifications. Laboratory tests have confirmed the accuracy of the analytical models for predicting the q-axis inductance Lq (including saturation effects) and the torque production characteristics, but discrepancies between the predicted and measured d-axis inductance Ld were revealed. The impact of these differences on machine performance is discussed, as well as potential adjustments in the IPM analytical model to improve the performance of future machines. E.C. Lovelace, T. Keim, J.H. Lang, D.D. Wentzloff, T.M. Jahns, J. Wai, P.J. McCleer, F Leonardi, J.M. Miller
2002-030 030 Engine Torque Ripple Cancellation with an Integrated Starter Alternator in a Hybrid Electric Vehicle, Implementation and Control In Proc. of IEEE IAS Annual Meeting, Pittsburgh, Oct 11-19, 2002. Observer, integrated starter alternator, engine torque, engine model, torque cancellation, active flywheel, hybrid vehicle. Integrated starter alternators (SA) allow greater electrical generation capacity and the fuel economy and emissions benefits of hybrid electric automotive propulsion. The drive usually comprises a field-oriented induction motor or vector-controlled permanent magnet motor coupled to the crankshaft of the engine directly or by a belt. These drives have high bandwidth torque control and may be used for active cancellation of the significant ripple torque inherent to internal combustion engines. This paper presents an analytical model useful for the analysis of the combustion engine torque and describes a control system that uses observer-based high fidelity torque feedforward and engine speed feedback to generate a disturbance input decoupling torque command for the SA to cancel the engine torque ripple. R.I. Davis, R.D. Lorenz
2002-031 031 Improved Current Regulators for IPM Machine Drives using On-Line Parameter Estimatio In Proc. of IEEE IAS Annual Meeting, Pittsburgh, Oct. 11-19, 2002. Current regulators for interior permanent magnet machines have unique challenges if high performance torque regulation is to be achieved. This paper presents a novel approach for fully decoupling the problematic cross-coupling with estimated parameters from on-line self-tuning. In the online estimation algorithm, the model is formulated such that cross-coupled estimated parameters are eliminated, which improves the parameter estimation robustness. Parameter estimation is further improved by combining the model with a closed loop observer. Cross-coupling terms can then be decoupled using estimated parameters to improve the performance of the current regulator. H. Kim, R.D. Lorenz
2002-032 032 Sensorless Control of Interior Permanent Magnet Machine Drives with Zero-Phase-Lag Position Elimination In Proc. of IEEE IAS Annual Meeting, Pittsburgh, PA, Oct 11-19, 2002. sensorless control, observer-based control, state filter estimation, interior pm machine drive This paper presents an improved method to estimate rotor motion states for an interior permanent magnet machine drive. This approach is based on the estimation of the saliency-based EMF in a stationary reference frame using a state filter. The spatial information obtained from the estimated saliency-based EMF is used in an observer to estimate the motor motion states. By adding the commanded torque as a feedforward input to the observer, the motion state estimation has zero phase-lag, providing a very high bandwidth estimate. H. Kim, M.C. Harke, R.D. Lorenz
2002-033 033 A Low-Cost Inverter for Domestic Fuel Cell Applications Power Electronics Specialists Conference, Cairns, Australia, June 23-27, 2002. Fuel cell, Renewable Energy, Distributed Generation. The utilization of fuel cells for distributed power generation requires the development of an inexpensive inverter that converts a fuel cell’s variable dc output into useful ac. To encourage this development the US Department of Energy and the IEEE setup and sponsored a national US student competition with a substantial first prize going to the lowest cost working fuel cell inverter: the 2001 Future Energy Challenge (FEC). This paper describes the work of the University of Wisconsin FEC Team. It discusses the topology used to achieve the said objective, the rationale used in choosing this topology, detailed component selection optimized to minimize cost, and the dc/dc and dc/ac converter control. Finally some conclusions are made and a new total-systemapproach design using a high voltage fuel cell is proposed to further reduce the cost of the inverter. A. Tuckey, J. Krase
2002-034 034 A New Axial Flux Surface Mounted Permanent Magnet Machine Capable of Field Control In Proc. of IEEE IAS Annual Meeting, Pittsburgh, PA, Oct 11-19,2002. Axial flux machines, surface mounted PM machines, TORUS, field control, field weakening, finite element analysis. This paper presents a new axial flux surface mounted permanent magnet (PM) field controlled TORUS type (FCT) machine. Machine structure and principles are explored and the field weakening feature of the topology as well as the advantages of the machine are presented in the first part. The second section introduces the linear model and sizing analysis using generalized sizing equations. Optimization of the machine pole number and power density maximization for the optimum pole number is also achieved. In the third section, 3D Finite Element Analyses (FEA) of the topology are illustrated for different field currents in order to accomplish the machine design and to determine the sizing of the optimum field winding. Furthermore, torque analysis of the FCT machine using 3D finite element analysis is also carried out and illustrated in the paper. M. Aydin, S. Huang, T.A. Lipo
2002-035 035 Reduction of DC Bus Capacitor Ripple Current with PAM/PWM Converter IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 40, NO. 2, MARCH/APRIL 2004 Industrial drives; Current ripple; Electrolytic capacitor modeling; Buck Rectifier; PAM; PWM; Current Source Rectifiers; Voltage Source Inverter; ASD; ESR. Electrolytic Capacitors are used in nearly all adjustable speed drives (ASD) and they are one of the components most prone to failure. The main failure mechanisms include the loss of electrolyte through outgassing and chemical changes to the oxide layer. All the degradation mechanisms are exacerbated by ripple current heating. Since the equivalent series resistance (ESR) of electrolytic capacitors is a very strong function of frequency it must be properly modeled to accurately calculate the power loss. In this paper a method to reduce the ripple current in a constant Volts/Hertz (V/f) Pulse Amplitude Modulation (PAM/PWM) converter driving an induction motor is investigated. The DC bus voltage amplitude is reduced in proportion to speed by a buck or current source rectifier (CSR) and the PWM modulation index is increased to achieve a reduced ripple current below base speed. It is shown that this mode of operation can lead to a significant reduction in capacitor power loss leading to increased capacitor lifetime or decreased capacitor size. The capacitor heating is analyzed using numerical and analytical techniques. Experimental results are provided to verify the analytical results. F.D. Kieferndorf, M. Foerster, T.A. Lipo
2002-036 036 An Integrated Approach to Power Electronics Systems Proceedings of the power conversion conference. PCC Osaka 2002, vol 1. April 2002. Power integrated circuits; packaging; power semiconductor devices; sensors; and simulation. Today’s power electronics systems are typically manufactured using non-standard parts, resulting in labor-intensive manufacturing processes, increased cost and poor reliability. As a possible way to overcome these problems, this paper discusses an integrated approach to design and manufacture power electronics systems to improve performance, reliability and cost effectiveness. Addressed in the paper are the technologies being developed for integration of both power supplies and motor drives. These technologies include the planar metalization to eliminate bonding wires, the integration of power passives, the integration of current sensors, the development of power devices to facilitate integration as well as to improve performance, and the integration of necessary CAD tools to address the multidisciplinary aspects of integrated systems. The development of Integrated Power Electronics Modules (IPEMs) is demonstrated for two applications: (1) 1kW asymmetrical half-bridge DC/DC converter and (2) 1-3kW motor drive for heating, ventilation and air conditioning (HVAC). Electrical and thermal design tradeoffs of IPEMs and related enabling technologies are described throughout the paper. F.C. Lee, J.D. Van Dyke, D. Boroyevich, T.M. Jahns, R.D. Lorenz, T.P. Chow, R.J. Gutmann, P. Barbosa
2002-037 037 Reciprocity-Transposition-Based Sinusoidal Pulsewidth Modulation for Diode-Clamped Multilevel Converters, IEEE Transactions on Industrial Electronics, Vol. 49, No. 5, October 2002. Multilevel systems, power conversion, pulsewidth modulation. Modulation strategies for multilevel inverters have typically focused on synthesizing a desired set of three phase sinusoidal voltage waveforms using a fixed number of dc voltage levels. This results in the average current injection and hence the net power drawn from the multiple dc bus terminals to be unmatched and time varying. Subsequently, the dc-bus voltages are unregulated, requiring corrective control action to incorporated. In this paper, the principle of reciprocity transposition in introduced as a means for modeling the dc-bus current injection simultaneously as the modulation strategy is formulated. Furthermore, a new sinusoidal pulsewidth-modulation strategy that features constant and controllable current injection at the dc-bus terminals while maintaining output voltage waveform quality is introduced. The proposed strategy is general enough to be applied to converters with an even number of levels and an odd number of levels. Analytical results comparing the performance of the proposed modulator with a conventional multiple carrier modulator are presented for example multilevel converters with four and five levels. Computer simulation results verifying the analytical results are presented for a four-level converter. G. Venkataramanan, A. Bendre
2002-038 038 A Nonlinear Control of the Instantaneous Power in dq Synchronous Frame for PWM AC/DC Converter under Generalized Unbalanced Operating Conditions In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18,2002. pp.1189-1196 PWM ac/dc converter, generalized unbalanced operating conditions, instantaneous power, nonlinear control This paper proposes a new control scheme for regulating the instantaneous power for pwm ac/dc type rectifiers under generalized unbalanced operating conditions. By nullifying the oscillating components of instantaneous power at the poles of the converter instead of the front-end through solving a set of nonlinear control equations in real time, the harmonics in the output dc voltage can be eliminated more effectively under generalized unbalanced operating conditions on the ac input side. The control scheme allows the pwm rectifier to generate a dc output without substantial even-order harmonics and to maintain nearly unity power factor under generalized unbalanced operating conditions, which makes it possible to reduce the size of the dc-link capacitor and ac inductors leading to the possibility of reduced total cost. Simulation results along with experimental results under the two examples of the unbalanced operating conditions confirm the feasibility of the new control method. Y. Suh, V. Tijeras, T.A. Lipo
2002-039 039 Dual-Rotor, Radial-Flux, Toroidally-Wound, Permanent-Magnet Machines In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18,2002. RFTPM Machines, PM Machine Design, Toroidal Windings, Cogging Torque, and Electrical Machine Optimization A novel machine family – dual-rotor, Radial-Flux, Toroidally-wound, Permanent-Magnet (RFTPM) machines – is proposed in order to substantially improve machine torque density and efficiency. After the principles of operation, configurations, and features are discussed, the machine design and optimization guidelines are given. A prototype has been designed, built, and tested. The measured torque density of the prototype, which well matches the design value, is almost three times of that of the induction machine with the same power and speed. Meanwhile the efficiency is still kept high and the material cost is kept low by using ferrite magnets. Three novel approaches are proposed to reduce the cogging torque in RFTPM machines, whose validity is verified by FEA results and experimental measurements. R. Qu, T.A. Lipo
2002-040 040 Analysis and Modeling of Airgap & Zigzag Leakage Fluxes in a Surface-Mounted-PM Machine In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18,2002. Airgap leakage flux, zigzag leakage flux, PM machine, PM machine design In this paper the magnetic characteristics of surface-mounted permanent magnet machines are analyzed and modeled. The airgap and zigzag leakage fluxes are analytically expressed in terms of the magnetic material properties and the motor dimensions. Both factors are essential quantities for the accurate prediction of the flux distribution within the machine and of the machine torque. Therefore, they are desired for the purpose of machine design and optimization. In order to evaluate the validity of the proposed models, the Finite Element Method (FEM) analysis is used. The results show that the errors between the FEM results and analytical predictions are less than 1% for both the airgap and zigzag leakage fluxes. This accuracy is also proven by the prototype measurements R. Qu, T.A. Lipo
2002-041 041 A Critical Evaluation of High Power Hard and Soft Switched Isolated DC-DC Converters In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18, 2002. switching losses, dc/dc converters, soft switching Realization of high power isolated dc-dc converters is largely dependent on managing converter parasitics and losses. In this paper, four different dc/dc converter topologies are compared in terms of their losses. The topologies include hard switched half bridge, switched snubber half bridge, zero voltage switching phase shifted full bridge and loss limited (semi soft switched) full bridge converters. These topologies have been designed to obtain 350 V 300 A dc output from a 650 V dc input at 20 kHz switching frequency. Design results and loss evaluations are presented. M.T. Aydemir, A. Bendre, G. VEnkataramanan
2002-042 042 A Design Procedure for a PM Machine with Extended Field Weakening Capability In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18, 2002. A design procedure for the Consequent Pole Pemanent Magnet (CPPM) machine is presented. Due its double excitation nature (PM and field winding) and inherent threedimensional flux distribution an apropriate set of equations must be derived to model its magnetic structure. For practical operating conditions, radial, axial and tangential flux component are present. Therefore a convenient representation of the magnetic sources and their magnetic paths are necessary. For this purpose, a simplified reluctance-based equivalent circuit for 2-poles is developed to capture the main features of the machine. Approximated expressions for the airgap flux and the airgap flux density are derived. In these expressions the constant contribution of the PM and the variable flux provided by the field winding are taken into account. In addition, a formulation to calculate AC and DC slot geometry, copper and iron losses estimation and output power are developed. Finally, an optimization procedure is outlined based on maximum material utilization under current and magnetic loading constraints. J.A. Tapia, F. Leonardi, T.A. Lipo
2002-043 043 Reduced Common Mode Carrier-Based Modulation Strategies for Cascaded Multilevel Inverters In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18, 2002. This paper presents carrier-based modulation strategies for cascaded multilevel inverters that substantially eliminate common mode voltage on the output phases. The paper begins by developing generic multilevel inverter reference waveforms that use only “allowed” space vectors to achieve reduced common mode voltage. A graphical technique is then proposed that allows various carrier disposition modulation strategies for a diode clamped inverter to be converted to equivalent modulation of a cascaded inverter for any fundamental reference waveform. This graphical technique is confirmed for both APOD and PD equivalent modulation of a cascaded inverter, and is then used to create reduced common mode modulation strategies for cascaded inverters from their equivalent counterparts for diode-clamped inverters under both continuous and discontinuous switching conditions. The strategies have been confirmed by both simulation and experimental results obtained using a cascaded five-level inverter. P.C. Loh, D.G. Holmes, Y. Fukuta, T.A. Lipo
2002-044 044 DC Bus Ripple Minimization in Cascaded H-Bridge Multilevel Converters under Staircase Modulation In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18, 2002. H bridge multilevel converter, power balancing, conduction angle, harmonic reduction, capacitor sizing Cascade connected H bridge multilevel converters are becoming an attractive topology for very high power applications. Due the single phase loading of the individual bridges, the dc link capacitors required in these converters are faced with a heavy stress. The problem is particularly acute with stair-case type of modulation strategies. This paper presents an approach for equalizing the power drawn from each H bridge within less than one cycle period with the aim of reducing capacitor sizing. The presented approach is based on rearranging the switching strategies with focusing on the redundancies in synthesizing output voltage of H bridge multilevel converters. The proposed approach also holds nearly the same degree of freedom in selecting conduction angles and attains similar levels of harmonic performance as with conventional switching angle selection approaches. The analysis presented in this paper is also confirmed by simulation. Y. Fukuta, G. Venkataramanan
2002-045 045 A Time-Based Double Band Hysteresis Current Regulation Strategy for Single-Phase Multilevel Inverters In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18, 2002. Most multilevel inverter hysteresis current regulators use either multiple hysteresis bands, or a time-based switching logic that forces the current error back to zero by recursively stepping through successive voltage levels. Of these two alternatives, the time-based approach has the merit of only requiring simple analog circuitry and digital logic to implement the voltage level selection process for inverters of any number of voltage levels. But the approach can be less stable and have a poorer dynamic response than a multiple hysteresis band system. This paper presents a double band regulator that uses the slope of the current error to help determine the appropriate steady state voltage level to keep this error within the inner hysteresis band, while still allowing switching to the extreme inverter states during transient conditions to reduce the current error as rapidly as possible. The regulator achieves better stability and dynamic performance than previously reported schemes. The paper also presents an adaptation of the system to control a hybrid seven-level inverter. Theory, simulation and experimental results are presented. P.C. Loh, G.H. Bode, D.G. Holmes, T.A. Lipo
2002-046 046 Modularization and Integration As a Future Approach to Power Electronics Systems In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18, 2002. Today’s power electronics systems are typically manufactured using non-standard parts, resulting in laborintensive manufacturing processes, increased cost and poor reliability. As a possible way to overcome these problems, this paper discusses an integrated approach to design and manufacture power electronics systems that intends to improve performance, reliability and cost effectiveness. Addressed in the paper are the technologies being developed for integration, including the planar metalization to eliminate wire bonding, the integration of power passives, and the integration of necessary CAD tools to address the multidisciplinary aspects of integrated systems. The development of Integrated Power Electronics Modules (IPEMs) is demonstrated for an application using the 1kW asymetrical half-bridge DC/DC converter. The electrical and thermal design tradeoffs for the active IPEM, and the design optimization results of the passive IPEM are described throughout the paper as well. F.C. Lee, J.D. Van Wyk, D. Boroyevich, T.M. Jahns, T.P. Chow, P. Barbosa
2002-047 047 Investigation of Parallel Operation of IGBTs In Proc. of IEEE 37th IAS Annual Meeting, Pittsburgh, PA, Oct 13-18, 2002. ** parallel operation; IGBT; discrete devices; module devices; switching effects; standarized converters Widespread application of IGBTs in the past decade has resulted in dramatic improvement in performance of power electronic converters, with simultaneous reduction in costs. In order to further reduce the cost of power electronics systems and improve their reliability it is imperative that techniques for standardized and integrated architectures be adopted, allowing them to be mass-customized for a larger class of applications. One of the key factors that allow broad application of a power switching devices rated at a lower power level across large power levels is ease of parallel operation. This paper is devoted to presenting the results from investigation of parallel operation of IGBT devices. Experimental and computer simulation results are presented. J.J. Nelson, G. Venkataramanan, B.C. Beihoff
2002-048 048 An Integrated Approach to Power Electronics Systems In Proc. of EPE Power Electronics and Motion Control Conf., Dubrovnik, Croatia, Sept. 2-4, 2002. Power integrated circuits; packaging; power semiconductor devices; sensors; and simulation. Today’s power electronics systems are typically manufactured using non-standard parts, resulting in labor-intensive manufacturing processes, increased cost and poor reliability. As a possible way to overcome these problems, this paper discusses an integrated approach to design and manufacture power electronics systems to improve performance, reliability and cost effectiveness. Addressed in the paper are the technologies being developed for integration of both power supplies and motor drives. These technologies include the planar metalization to eliminate bonding wires, the integration of power passives, the integration of current sensors, the development of power devices to facilitate integration as well as to improve performance, and the integration of necessary CAD tools to address the multidisciplinary aspects of integrated systems. The development of Integrated Power Electronics Modules (IPEMs) is demonstrated for two applications: (1) 1kW asymmetrical half-bridge DC/DC converter and (2) 1-3kW motor drive for heating, ventilation and air conditioning (HVAC). Electrical and thermal design tradeoffs of IPEMs and related enabling technologies are described in the paper. F.C. Lee, J.D. Van Wyke, D. Boroyevich, T.M. Jahns, R.D. Lorenz, T.P. Chow, R.J. Gutmann, P. Barabosa
2002-049 049 A Saturating Lumped-Parameter Model for an Interior PM Synchronous Machine IEEE Transactions on Industry Applications, Vol. 38, Issue. 3, May/June 2002. Generator, interior permanent-magnet synchronous machine, lumped-parameter model, magnetic circuit analysis, magnetic saturation, optimization, starter. This paper presents a lumped-parameter magnetic model for an interior permanent-magnet synchronous machine. The model accounts for the effects of saturation through a nonlinear reluctance-element network used to estimate the -axis inductance. The magnetic model is used to calculate inductance and torque in the presence of saturation. Furthermore, these calculations are compared to those from finite-element analysis with good agreement. E.C. Lovelace, T.M. Jahns, J.H. Lang
2002-050 050 Current Reconstruction using Integrated Current Sensor in Three-Phase Motor Drives Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 2002. Integrated current sensors that are directly incorporated into the design of MOS-gated power devices create opportunities for reduced sensor size and cost in future motor drives. However, they also present special challenges due to the incomplete phase current feedback information they provide. This paper identifies alternative integrated current sensor configurations intended for three-phase motor drives and investigates observer techniques for reconstructing the phase current waveforms using the available sensor feedback information. Analytical results indicate that the observers can perform the desired reconstruction very well even in the presence of significant model parameter errors provided that the bandwidth of the observer is sufficiently high. H-R Kim, T.M. Jahns
2002-051 051 Investigation of Parallel Operation of IGBTs 37th IAS Annual Meeting. Conference Record of the Industry Applications Conference,(Volume:4 ), 2002 parallel operation; IGBT; discrete devices; module devices; switching effects; standarized converters Widespread application of IGBTs in the past decade has resulted in dramatic improvement in performance of power electronic converters, with simultaneous reduction in costs. In order to further reduce the cost of power electronics systems and improve their reliability it is imperative that techniques for standardized and integrated architectures be adopted, allowing them to be mass-customized for a larger class of applications. One of the key factors that allow broad application of a power switching devices rated at a lower power level across large power levels is ease of parallel operation. This paper is devoted to presenting the results from investigation of parallel operation of IGBT devices. Experimental and computer simulation results are presented. J.J. Nelson, G. Venkataramanan, B.C. Beihoff
2002-052 052 Double-Sided IPEM Cooling using Miniature Heat Pipes IEEE Transactions on Components and Packaging Technologies (Volume:28 , Issue: 4 ). IPEM planar interconnect technologies offer opportunities for improved thermal management by allowing thermal access to the upper side of the power devices. This paper investigates the feasibility of using miniature heat pipes to achieve effective double-sided cooling by analyzing the complete thermal circuit associated with the power device. A nominal case was modeled with ANSYS ™ finite element software in a single-sided and double-sided configuration. The double-sided configuration results in a 12°C reduction in the maximum temperature compared to the single-sided case. This corresponds to a 15% decrease in the maximum temperature rise relative to ambient or a similar increase in allowable power generation. Twenty-eight percent of the heat was removed from the upper side of the IPEM in the double-sided case. This paper describes the numerical model, presents some results, and discusses the potential for future research relative to IPEM cooling and miniature heat pipes. T. Martens, G.F. Nellis, T.M. Jahns, J.M. Pfotenhauer
2002-053 053 Experimental Evaluation of a Two-phase Axial Flux Circumferential Current (AFCC) Permanent Magnet Machine Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 2002. Transversal flux motors, Permanent magnet motors, Drives, and Design After a summary of the single-phase Axial Flux Circumferential Current (AFCC) machine, a two-phase AFCC machine is presented to reduce the high pulsation torque of a previous single-phase topology. A prototype of the two-phase AFCC machine is discussed. The experimental analyses of the prototype are presented. The results show that coupling of two phases is a valid method to reduce the large pulsation torque related to the single-phase topology, while the torque capability is still kept high. Powdered iron material is employed in the prototype to accommodate the three-dimensional flux distribution in the stator and rotor. The iron losses of the material are reported. R. Qu, J. Luo, S. Huang, T.A. Lipo
2003-001 001 A Self-Boost Charge Pump Topology for a Gate Drive High-Side Power Supply APEC 2003 Conference, Miami Beach, FL, Feb. 9-13, 2003, pp 126-131. ** high-side gate drive, transformerless, floating, bootstrap power supply, IPEM A self-boost charge pump topology is presented for a floating high-side gate drive power supply that features high voltage and current capabilities for use in Integrated Power Electronic Modules (IPEMs). The transformerless topology uses a small capacitor to transfer energy to the high-side switch from a single power supply referred to the negative rail. Unlike conventional bootstrap power supplies, no switching of the main phase-leg switches is required to provide power continuously to the high-side gate drive, even if the high-side switch is permanently on. Additional advantages include a low parts count and simple control requirements. A piecewise linear model of the self-boost charge pump is derived and the circuit’s operating characteristics are analyzed. Simulation and experimental results are provided to verify the desired operation of the new charge pump circuit. S. Park, T.M. Jahns
2003-002 002 Fast Thermal Profiling of Power Semiconductor Devices Using Fourier Techniques APEC 2003 Conference, Miami Beach, FL, Feb. 9-13, 2003, pp. 1023-1028.** thermal analysis; fourier techniques; power semiconductor device reliability Accurate prediction of temperature variation of power semiconductor devices in power electronic circuits is important to obtain optimum designs and estimate reliability levels. Temperature estimation of power electronic devices has generally been performed using transient thermal equivalent circuits. In the presence of varying load cycles, it has been typical to resort to a time domain electrical simulation tool such as PSpiceTM or SABERTM to obtain a time series of the temperature profiles. However, for complex and periodic load cycles, time series simulation is time consuming. In this paper, a fast Fourier analysis based approach is presented for obtaining temperature profiles for power semiconductors. The model can be implemented readily into a spreadsheet or simple mathematical algebraic calculation software. The technique can be used for predicting lifetime and reliability level of power circuits easily. Details of the analytical approach and illustrative examples are presented in the paper. J.J. Nelson, G. Venkataramanan, A.M. El-Refaie
2003-003 003 Integrating Giant Magnetoresistive Current and Thermal Sensors in Power Electronic Modules Proc. of APEC 2003 Conference, Miami Beach, FL, Feb. 9-13, 2003, pp. 773-777.** E.R. Olson, R.D. Lorenz
2003-004 004 A Reduced Common Mode Hysteresis Current Regulation Strategy for Multilevel Inverters APEC 2003 Conference, Miami Beach, FL, Feb. 9-13, 2003, vol.1, pp 576 - 582, IEEE IAS Annual Meeting, 2002, IEEE Transactions on Power Electronics, vol. 19, iss. 1, Jan. 2004, pp. 192-200. Multilevel inverters, hysteresis, current regulation, common mode voltages. This paper presents a new hysteresis current regulation technique with reduced common mode switching for three-phase multilevel inverters. The proposed technique uses three independent multilevel hysteresis current regulators to generate three sets of complementary gating signals through the comparison of the measured current errors with implemented hysteresis limits. These gating signals are then distributed to each complementary switch pair of the multilevel inverter structure to switch with reduced common mode voltage. Additionally, by intelligently compensating for transition delays during dead-times, common mode voltage can essentially be eliminated completely. Two versions of the common mode regulation technique are derived by using either the line currents or differences between the line currents, known as delta currents, as the control variables. A detailed investigation is presented to determine that the delta currents are the optimal control variables. The performance of the proposed strategy is confirmed through both simulation and experimental investigations. P.C. Loh, D.G. Holmes, Y. Fukuta, T.A. Lipo
2003-005 005 Development of Static Switchgear for Utility Interconnection in a Microgrid Power and Energy Systems PES 2003, Palm Springs, CA, Feb.24-26, 2003, pp. 235-240. Distributed generation, Static switch, Synchronization control. Conventional power generation systems are increasingly being been seen to be disadvantageous due to high levels of environment pollution and relatively low power quality. This is particularly true for sensitive industrial processes that depend on high power quality indices to maintain uninterrupted operation. In many cases, the use of a distributed generation system along with a fast utility interconnection device can dramatically mitigate power quality problems in a cost-effective manner. A static switch that enables rapid disconnection from the utility grid in case of power quality problems and seamless reconnection when the problem disappears is vital for such a solution to be viable. This paper discusses the development of a static switch for utility interconnection of distributed generation systems in a microgrid. H. Zhang, M. Chandorkar, G. Venkataramanan
2003-006 006 A Comparative Evaluation of Motor Drive Topologies for Low-Voltage, High-Power EV/HEV Propulsion Systems IEEE International Symposium on Industrial Electronics, ISIE'03, Rio de Janeiro, Brazil, June 9-12, 2003. The recent adoption of the 42 V Powernet standard for the next generation of vehicles has focused substantial research effort into the design of electric machines for light hybrid vehicles. However, research investigating the merits of topology selection for this application has been sparse. This paper investigates the potential performance benefits, which could be realized by adopting a different inverter topology. This paper discusses the merits of deltaconnected motors, bipolar inverters and cascaded inverterswhen compared to a standard inverter. The flexibility provided by adopting a non-standard topology can produce a better overall design when one or more of the design specifications are proving difficult to meet economically with the standard topology. As a particular design example, this paper shows that a cascaded inverter topology driving an open winding motor can increase the high-speed power density of an induction motor by 73%. For an interior permanent magnet motor, this paper shows that this topology can increase low speed torque by 9% and high-speed power by up to 300%. B.A. Welchko, J.M. Nagashima
2003-007 007 Turbogenerator End Winding Leakage Inductance Calculation Using a 3-D Analytical Approach Based on the Solution of Neumann Integrals IEEE International Electric Machines and Drives Conference, Madison, WI, June 1-4, 2003, pp. 1576-1582. An analytical technique that can be effectively used for the calculation of the end winding leakage inductance of a turbogenerator has been presented. It is based on a 3-D geometric model of the end winding region in which each coil is modeled as a set of serially connected straight filaments. The calculation of the mutual inductance of the end coils is based on the multiple solutions of the Neumann integral. The method also accounts for the influence of stator core iron on the end winding leakage inductance by using the method of images. The results of the calculations have been compared with the measured values of the leakage inductance for 247 MVA turbogenerator manufactured by KON?AR Generators and motors Inc., Zagreb, Croatia. The principle of the end winding leakage inductance calculation described herein can be effectively used for other types of machines and windings as well. D. Ban, D. Zarko, I. Mandic
2003-008 008 Fault Tolerant Three-Phase AC Motor Drive Topologies; A Comparison of Features, Cost, and Limitations IEEE International Electric Machines and Drives Conference, Madison, WI, June 1-4, 2003, pp. 539-546, IEEE Transactions on Power Electronics, Volume: 19, Issue: 4, July 2004 Pages:1108 - 1116. Inverter faults, phase-leg short-circuits, silicon overrating cost factor (SOCF), single-phase open-circuits, three-phase inverter, three-phase ac motor drive topologies. This paper compares the many fault tolerant threephase ac motor drive topologies that have been proposed to provide output capacity for the inverter faults of switch short or open-circuits, phase-leg short-circuits, and single-phase open-circuits. Also included is a review of the respective control methods for fault tolerant inverters including two-phase and unipolar control methods. The output voltage and current space in terms of components is identified for each topology and fault. These quantities are then used to normalize the power capacity of each system during a fault to a standard inverter during normal operation. A silicon overrating cost factor is adopted as a metric to compare the relative switching device costs of the topologies compared to a standard three-phase inverter. B.A. Welchko, T.A. Lipo, T.M. Jahns, S.E. Schulz
2003-009 009 Dynamic Phenomena in Wind Farms with a Mix of Line Connected Induction Generators and Inverter Embedded Generators, Proc. of Carribbean Colloquium on Electric Power Quality, July, 2003. G. Venkataramanan, M. Illindala
2003-010 010 General Closed-form Analytical Expressions of Air-gap Inductances for Surface-mounted Permanent Magnet and Induction Machines IEEE International Electric Machines and Drives Conference, Madison, WI, June 1-4, 2003, pp. 443-448. General closed-form analytical expressions for airgap inductance of surface-mounted PM and induction machines are derived without the assumption of sinusoidally wound windings. The expressions are suitable for all single- or doublelayer, concentrated or distributed windings, and demonstrated to be identical with the winding function approach and share the same advantage that all the harmonics are inherently included. These expressions are straightforward analytical equations, which are easily used by machine designers. R. Qu, T.A. Lipo
2003-011 011 Sizing Equation Analysis for Field Controlled PM Machines: A Unified Approach IEEE International Electric Machines and Drives Conference, Madison, WI, June 1-4, 2003, pp. 1111-1116 In this paper, the sizing equation analyses are presented for two different radial and axial flux field controlled PM machines. These types of machines have two sources of excitation which allows one to easily control the airgap flux. Variable flux component provided by the field winding and fixed flux component obtained from PM converge into the airgap so that an additive or subtractive effect can be achieved over a wide range such that the machine speed range can be increased. A detailed analysis is made in order to evaluate the performance, power density and efficiency. In addition, guidelines for optimal design of the two machines are pointed out. J.A. Tapia, M. Aydin, S. Huang, T.A. Lipo
2003-012 012 Investigation of Dual-bridge Matrix Converter Operation under Unbalanced Source Voltages IEEE Power Electronics Specialists Conference (PESC) 2003, Acapulco, Mexico, June 15-19, 2003, pp. 1293-1298. The dual-bridge matrix converter concept has been gaining recognition as a promising circuit alternative in recent years. In this paper, a direct feed-forward unbalance control method with power factor adjustment ability is developed for a 9-switch dual-bridge matrix converter system. It firstly detects the line side source voltages. Then, after adjusting the switching functions of only the line side converter, the system can provide balanced output voltage with slightly distortion of line side current. Analysis demonstrates that the output voltage capacity and power factor adjustability is limited under unbalanced conditions. Theory analysis, simulation and experimental results are presented in the paper to verify the effectiveness of this control method. L. Wei, Y. Matsushita, T.A. Lipo
2003-013 013 Robust Voltage Commutation of Conventional Matrix Converter IEEE Power Electronics Specialists Conference (PESC), Acapulco, Mexico, June 15-19, 2003, pp.717-722. The three-phase ac-ac converter termed the matrix converter can provide high quality input/output waveforms and adjustable input power factor without any large energy storage component. However, it has not yet found much acceptance in industry. The main reason is that it requires a complicated commutation scheme to prevent input side short circuits and output side open circuits. This paper develops a new voltage commutation scheme for the conventional matrix converter. One advantage of this scheme is that it provides robust voltage commutations for the converter without sacrificing the quality of the line side current waveforms. The second advantage is that it needs the least information from the system than any algorithm yet reported. It only detects the line side synchronization angle which can have detection errors within –p/6 radians under unity input power factor to provide accurate commutation. The last advantage of this scheme is that it can provide easier shut down sequences for the system. Theoretical analysis, simulation and experimental results are provided to verify its effectiveness in the paper. L. Wei, T.A. Lipo, H. Chan
2003-014 014 Design of a Linear Bulk Superconductor Magnet Synchronous Motor for Electromagnetic Aircraft Launch Systems IEEE International Electric Machines and Drives Conference (IEMDC), Madison, WI, June 1-4, 2003, vol.1, pp.494-500, IEEE Transactions on Applied Superconductivity, Mar. 2004, vol.14, no. 1, pp. 54-62. Bulk superconductor, electromagnetic aircraft launch, linear motors. High-temperature superconducting (HTS) material in bulk form is used to design a linear synchronous motor for an electromagnetic aircraft launch system. The motor is designed without an iron core. Stator coils are placed in the air while the permanent magnets used in conventional design of linear permanent magnet synchronous motors are replaced by the HTS bulk magnets. The physical, operational, and equivalent circuit parameters of the linear motor with HTS bulk magnets are compared with those of a linear permanent magnet synchronous motor and linear induction motor designed for the same application. Results show that utilizing superconducting magnets is only superior at temperatures below 40 K. G. Stumberger, D. Zarko, M.T. Aydemir, T.A. Lipo
2003-015 015 Application of Bi-State Magnetic Material to an Automotive IPM Starter/Alternator Machine IEEE International Electric Machines and Drives Conference (IEMDC), Madison, WI, June 1-4, 2003, vol.3, pp.1379-1387. Permanent magnet machines, synchronous machines, magnetic materials, rotating machine mechanicalfactors A new bi-state soft magnetic material has been developed that can have its normally high magnetic permeability reduced permanently to that of air by means of heat treatment. As a result, localized heating via laser or other means can be used to locally “unmagnetize” regions in machine laminations while retaining the high permeability of adjacent untreated regions. A 6 kW interior permanent magnet (IPM) direct-drive starter/alternator machine was used as the target for this investigation. Two alternative designs for the same set of starter/alternator specifications are presented using the new magnetic material for the rotor laminations. Lumpedparameter magnetic circuit models including saturation were used to design both machines and the electromagnetic performance results were subsequently confirmed using finite element analysis (FEA). These results indicate that the performance specifications can be met using this new material while significantly increasing the mechanical integrity of the rotor at high speeds. Advantages and limitations of using this new bi-state magnetic material in IPM machine designs for starter/alternators and other applications are discussed. A.M. El-Refaie, T.M. Jahns
2003-016 016 Performance Evaluation of An Axial Flux Consequent Pole PM Motor Using Finite Element Analysis IEEE International Electric Machines and Drives Conference, Madison, WI, June 1-4, 2003, pp. 1682-1687. Performance evaluation of an axial flux surface mounted permanent magnet (PM) field controlled TORUS type (FCT) disc machine is presented in this paper. This new machine is an axial flux configuration with true field weakening capability since the flux is controlled by the DC field winding rather than opposing the magnets. Structure and operating principles are summarized in the first section. Next, 3D Finite Element Analysis (FEA) including no-load and on-load characteristics and back EMF variation for various armature currents and DC field current are explored. Furthermore, torque characteristics of the FCT machine for different field currents are explored. Minimization of cogging torque calculations and the effect of skewing the magnets are also examined. M. Aydin, S. Huang, T.A. Lipo
2003-017 017 Performance Comparison of Dual-Rotor Radial-Flux and Axial-Flux Permanent-Magnet BLDC Machines IEEE International Electric Machines and Drives Conference, Madison, WI, June 1-4, 2003, pp. 1948-1954. A novel machine family – dual-rotor, Radial-Flux, Permanent-Magnet (RFPM) machines -- has demonstrated that it can substantially improve machine torque density and efficiency. The objective of this paper is to provide a performance comparison between two major alternatives of this technology: Surface-mounted dual-rotor RFPM machines and Axial-Flux Permanent-Magnet (AFPM) machines. The comparison is accomplished at four power levels ranging from 3 to 50 HP at a constant speed of 1800 RPM. The comparison includes material weights and costs, copper and iron losses, torque and power per unit active volume, torque per unit active material weight, magnet material effect, losses per unit airgap area, and machine efficiency. Pole number effects on both machine types are investigated as well. The results reveal an indication of the machine best suited with respect to performance criterion for a particular design requirement. R. Qu, M. Aydin, T.A. Lipo
2003-018 018 Initial Rotor Position Estimation for an Integrated Starter Alternator IPM Synchronous Machine Proc. of European Power Electronics Conference, Toulouse, France, Sept. 2-4, 2003, paper no. 729. Sensorless control, Permanent magnet motors, Motion control, Automotive applications The authors gratefully acknowledge the financial support and motivation of the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC) of University of WisconsinMadison and the Center for Power Electronics Systems (CPES). H. Kim, K.K. Huh, M.C. Harke, J. Wai, R.D. Lorenz, T.M. Jahns
2003-019 019 Expert System for Integrated Control and Supervision of Dry-End Sections of Paper Machines Proc. of IEEE IAS Pulp and Paper Industry Conference, Charleston, South Carolina, June 16-20, 2003, pp. 145-156, IEEE Transactions On Industry Applications, Vol. 40, No. 2, March/April 2004. Expert system, paper machine drive, sensorless tension control, tension control. A rule-based expert system for the integrated control and supervision of the dry-end sections of a paper machine is proposed. This system is capable of recognizing all the normal and abnormal changes in process operating conditions, including acceleration of sections, threading of paper sheet, nip pressure activation, activation and deactivation of tension control loops, change of parent roll, and sheet break. A core part of the system is the supervision of the sensorless tension control of the dry-end sections, assuring its long-term stability. M.A. Valenzuela, J. Bentley, R.D. Lorenz
2003-020 020 Sensorless Control for Linear Compressors" International Conference on Mechatronics and Information Technology (ICMIT), December 4-6, 2003, Jecheon, Korea. J.W. Sung, C.W. Lee, J.C. Yang, D.U. Kim, G.S. Kim, T.A. Lipo, C.Y. Won, S. Choi
2003-021 021 Performance Evaluation of an Integrated Bricks-&-Buses Architecture Realization of a Power Converter EPE 2003 Conference, Toulouse, France, September 2-4, 2003. Industrial applications, Packaging, Design, Emerging Technologies, Generation of Electrical Energy It is common for families of power converter products today to be custom designed. This results in sub-optimal economic performance in terms of engineering design, packaging, manufacturing, etc. There has been a growing trend towards integrated architectures for power converter product designs. This paper presents evaluation results from the prototype of a power converter realized using an integrated architecture approach. P.S. Flannery, G. Venkataramanan
2003-022 022 Current stiff rectifiers with reverse blocking IGBTs and IGBTs with series diodes EPE 2003, Toulouse, France, September 2-4, 2003. F. Kieferndorf, M. Forster, G. Venkataramanan, T.A. Lipo
2003-023 023 Modeling and Design of a Flux Regulator for three Phase PWM Inverters with Constant SwitchingFrequency EPE 2003, Toulouse, France, September 2-4, 2003. B. Shi, G. Venkataramanan, M.C. Chandorkar
2003-024 024 Modeling and Design of a Neutral Point Regulator for a Three Level Diode Clamped Rectifier IEEE IAS 2003 Annual Conference, Salt Lake City, UT, October 12-16, 2003, vol.3, pp.1758-1765. A. Bendre, G. Venkataramanan
2003-025 025 Radial State Space Vector Modulation-A new space vector technique for reducing dc link capacitor harmonic currents in three level converters IEEE IAS 2003 Annual Conference, Salt Lake City, UT, October 12-16, 2003, vol.1, pp. 684-691. A. Bendre, G. Venkataramanan
2003-026 026 Modeling and Design of a Neutral Point Voltage Regulator for a Three Level Diode Clamped Inverter Using Multiple Carrier Modulation EPE 2003, Toulouse, France, September 2-4, 2003. This paper presents the design and implementation of a novel neutral point voltage regulator for a three level diode clamped multi level inverter, which uses a multiple carrier sine triangle modulator in conjunction with a closed loop controller for neutral point regulation. Redundant state choices are controlled via a continuous voltage offset that controls the dc current injection into the midpoint of the dc bus. Small signal dynamic models are developed for closed loop regulators with this voltage offset as the control variable. Besides maintaining dc bus voltage balance, a significant reduction is seen in the voltage distortion at the neutral point when the regulator is used and this leads to a definitive reduction in the required dc bus capacitance. Analytical, computer simulation and experimental results verifying the approach are presented in the paper. A. Bendre, G. Venkataramanan, V. Srinivasan, D. Rosene
2003-027 027 Application of Bi-State Magnetic Material to Automotive Offset-Coupled IPM Starter/Alternator Machine IAS 2003 Annual Conference, Salt Lake City, Utah, Oct. 12-16, 2003, vol. 1, pp.584-591, IEEE Transactions On Industry Applications, Vol. 40, No. 3, May/June 2004. Magnetic materials, permanent-magnet (PM) machines, rotating machine mechanical factors, synchronous machines. This paper investigates a new approach to designing high-speed interior permanent-magnet (IPM) synchronous machines using a bi-state soft magnetic material. The bi-state material can have its normally high magnetic permeability permanently reduced in localized regions to that of air by means of heat treatment. This new work significantly expands a previous investigation by considering offset-coupled IPM machines that make it possible to significantly increase the rotor speed while retaining all of the other specifications of the 6-kW starter/alternator application. Lumped-parameter models, Monte Carlo optimization, and both electromagnetic and structural finite-element analysis are used to develop new offset-coupled IPM machine designs with the new material at speeds of 40 000 r/min or higher. Results from this work demonstrate that the bi-state material offers a promising approach for designing high-speed IPM machines that offer weight and volume advantages compared to their lower speed counterparts at comparable system cost. A. El-Refaie, T.M. Jahns
2003-028 028 A Current Reconstruction Algorithm for Three-Phase Inverters Using Integrated Current Sensors in the Low-Side Switches IEEE IAS 2003 Annual Conference, Salt Lake City, Utah, October 12-16, 2003, pp. 925-932. S. Chakrabarti, T.M. Jahns, R.D. Lorenz
2003-029 029 Cogging Torque Minimization Technique for Multiple-Rotor, Axial-Flux, Surface-Mounted-PM Motors: Alternating Magnet Pole-Arcs in Facing Rotors IAS 2003 Annual Conference, Salt Lake City, Utah, October 12-16, 2003, vol.1, pp.555-561. Axial flux surface mounted PM machines, cogging torque, finite element analysis. A variety of techniques exist for reducing the cogging torque of conventional radial flux PM machines. Even though some of these techniques can be applied to axial flux machines, manufacturing cost is especially high due to the unique construction of the axial flux machine stator. Consequently, new low cost techniques are desirable for use with axial flux PM machines. This paper introduces a new cogging torque minimization technique for axial flux multiple rotor surface magnet PM motors. First, basic principles of the new technique are explored in this paper. A 3-kW, 8-pole axial flux surfacemagnet disc type machine with double-rotor-single-stator is then designed and optimized in order to apply the proposed new method. Optimization of the adjacent magnet pole-arc which results in minimum cogging torque as well as assessment of the effect on the maximum available torque using 3D Finite Element Analysis (FEA) is investigated. The minimized cogging torque is compared with several existing actual machine data and some important conclusions are drawn. M. Aydin, R. Qu, T.A. Lipo
2003-030 030 The Influence of Topology Selection on the Design of EV/HEV Propulsion Systems IEEE Power Electronics Letters, Vol.1, no.2, June 2003, pp.36-40. B.A. Welchko, J.M. Nagashima
2003-031 031 A Novel Method for Initial Rotor Position Estimation for IPM Synchronous Machine Drives, IEEE IAS 2003 Annual Conference, Salt Lake City, Utah, Oct. 12-16, 2003, vol. 2, pp.1173-1180, IEEE Transactions On Industry Applications, pp. 1369-1378, Vol. 40, No. 5, September/October 2004. Automotive applications, motion control, permanent-magnet (PM) motors, sensorless control. Novel methods for initial position estimation during startup are presented for interior permanent-magnet synchronous machine (IPMSM) drives. The magnet cavities in the IPMSM rotor create a sizable difference in the inductances of the two orthogonal rotor axes. This spatial saliency based on the rotor position makes it possible to use persistent, rotating or pulsating vector, carrier-frequency image tracking techniques to reliably identify and track the orientation of the and axes even when the rotor is at standstill. However, additional details in the saliency image must be used to identify the polarization of the magnets in order to distinguish the north and south poles. The magnet polarity is identified using magnetic saturation effects on the saliency image to uniquely identify the polarity being tracked. Carrier currents for both rotating and pulsating voltage carrier injection are derived by using IPM machine model including saturation and verified by measured carrier current components. Experimental results show that the proposed algorithms are capable of reliable and fast initial position estimation including the polarity at standstill. H. Kim, K.K. Huh, R.D. Lorenz, T.M. Jahns
2003-032 032 Comparison of Saliency-Based Sensorless Control Techniques for AC Machines IAS 2003 Annual Conference, Salt Lake City, Utah, Oct. 12-16, 2003, vol. 2, pp.1142-1149, IEEE Transactions On Industry Applications, Vol. 40, No. 4, July/August 2004. Flux angle estimation, rotor position estimation, saliency-based sensorless control. This paper analyzes saliency-based sensorless control methods for ac machines. The paper focuses on three different methods, which utilize the following signals: negative-sequence carrier-signal current, zero-sequence carrier-signal voltage, and pulesewidth-modulation-switching zero-sequence voltage. Applicability of these methods for both rotor position estimation (tracking of rotor-position-dependent saliencies) and flux position estimation (tracking of flux-dependent saliencies) is studied for each method, as well as aspects of their implementation. F. Briz, M.W. Degner, P. Garcia, R.D. Lorenz
2003-033 033 Active Thermal Control of Power Electronics Modules IEEE IAS 2003 Annual Conference, Salt Lake City, Utah, Oct. 12-16, 2003, pp. 1511-1515. Active thermal control techniques make it feasible to regulate the steady state and transient thermal-mechanical stress in power electronic modules for applications such as motor drives. On-line junction temperature estimation and manipulation of the switching frequency and current limit to regulate the losses, are used to prevent over-temperature and power cycling failures in IGBT power modules. The techniques developed in this work are used to actively control the junction temperature of the power module. This control strategy improves power module reliability and increases utilization of the silicon thermal capacity by providing sustained operation at maximum attainable performance limits. D.A. Murdock, J.E. Ramos, J.J. Connors, R.D. Lorenz
2003-034 034 Inverter Nonlinearity Effects in High Frequency Signal Injection-Based, Sensorless Control Methods IEEE IAS 2003 Annual Conference, Salt Lake City, Utah, Oct. 12-16, 2003, pp. 1157-1164. J.M. Guerrero, M. Leetmaa, F. Briz, A. Zamarron, R.D. Lorenz
2003-035 035 Initial Rotor Position Estimation of an Interior Permanent Magnet Synchronous Machine Using Carrier-Frequency Injection Methods IEEE International Electric Machines and Drives Conference, Madison, WI, June 2-4, 2003, pp. 1218-1223. J. Jeong, R.D. Lorenz, T.M. Jahns, S. Sul
2003-036 036 A Pedagogically Effective Structured Introduction to Electrical Energy Systems with Coupled Laboratory Experiences IEEE Transactions on Power Systems,Vol. 19, No. 1, February 2004. Engineering education, laboratories, power engineering education, professional communication, writing. Electrical energy conversion systems and power supply systems form an integral component of electrical and electronic systems used in residential, commercial, aerospace, transportation, and manufacturing applications. Practicing electrical engineers are often called to solve electrical energy and power-related problems. Therefore, an effective course that provides graduating electrical engineers with an energy-oriented perspective is highly desirable in today’s workplace. This paper documents a course that provides students with problem solving experience in electrical systems and electronic circuits. The paper presents the pedagogical premise, course objectives, and details of lesson and lab activities, student projects, and experiences. G. Venkataramanan
2003-037 037 Filter Networks for Long Cable Drives and Their Influence on Motor Voltage Distribution and Common-Mode Currents Annual Conference of the IEEE Industrial Electronics Society (IECON) 2003, Roanoke, Virginia, Nov. 2-6, 2003, pp.2917-2922. A.F. Moreira, P.M. Santos, T.A. Lipo, G. Venkataramanan
2003-038 038 Design Considerations for Motor-controlled Integration of a Single Phase Induction Motor Packaged Drive IEEE International Electric Machines and Drives Conference (IEMDC), Madison, WI, June 2-3, 2003, pp.1239-1244. J. Yao, J. Krase, T.A. Lipo
2003-039 039 Design and Optimization of Dual-Rotor, Radial-Flux, Toroidally-Wound, Permanent-Magnet Machines IEEE Industry Applications Society Annual Meeting, Salt Lake City, UT, Oct. 12-16, 2003, pp.1397-1404 R. Qu, T.A. Lipo
2003-040 040 3-D Finite Elements Analysis and Experimental Validation for the Consequent Pole PM Machine IEEE International Magnetics Conference (INTERMAG), Anaheim, CA, Jan. 5-9, 2004. J. Tapia, F. Leonardi, T.A. Lipo
2003-041 041 Investigation of 9-switch Dual-bridge Matrix Converter Operating under Low Output Power Facto IEEE Industry Applications Society Annual Meeting, Salt Lake City, UT, Oct. 12-16, 2003, pp.176-181. The dual-bridge matrix converter (DBMC) concept has been gaining recognition as a promising circuit alternative in recent years. Among all the DBMC topologies with reduced number of switches, the 9-switch topology shows the least number of switches and high quality waveforms. However, it has been proven that this converter can not operate safely when the output power factor is less than 0.866. This paper proposes a novel method to operate the 9-switch DBMC with low output power factor loads. In order to accomplish this task, one additional clamp circuit switch is introduced to exchange power when the output power factor is lower than 0.866. With this switch, the 9- switch DBMC can continue to provide high quality input/output waveforms when the output power factor is not too low. Theoretical analysis, simulation and experimental results are presented in the paper to verify its effectiveness. L. Wei, T.A. Lipo
2003-042 042 A Compensation Method for Dual-bridge Matrix Converters Operating under Distorted Source Voltage Annual Conference of the IEEE Industrial Electronics Society (IECON) 2003, Roanoke, Virginia, Nov. 2-6, 2003, pp.2028-2084. L. Wei, Y. Matsushita, T.A. Lipo
2003-043 043 Low-cost Current-Fed PMSM Drive System with Sinusoidal Input Currents IEEE Industry Applications Society Annual Meeting, Salt Lake City, UT, Oct. 12-16, 2003, vol.2, pp.917-924. IEEE Transactions on Industry Applications, May/June 2006. Standard low and medium power drives are based on the voltage-source converter topology. There has been less research work into dual topology drives, based on a current-fed inverter structure. Although energy storage is more efficient in capacitors than in inductors, due to some inherent advantages of current-source converter topology, and at the first place, the absence of DC link electrolytic capacitor, a current-source drive system made with a considerably reduced DC link inductor could be better low-cost solution with improved reliability, lifetime and transient response than conventional drive. This paper is about new current-fed drive topology with sinusoidal input currents, which is applied to a permanent magnet synchronous machine in low-cost applications. A threeswitch front end PWM buck rectifier with an appropriate control technique, a simple thyristor inverter at the output, together with small DC choke (which can be embedded into machine), offers virtually an inductorless integrated drive system solution and could challenge standard industry solutions. System description, analysis, design guidelines, simulated results and measured experimental results will be presented. V. Nediv, T.A. Lipo
2003-044 044 Evaluation of Shunt and Series Power Conditioning Stategies for Feeding Sensitive Loads IEEE APEC Conference, Anaheim, CA, February 22-26, 2004, pp. 1445-1451, vol. 3. B. Wang, G. Venkataramanan
2003-045 045 A Novel Dead-time Elimination Method Using Single-Input Enhanced Phase-Leg Configuration IEEE Industry Applications Society Annual Meeting, Salt Lake City, UT, October 12-16, 2003, vol.3, pp.2033-2040. S. Park, T.M. Jahns
2003-046 046 An Augmented Phase-Leg Configuration with Shoot-Through Immunity and Improvements for High-Current Operation Applied Power Electronics Conference and Exposition, 2004. APEC '04. Nineteenth Annual IEEE ,Volume: 1 , 2004, Pages: 102 - 108 Vol.1. inverters, converters, insulated gate transistor switches, protection, phase leg, gate drive The augmented phase-leg configuration (APLC) features inherent immunity to shoot-through failures and a simplified gate drive circuit that eliminates the need for control dead time. This paper addresses several key design issues that must be resolved in order to successfully apply the APLC in applications with elevated current levels (>100A). The impor- tance of minimizing key parasitic inductances is investigated, and the net reduction of the phase-leg efficiency caused by the series diode is found to be small (<1%) for bus voltages above 100Vdc. An alternative APLC topology is presented using a synchronous rectifier MOSFET that offers reduced losses by decreasing the forward conduction drop of the series diode. A combination of analysis, simulation, and experimental tests is used to confirm the basic scalability of the APLC to current levels of 100A or higher. S. Park, T.M. Jahns
2003-047 047 Synthesis of Desired AC Line Currents in Current-Sourced DC-AC Converters Proc. of IEE Conference on Power Electronics Machines and Drives (PEMD), University of Edinburgh, United Kingdom, March 31-April 2 2004, pp. 656-661, vol. 2. P. Tenca, T.A. Lipo
2003-048 048 Reduced Switch Count Double Converter Fed Wound Rotor Induction Machine Drive for Wind Energy Application IEEE International Electric Machines and Drives Conference, Madison, WI, June 2-4, 2003, pp. 1924-1931. D. Panda, T.A. Lipo
2003-049 049 A Half Power Rating Improved Three-Phase Six-Switch Boost Rectifier Using Two Half Controlled Configurations with a Common DC Bus Power Electronics Specialist Conferenc (PESC) 2003, June 15-19, 2003, Acupulco, NM, pp. 1069-1074 D. Panda, T.A. Lipo
2004-001 001 Short-Circuit Fault Mitigation Methods for Interior PM Synchronous Machine Drives using Six-Leg Inverters Proc. of the IEEE Power Electronics Specialists Conference, PESC'04, Aachen, Germany, June 20-25, 2004, pp. 2133-2139, vol. 3 This paper characterizes six-leg inverters to mitigate short-circuit faults for interior permanent magnet (IPM) synchronous machines. Key differences between bus structures in six-leg inverters are identified. For six-leg inverters employing two isolated dc links, it is shown that up to 75% of rated output power could be produced following a single-switch short-circuit fault. A magnet flux nulling control method is proposed as a response to stator winding type shortcircuit faults. This control method results in a zero-torque fault response by the motor. The important influence of the zero sequence in both the motor and inverter structure is identified and developed for this class of fault. Simulation and experimental results are presented verifying the proposed magnet flux nulling control method. B.A. Welchko, T.M. Jahns, T.A. Lipo
2004-002 002 Dynamic Modeling and Control of Three Phase Pulse Width Modulated Power Converters Using Phasors Proc. of the IEEE Power Electronics Specialists Conference, PESC'04, Aachen, Germany, June 20-25, 2004, pp. 2822-2828, vol. 4. Although the application of power electronic converters in ac power systems has been mostly limited to unidirectional loads like motor drives, various evolving applications such as power quality conditioners and distributed generation systems feature complex dynamic interactions affecting the operation of the ac power system. The focus of this paper is to present systematic technologies for modeling switching power converters in conjunction with their controls to determine their dynamic properties and assess their performance in an ac power network. The paper presents a dynamic phasor-oriented modeling technique that is readily compatible with classical power system analysis techniques. A state space model that represents the dynamic properties of the system in the magnitude-angle form is developed. The model can be used for obtaining steady state small signal dynamic properties at various operating conditions, and hence be used for design of appropriate regulators. Application of the technique is illustrated using a current source inverter example. G. Venkataramanan, B. Wang
2004-003 003 A Current Control Technique for Induction Machine Drives Using Integrated Pilot Current Sensors in the Low-Side Switches Power Electronics Specialists Conference, 2004. PESC 04. 2004 IEEE 35th Annual, Volume: 6 , 20-25 June 2004, Pages:4453 - 4459 Vol.6 S. Chakrabarti, T.M. Jahns, R.D. Lorenz
2004-004 004 Closed-Form Analysis of Adjustable Speed Drive Performance Under Input Voltage Unbalance and Sag Conditions Proc. of the IEEE Power Electronics Specialists Conference, PESC'04, Aachen, Germany, June 20-25, 2004, pp. 469-475, vol. 1. Industry Applications, IEEE Transactions on Volume: 42 Issue: 3 May-Jun 2006 Page(s): 733- 741 Voltage unbalance or sag conditions generated by the line excitation can cause the input rectifier stage of an adjustable-speed drive (ASD) to enter single-phase rectifier operation. This degradation of the input power quality can have a significant negative impact on the induction machine performance characteristics. This paper provides an approximate closed-form analysis of the impact of line voltage sags and unbalance on the induction machine phase voltages, currents, and torque pulsations for a general-purpose ASD consisting of a three-phase diode bridge rectifier, dc link, and PWM inverter delivering constant Volts-per-Hertz excitation. Attention is focused on the impact of the dominant 2nd harmonic of the line frequency that appears in the dc link voltage during the sag/unbalance conditions, neglecting the impact of the other higher-order harmonics. In addition to the closed-form analytical results that assume constant rotor speed, both simulation and experimental results are presented that confirm the key analytical results, including the dominance of the 2ndharmonic in the resulting torque pulsations. The analytical results can be used as a valuable design tool to rapidly evaluate the approximate impact of unbalance/sag conditions on ASD machine performance. K. Lee, T.M. Jahns, W.E. Berkopec, T.A. Lipo
2004-005 005 Design-oriented Analysis of DC Bus Dynamics in Adjustable Speed Drives Under Input Voltage Unbalance and Sag Conditions Proc. of the IEEE Power Electronics Specialists Conference, PESC'04, Aachen, Germany, June 20-25, 2004, pp. 1675-1681, vol. 2 Utility power quality problems like input voltage unbalance and sag conditions severely stress diode bridge rectifiers used in adjustable-speed drive (ASD) equipment. The key phenomenon that causes these problems is the transition of the rectifier from three-phase to single-phase operation. This is accompanied by increased harmonic currents that shorten the dc-bus capacitor life span. In addition, the bus ripple voltage causes undesired harmonic phase currents in Volts-per-Hertz ac drives, leading to elevated machine heating and the generation of pulsating torque at the second line harmonic (i.e., 120 Hz). This paper develops closed-form expressions that lay a solid foundation to analyze and quantify these phenomena, making it much easier to investigate alternative mitigation strategies. The paper identifies the boundary conditions that determine the entry of the rectifier stage into single-phase operation under unbalanced voltage sag conditions. Closed-form equations for the dc bus voltage and current are derived valid for finite line impedance, finite bus capacitance and varying loads. These expressions make it possible to conveniently conduct parametric studies of the system behavior under wide ranges of operating conditions without resorting to time-consuming time-domain simulations. Simulation and experimental tests are used to verify the accuracy and effectiveness of the analysis by comparing key predicted power quality performance indices (e.g., input power factor, current crest factor, THD) to simulated and measured values using a 5 hp ASD system. K. Lee, G. Venkataramanan, T.M. Jahns
2004-006 006 Microgrid: A Conceptual Solution Proc. of the IEEE Power Electronics Specialists Conference, PESC'04, Aachen, Germany, June 20-25, 2004, pp. 4285-4290, vol. 6. microgrid, distributed generation, CHP, intentional islanding, voltage droop, power vs. frequency droop, inverters Application of individual distributed generators can cause as many problems as it may solve. A better way to realize the emerging potential of distributed generation is to take a system approach which views generation and associated loads as a subsystem or a “microgrid”. During disturbances, the generation and corresponding loads can separate from the distribution system to isolate the microgrid’s load from the disturbance (providing UPS services) without harming the transmission grid’s integrity. This ability to island generation and loads together has a potential to provide a higher local reliability than that provided by the power system as a whole. In this model it is also critical to be able to use the waste heat by placing the sources near the heat load. This implies that a unit can be placed at any point on the electrical system as required by the location of the heat load. P. Piagi, R.H. Lasseter
2004-007 007 Reduced Cost Current-Source Topology Improving the Harmonic Spectrum Through On- Line Functional Minimization Proc. of the IEEE Power Electronics Specialists Conference, PESC'04, Aachen, Germany, June 20-25, 2004, pp. 2829-2835, vol. 4. The paper presents a Current-Source Inverter (CSI) topology tailored for large multi-megawatt wind turbine applications. The cable distance between the generator and the mains enables the realization of a significant portion of the DClink inductance. In order to improve the efficiency and to allow the possible utilization of rugged inexpensive Thyristors, PWM modulation is not used in the main conversion chain. Unity fundamental power factor at the mains is guaranteed at any load condition while the 5th and 7th harmonics of the mains line currents are reduced by choosing a proper nominal operating point for the turbine. Further harmonic reduction is achieved through an active filter controlled via a newly proposed methodology suitable for Digital Signal Processor (DSP) implementation. Such a controller relies on a real-time minimization of a proper functional and is capable of implementing true-feedback current regulation. A part of design simulation results, aimed at constructing a 10 kW prototype, are presented. P. Tenca, T.A. Lipo
2004-008 008 A Low Cost 500 Watt Motor and Drive for HVAC Applications: UW-Madison's Design for the Future Energy Challenge Proc. of the IEEE Power Electronics Specialists Conference, PESC'04, Aachen, Germany, June 20-25, 2004, pp. 376-382, vol. 1. Participants in the 2003 International Future Energy Challenge attempted to design a single phase input, 500 watt adjustable speed motor and drive with a million unit volume production target cost of $40. The UW-Madison team approach is presented in this paper. A soft magnetic composite segmented stator PM-BLDC design and back-emf sensing drive is proposed. Manufacturing cost is the main constraint in this design. Educational aspects are also discussed. T.P. Bohn, N.R. Brown, R.D. Lorenz, T.M. Jahns
2004-009 009 Fault Interrupting Methods and Topologies for Interior PM Machine Drives EPE Power Electronics and Motion Control Conference, EPE-PEMC'04, Sept. 2004, Riga, Latvia. IEEE Power Electronics Letters, Vol. 2, Issue 4, December 2004, pp. 139-143 Inverter shutdown, protection, short-circuit fault, uncontrolled generator, variable speed drive. This letter investigates methods to interrupt the phase currents induced when interior permanent magnet (IPM) machine drives suffer short-circuit or uncontrolled generator mode faults. A fault-tolerant silicon switch is proposed in which the antiparallel diode in a reverse-blocking inverter switch is replaced by a thyristor. A reduced-parts-count fault-interrupting topology is also proposed which consists of delta-connected thyristors inserted at the center star point of wye-connected IPM machine stator windings. Control of the proposed reduced parts-count fault-tolerant drive is discussed and simulation results are presented to verify operation of the proposed topology. B. Welchko, T.M. Jahns, T.A. Lipo
2004-010 010 Axial Flux Permanent Magnet Disc Machines: A Review, Symposium on Power Electronics Symposium on Power Electronics, Electrical Drives, Automation, and Motion (SPEEDAM) 2004, Capri, Italy, June 16-18, 2004. Axial flux permanent magnet (PM) machines are being developed for many applications due to their attractive features. An extensive literature exists concerning the design of a variety of types of axial flux PM machines. An overview of axial flux, slotless and slotted various PM machines are presented in this paper. Machine structures, advantages and features of the Axial Flux PM machine (AFM) are clarified. Several interesting novel axial flux machine structures are also covered from a variety of perspectives. M. Aydin, S. Huang, T.A. Lipo
2004-011 011 A Virtual Translation Technique to Improve Current Regulators for Salient-Pole AC Machines Proc. of the IEEE Power Electronics Specialists Conference, PESC'04, Aachen, Germany, June 20-25, 2004, pp. 487-493, vol. 1. Current regulator, cross-coupling, decoupling, complex vector, interior permanent magnet synchronous machine (IPMSM) This paper presents a synchronous frame current regulator for salient-pole AC machines which is insensitive to both parameters and synchronous frequencies. The transformation from stationary to synchronous frame is known to produce a frame-dependent cross-coupling term, which results in degradation in current response at high speeds and is represented as an asymmetric pole in the complex vector form of such systems. The asymmetric pole close to right half plane (RHP) in the complex vector s-domain cannot be perfectly canceled by parameter-based design of PI controllers due to parameter variation. Complex vector design synchronous frame PI current regulator with a virtually translated asymmetric pole is shown in this paper to reduce the parameter sensitivity and to improve disturbance rejection. The current regulator with the virtually translated pole have been analyzed in complex vector form for non-salient-pole AC machine and in scalar form for salient-pole AC machines. It has been shown to yield comparable performances in both cases. This paper includes experimental verification of the performance of the proposed current regulator for an IPMSM. H. Kim, R.D. Lorenz
2004-012 012 Investigation of the Dual Bridge Matrix Converter Operating Under Boost mode EPE Power Electronics and Motion Control Conference, EPE-PEMC'04, Sept. 2004, Riga, Latvia. The dual bridge matrix converter can create high quality input/output waveforms as the normal double bridge converter with less switches, simpler clamp circuit and easier control. Moreover, it can also operate with a common bus-multiple inverter fed load condition. As a result, a more flexible and compact design can be made with this topology. This paper investigates the operation of a dual-bridge matrix converter (DBMC) under the boost mode. The converter operates at several hundred hertz fundamental frequency at both the input and two output sides. The high frequency operation at both sides further reduces the size and the weight of the system. Finally, theory analysis and simulation results are presented in the paper to verify its effectiveness. L. Wei, T.A. Lipo
2004-013 013 Field Weakening of Permanent Magnet Machines - Design Approaches EPE Power Electronics and Motion Control Conference, EPE-PEMC'04, Sept. 2004, Riga, Latvia. PermanentMagnet (PM) machineshavebeendevelopedfor numerous applications due to their attractive features especiallyafter the development of NdFeB magnets. However, their complicated controllets the researchers develop new machine structures witheasy field control. New alternative PM machine topologies with field weakening or hybrid excitation have been introduced in the literature for years to eliminate the ef ects of problems associated with the cumbersome field weakening techniques used in conventional PM machines. This paper reviews the field weakening of PM machines covered from machine’s perspective.Machine structures and features of each structure are clarified for both radial and axial airgap PM machines studied thus far. T.A Lipo, M. Aydin
2004-014 014 Magnet Flux Nulling Control of Interior PM Machine Drives for Improved Response to Short Circuit Faults IEEE IAS Annual Meeting, IAS'04, October 3-7, 2004, Seattle, WA, USA, p. 261-267, vol. 1. IEEE Transactions on Industry Applications, Vol. 42, No. 1, pp. 113-120, Jan/Feb 2006. Current regulation, inverter shutdown, magnet flux, short-circuit fault, variable-speed drive. This paper proposes a control method to null the magnet flux in an interior permanent-magnet (IPM) motor following short-circuit-type faults in either the inverter drive or motor stator windings. Phase-based control is employed to implement the flux-nulling-control method so that it is possible to take advantage of a zero-sequence current in order to minimize the current in the shorted phase. It is shown that phase-based control results in a smaller induced current than when employing a synchronous-frame dq0 current regulator. The induced torque is also less than that when employing a purposely commanded symmetrical short circuit in response to a short-circuit-type fault. In the paper, the complete magnet-flux-nulling-control algorithm is derived with reference to the proposed phase-current-control method. The impact of controlling the zero-sequence current on the resulting phase currents is presented. Both simulation and experimental results are presented, verifying the operation of the proposed methods. B.A Welchko, J. Wai, T.M. Jahns, T.A. Lipo
2004-015 015 Reduction of Parameter Sensitivity in and Induction Motor Current Regulator using Integrated Pilot Sensors in the Low-Side Switches IEEE IAS Annual Meeting, IAS'04, October 3-7, 2004, Seattle, WA, USA, pp. 647-654, vol. 1. IEEE Transactions on Industry Applications, Vol. 41, No. 6, pp 1656-1666, Nov/Dec 2005. Decoupling voltage, indirect field-oriented control, integrated pilot current sensor, three-phase induction motor drives. A closed-loop synchronous-frame current regulator for an induction machine drive that is capable of delivering high-quality performance characteristics using integrated pilot current sensors in the three low-side switches of a three-phase bridge inverter has been developed. However, the necessary current reconstruction exhibits sensitivity to errors in the machine parameters, which has been documented during this investigation. This paper presents a technique for introducing a gated integrator into the controller gain amplifier that compensates for parameter errors using feedback information from all three of the phase currents during the periodic intervals when it is available. A numerical singularity in the current reconstruction algorithm during light-load operation is overcome by introducing an alternative first-order current estimator that is activated over narrow angular spans of the fundamental component vector rotation. This paper also presents an in situ technique to compensate gain differences between the three pilot devices in the inverter unit. The effectiveness of these improvements is verified using experimental results. S. Chakrabarti, T.M. Jahns, R.D. Lorenz
2004-016 016 Experimental Evaluation of the Endangerment of Ball Bearings due to Inverter-Induced Bearing Currents IEEE IAS Annual Meeting, IAS'04, October 3-7, 2004, Seattle, WA, USA, pp. 1989-1995, vol. 3. variable speed drives, inverter-induced bearing currents, apparent bearing current density, bearing fluting Statements on the mechanism of the endangerment of bearings due to inverter-induced bearing currents nearly do not exist today. Therefore, a series of 22 test runs for bearing damage assessment was carried out. The influence of bearing current amplitude and type, calculated apparent bearing current density, time of operation and inverter switching frequency on bearing damage was investigated. The degree of electrical bearing stress “W” was introduced. The degree of melting of the bearing race surface and the grade of reduction of the carboxylic acid, which is an indicator for the deterioration of the grease, depend on W. A. Muetze, A. Binder, H. Vogel, J. Hering
2004-017 017 Optimal Flux Weakening in Surface PM Machines Using Concentrated Windings IEEE IAS Annual Meeting, IAS'04, October 3-7, 2004, Seattle, WA, USA, pp. 1038-1047, vol. 2. A design approach is presented for achieving optimal flux weakening operation in surface PM synchronous machines by properly designing the machine's stator windings using concentrated, fractional-slot stator windings. This technique makes it possible to significantly increase the machine inductance in order to achieve the critical condition for providing wide speed ranges of constant-power operation. The conditions for optimal flux weakening can be achieved while simultaneously delivering sinusoidal back-emf waveforms and low cogging torque. A closed-form analytical model is described that can be used to design SPM machines to achieve optimal flux weakening conditions. This technique is applied to design a 6kW SPM machine that achieves constant-power operation over a wide speed range. Performance characteristics of this machine are compared using both closed-form and finite element analysis. A.M. El-Refaie, T.M. Jahns
2004-018 018 Calculation of Circulating Bearing Currents in Machines of Inverter-Based Drive Systems IEEE IAS Annual Meeting, IAS'04, October 3-7, 2004, Seattle, WA, USA, pp. 720-726, vol. 2. variable speed drives, inverter-induced circulating bearing currents, common mode voltage The high frequency circulating bearing current that may occur in machines of inverter-based drive systems can be described by an eddy-current model. The parameters of an equivalent circuit are derived from the model. The ratio between bearing current and common mode current amplitudes for different machines is calculated. The theoretical maximum ratio is about 0.35. Copper loops applied for bearing current measurement may decrease the circulating bearing currents up to almost 40 %. A. Muetze, A. Binder
2004-019 019 Parallel Operation of Voltage Source Inverters with Minimal Intermodule Reactors IEEE IAS Annual Meeting, IAS'04, October 3-7, 2004, Seattle, WA, USA, p. 156-162, vol. 1 Realization of large horsepower motor drives using parallel-connected voltage source inverters rated at smaller power levels would be highly desirable. A robust technique for such a realization would result in several benefits including modularity, ease of maintenance, n+1 redundancy, reliability, etc. Techniques for parallel operation of voltage source inverters with relatively large load inductance have been well established in the field of UPS systems. This paper presents an approach to such realization using minimal passive components along with an active current balancing strategy for motor drive systems. Analytical models, computer simulations and experimental results are presented. B. Shi, G. Venkataramanan
2004-020 020 DC Bus Electrolytic Capacitor Stress in Adjustable-Speed Drives under Input Voltage Unbalance and Sag Conditions IEEE IAS Annual Meeting, IAS'04, October 3-7, 2004, Seattle, WA, USA, pp. 2560-2567, vol. 4 This paper analyzes the effects of the input voltage unbalance and sags on the dc bus electrolytic capacitors in adjustable-speed drives (ASDs) in order to predict their impact on expected capacitor lifetime. The key phenomenon that causes these problems is the transition of the rectifier stage from threephase to single-phase operation. Since the ESR (equivalent series resistance) increases at low frequencies, the low-order harmonic current components (120 Hz, 240 Hz, etc.) contribute disproportionately to the capacitor power losses and temperature rise, resulting in reduced lifetime. Closed-form expressions are developed for predicting these effects including the impact of finite line impedance, finite bus capacitance, and varying load. The impact of inverter SVPWM (space vector pulse width modulation) switching on the capacitor loss is also included. Simulations and experimental tests are used to verify the accuracy and effectiveness of the closed-form analysis using a 5 hp ASD system. K. Lee, T.M. Jahns, G. Venkataramanan, W.E. Berkopec
2004-021 021 AC Brushless Drive With Low Resolution Hall-Effect Sensors For An Axial Flux PM Machin IEEE IAS Annual Meeting, IAS'04, October 3-7, 2004, Seattle, WA, USA, pp. 2382 - 2389, vol. 4. Low resolution sensors; position and velocity estimation; vector-tracking observer; axial flux PM machine An ac brushless drive in which Hall effect sensors are used as rotor position sensors is presented in this paper. Three different methods to obtain high resolution position information from the low resolution sensors are described and compared through simulation and some preliminary experimental testing. The proposed control algorithm’s most innovative feature is it’s adaptability to the whole speed range, including start-up, when using any of the three estimation algorithms. The entire control algorithm has been implemented and tested in order to drive an axial-flux PM machine for home appliance applications. F. Giulii Capponi, G. De Donato, L. Del Ferraro, O. Honorati, M.C. Harke, R.D. Lorenz
2004-022 022 Load Invariant Sensorless Control of a SRM Drive Using High Frequency Signal Injection IEEE IAS Annual Meeting, IAS'04, 3-7 October, 2004, Seattle, WA, USA, pp. 1632-1637, vol. 3. High frequency signal injection, position estimation, sensorless control, switched reluctance machine drives. This paper presents a load invariant position estimation technique for Switched Reluctance Machine (SRM) drives based on high frequency signal injection methods. A high frequency rotating voltage vector is superimposed on the main excitation. The spatial saliency information is extracted using synchronous reference frame filtering. A robust position estimate is achieved by using an observer to track the spatial saliency. The theoretical spatial saliencies for a three–phase SRM can be derived using the doubly salient model of the machine. The proposed method is capable of providing continuous dynamic position estimation from zero to mid-range speeds with negligible load dependency. E. Kayikci, M.C. Harke, R.D. Lorenz
2004-023 023 Design Considerations and Experimental Results of an Axial Flux PM Motor With Field Control ICEM, September 5-8, 2004, Cracow, Poland Design considerations and experimental evaluation of a field controlled disc type axial flux surface mounted PM machine is presented in this paper. The concept of airgap flux control as well as machine structure is clarified. In order to evaluate the new axial flux machine topology an experimental system set-up is devised and discussed. The inverter used, control strategy and test system set-up are also explained. The detailed experimental results of the prototype machine and comparison between the FEA and the test results are also presented. M. Aydin, J. Yao, E. Kayikci, S. Huang, T.A. Lipo
2004-024 024 Power Electronics Modules for Inverter Applications using Flip-Chip on Flex-Circuit Technology IEEE IAS Annual Meeting, IAS'04, 3-7 October, 2004, Seattle, WA, USA, pp. 1526-1533, vol. 3 power modules, planar interconnection packaging, active gate drives, silicon carbide semiconductors A power packaging platform that features flexcircuit interconnection of power dies and flip-chip soldering technology has incorporated several advanced features including active gate drive technology with adjustable dv/dt control, a selfboost charge pump for the high-side gate drive power supply, and isolated giant magnetoresistive (GMR) devices for current sensing and active Tj and ?Tj control. The packaging platform, previously demonstrated suitably for 42V/16A automotive applications, has been extended to 400V/10A inverter applications. Experimental test results demonstrate electrical performance measured under both double-pulse and 10% duty-ratio conditions. A comparison of the switching characteristics of IGBT test modules implemented with both Si and SiC free-wheeling diodes demonstrates the performance advantages that are possible with SiC power devices. H.N. Shah, Y. Xiao, T.P. Chow, R.J. Gutmann, E.R. Olson, S-H. Park, W-K. Lee, J.J. Connors, T.M. Jahns, R.D. Lorenz
2004-025 025 Modeling Effects of Voltage Unbalances in Industrial Distribution Systems with Adjustable Speed Drives IEEE IAS Annual Meeting, IAS'04, 3-7 October, 2004, Seattle, WA, USA, pp. 2579-2586, vol. 4 AC Adjustable Speed Drives (ASDs) have become the primary choice for most new and retrofit precision motorcontrol applications with increased system efficiencies and reduced system losses. The significant increase in the use of ASDs brings the need for understanding compatibility issues between them and their electrical environment in order to design the electrical systems appropriately. Even though there have been numerous studies on ASD effects on power systems, models for predicting the effect of the source voltage sags or unbalance have been limited. This paper is devoted to analyze the characteristics of power quality indices such as input power factor, input current crest factor (CF) and the distribution transformer Kfactor for practical ASD systems under input voltage unbalance and sag conditions. The relationships between the unbalanced input voltages and input currents, the input inductance and the input current unbalance, the input inductance and the input power factor, crest factor, transformer K-factor are explored for 5 hp, 100 hp and 600 hp power distribution systems with ASDs. The results can be used as a design guide for power distribution system design with ASDs. Theoretical derivations, simulation and experimental results are presented in this paper. K. Lee, Jahns Venkataramanan, T.M.
2004-026 026 Soft Magnetic Composites for AC Machines - A Fresh Perspective Power Electronics and Motion Control Conference, Sept. 2-4, 2004, Riga Latvia Soft magnetic composites (SMCs) have opened up new possibilities for the design of both DC and AC machines. Since SMCs are isotropic, machine topologies such as claw pole machines, transverse flux machines and the like, which have three dimensional flux density patterns have attracted the most attention. Very little effort has gone into improving the performance of conventional AC machines such as cylindrical rotor permanent magnet machines. This paper proposes new options for design of conventional machines which efficiently utilize the SMC material. T.A. Lipo, S.M. Madani, R. White
2004-027 027 Synchronous Frame PI Current Regulators in a Virtually Translated System IEEE IAS Annual Meeting, IAS'04, 3-7 October , 2004, Seattle, WA, USA, pp. 856-863, vol. 2 Current regulator, cross-coupling, decoupling, complex vector, interior permanent magnet synchronous machine (IPMSM) This paper presents a virtual translation technique for current regulation for AC machines. A virtual physical parameter is employed to effectively translate the system pole to achieve fast and robust dynamics. Applying this technique to conventional synchronous frame current regulators reduces parameter sensitivity and improves robustness. The current controllers are redesigned in the virtually translated system. Current regulators adopting the technique have been analyzed in complex vector form for symmetric AC machines and in scalar form for salient-pole AC machines. Several current regulators using this technique have been experimentally evaluated for different operating conditions in an IPMSM drive. H. Kim, R.D. Lorenz
2004-028 028 Robust Estimator Design for Signal Injection-Based IPM Synchronous Machine Drives IEEE IAS Annual Meeting, IAS'04, 3-7 October, 2004, Seattle, WA, USA, pp. 957-963, vol. 2 Position estimation, self-sensing, sensorless control This paper analyzes the design choices taken when designing a carrier-signal-based self-sensing position and speed estimation strategy for IPM drives. The balance between the noise generation and the load disturbance rejection process is analyzed, since this balance is essential for robustness. An extended closed loop observer is introduced to improve robustness during load changes, and guidelines for choosing bandwidth for filters is given. A scalar current observer is essential for robust elimination of the fundamental component. An improved structure for the observer is presented and discussed, which improves the impact from transients from the BSF filters. P. Vadstrup, R.D. Lorenz
2004-029 029 Carrier Signal Injection Based Sensorless Control Methods for IPM Synchronous Machine Drives IEEE IAS Annual Meeting, IAS'04, 3-7 October, 2004, Seattle, WA, USA, pp. 977-984, vol 2 Sensorless control, high frequency injection, permanent magnet motors, motion control, automotive applications This paper presents a comparison of carrier signal injection methods for sensorless torque and motion control of interior permanent magnet synchronous machine (IPMSM) drives. Rotor position can be identified at standstill and higher speeds by using one of two spatial saliency based high frequency carrier signal injection methods: rotating vector in the stationary fream or pulsating vector in the estimated rotor frame. Carrier currents for both rotating and pulsating voltage carrier injection are derived by using an IPMSM model for high frequency. An appropriate carrier signal extraction and a spatial saliency tracking scheme for both injection methods are developed for robust sensorless control. By interfering with the spatial saliency, saturation-induced saliencies act as disturbances to the rotor position estimation. Modeling, measurement, and analysis of the undesirable saturationinduced saliencies are presented for both carrier signal injection methods. H. Kim, R.D. Lorenz
2004-030 030 A Synchronous Back-to-Back Intertie using the Vector Switching Converter Thirty-Sixth Annual North American Power Symposium (NAPS), August 9-10, 2004, Moscow, Idaho, USA FACTS, back-to-back ties, vector switching converters, power flow control. This paper presents an application of the Vector Switching Converters (VSC), configured as a synchronous backto-back intertie. When operating in synchronous systems, a VSC back-to-back intertie can offer functional capabilities similar to the traditional HVdc ties or the unified power flow controller. It can provide active power control, reactive power control, and phase-shifting capabilities. Operating principles, equivalent circuits, and design considerations are discussed. Detailed computer simulation results, along with the limitations of the proposed approach are also presented. F. Mancilla-David, G. Venkataramanan
2004-031 031 A Simple Model For Flux Weakening in Surface PM Synchronous Machines Using Back-to-Back Thyristors IEEE Power Electronics Letters, JUNE 2004, pp. 54-57, vol. 2, issue 2. Flux weakening, permanent magnet, synchronous machines, thyristors, triacs. Flux weakening in surface permanent magnet (PM) synchronous machines is revisited in this letter. The condition for achieving infinite constant power speed ratio (CPSR) is explained from the machine equivalent circuit and phasor diagram point of view. Back-to-back thyristors, or triac, switches feeding the three phases of a surface PM synchronous machine will be shown to be equivalent to a simple series reactance with respect to fundamental component behavior. Using such switches is equivalent to adding a series inductance to the machine. This additional inductance helps extend the CPSR of surface PM synchronous machines. This is significant because extending the CPSR of surface PM machines is usually a challenging task due to the presence of low-permeability surface magnets and the resulting low machine inductance. A.M. El-Refaie, D.W. Novotny, T.M. Jahns
2004-032 032 Practical Rules for Assessment of Inverter-Induced Bearing Currents in Inverter-Fed AC-Motors up to 500 kW 16th International Conference on Electrical Machines (ICEM), 5-8 September 2004, Crakow, Poland The influence of different parameters of a variable speed drive system on the phenomena of inverter-induced bearing currents has been studied under exactly the same conditions on inverter-operated acmotors 1 kW to 500 kW. Detailed modeling may not always be applicable with practical applications in the field, where many parameters might be unknown. Therefore, the most important correlations are summarized in the form of a flow-chart. This flowchart might serve as a tool for engineers to estimate the endangerment of a drive system due to inverter-induced bearing currents, where detailed knowledge of the different design parameters is not available. The flowchart also summarizes possible mitigation techniques to prevent bearing damage. A. Muetze, A. Binder
2004-033 033 A Multi-Physics Model of Planar Electro-Active Polymer Actuators Proc. of IEEE IAS Conf., October 3-7, 2004, Seattle, WA, USA, pp 2125-2132. Actuators, polymer actuators, electro-active polymer actuators Dielectric electro-active polymers (EAP) have a significant deformation response to electrical stimulation. The ease of fabrication of these materials makes them very suitable for product-integrated actuators. Existing electromechanical models do not fully integrate all aspects of the physical behavior needed to design such actuator systems. This paper presents an fully integrated, multi-physics model for such EAP actuators, combining the electrostatic properties of the electrical circuit with the compliant electrodes, the actual force output in the translation direction, nonlinear elastic behavior and damping of the polymer material. The capabilities of the developed model are discussed and verified with lab experiments. C. Hackl, H.-Y. Tang, R.D. Lorenz, L.-S. Turng, D. Schroder
2004-034 034 Design and Parameter Effect Analysis of Dual-Rotor, Radial-Flux, Toroidally-Wound, Permanent-Magnet Machine IEEE Transactions on Industry Applications, Vol. 40, No. 3, May/June 2004, pp. 771-779 Parameter effect analysis, permanent-magnet(PM) machine design, radial-flux, toroidally wound, permanent-magnet (RFTPM) machine. A novel machine family—the dual-rotor, radial-flux, toroidally wound, permanent-magnet (RFTPM) machine—has been proven in a previous paper to be able to improve the machine efficiency and boost the torque density. This paper will present the key design equations and design procedure of the RFTPM machines, analyze parameter effects on machine performance, and give design guidelines to achieve specific design objectives. In addition, finite-element analysis is employed to prove the effectiveness of the design equations and find the machine overload capability. Experimental measurements of a prototype, which match the design specifications well, verify the effectiveness of the design equations. R. Qu, T.A. Lipo
2004-035 035 Sizing Equations and Power Density Evaluation of Dual-Rotor, Radial-Flux, Toroidally Wound, Permanent-Magnet Machines 16th International Conference on Electrical Machines, ICEM 200r, Cracow, Poland, Sept 2004. RFTPM Machine, Sizing Equations, PM Machine, Power Density A novel machine family – the dual-rotor, RadialFlux, Toroidally wound, Permanent-Magnet (RFTPM) machine – has been proven in a previous paper to be able to improve the machine efficiency and boost the torque density. This paper will develop the sizing equations for the RFTPM machines based on the machine overall sizes, material properties, and electrical and magnetic loadings to provide a quick method to evaluate the RFTPM machines. The accuracy of the developed sizing equations is proven by a prototype machine. A comparison among induction, axial-flux PM, and RFTPM machines are made based on the sizing equations. The RFTPM structure appears to be capable of substantially higher power density than equivalent induction machines, and more potential to achieve higher torque density than axialflux PM machines. R. Qu, T.A. Lipo
2004-036 036 Three-phase vector switching converters for power flow control Electric Power Applications, IEEE Proceedings - Volume 151, Issue 3, May 8, 2004, pp. 321 - 333. As congestion in AC power transmission systems increases due to technical limitations, environmental pressures, economic necessities and developmental demands, devices with ability to control power flow with much greater ease than presently possible would be highly desirable. Furthermore, devices that channel power flow in the network to fulfill contractual obligations for purchase agreements between power producers and consumers would facilitate improved operation of the power system in the emerging deregulated scenario. Generally, electronic control devices for directing power flow in AC systems have been realised using phase-controlled reactors in conjunction with switched capacitors, voltage source and current-source DC-link rectifiers/ inverters have been applied on a point-to-point basis. Three phase vector switching converters are introduced as an alternative approach for realising power flow control in more complicated interconnections. These converters are seen to have the potential to be configured at arbitrary intertie points in a three-phase power system to route power flow in a complex power system. Operating principles, equivalent circuit models, simulation and experimental waveforms are presented along with examples. G. Venkataramanan
2004-037 037 A Control Scheme in Hybrid Synchronous-Stationary Frame for PWM AC/DC Converter under Generalized Unbalanced Operating Conditions IEEE IAS Annual Meeting, IAS'04, 3-7 October, 2004, Seattle, WA, USA IEEE Transactions on Industry Applications May/June 2006 component; ac/dc converter, unbalance, hybrid synchronous frame controller This paper proposes a new control scheme of improved transient response for the pwm ac/dc converter under generalized unbalanced operating conditions. The overall bandwidth diminishing filter/functional block for extracting positive and negative sequence components have been avoided by employing dual current regulators in positive and negative rotating synchronous frames. The steady-state error due to 120 Hz ac signals has been reduced by employing a resonant gain path in the current regulator. This paper also proposes simplified current reference calculation scheme in the regulation of instantaneous active/reactive power. Compared to the previous works, the proposed control method has better transient response in compensation for generalized unbalanced operating conditions (unbalanced input supply and unbalanced input impedances) of wide range while still satisfying unity input power factor correction and ripple-free dc output voltage regulation without adding any external hardware. The proposed control system has been analyzed and tuned based on the ac small signal perturbed model under unbalance. Simulation and experimental results confirm the proposed control method under severe unbalance operating conditions. Y. Suh, T.A. Lipo
2005-001 001 Conversion Topology for Reducing Failure Rate and Life-Cycle Costs of High-Power Wind Turbines" 43rd Aerospace Sciences Meeting and Exhibit, 10-13 January 2005, Reno, Nevada. The paper presents a Current-Source Inverter (CSI) topology tailored for large multimegawatt wind turbine applications. The cable distance between the generator and the mains enables the realization of a significant portion of the DC-link inductance. In order to improve the efficiency and to allow the possible utilization of rugged inexpensive Thyristors, PWM modulation is not used in the main conversion chain. Unity fundamental power factor at the mains is guaranteed at any load condition while the 5th and 7th harmonics of the mains line currents are greatly reduced by choosing a proper nominal operating point for the turbine. Further harmonic reduction is achieved through an active filter controlled via a newly proposed methodology suitable for Digital Signal Processor (DSP) implementation. Such a controller relies on the real-time minimization of a proper functional and is capable of implementing true-feedback current regulation. A part of design simulation results, aimed at building a 10 kW prototype are presented together with the description of its experimental setup currently in construction. P. Tenca, T.A Lipo
2005-002 002 Analysis of Optimal Stator Concentric Winding Patterns Design IEMDC '05, 15-18 May, 2005, San Antonio, TX, USA, pp. 94-98, vol. 1. Concentric Windings, MMF, Harmonics, Induction Motor Windings Most small induction motors in current use employ concentric windings which have equal numbers of turns per coil. An optimal choice of turns can achieve better distribution of MMF in the gap while keeping the turns in each slot essentially the same. In this paper, the air gap Magnetic Motive Force (MMF) harmonics of electrical machine created by the stator concentric windings with sinusoidal current injection are investigated. The air gap MMF is modeled ideally by a linear winding function, which simplifies the MMF expression significantly by neglecting the slot effects and saturation for uniform air-gap machines. By evaluating the harmonic property of the synthesized three phase air gap MMF waveform, optimal winding patterns can be developed for conventional choices of phase belts. W. Ouyang, T.A. Lipo, A. El-Antably
2005-003 003 A Pulse Width Modulated AC Link Unified Power Flow Controller IEEE Power Engineering Society 2005 General Meeting (IEEE-PES 2005), 12-16 June, 2005 San Francisco, CA, USA FACTS, UPFC, ac/ac converters, power flow control, vector switching converters. This paper proposes a new FACTS device: the -Controller. Based on the Vector Switching Converters, the -Controller offers functional capabilities similar to the Unified Power Flow Controller, in the sense that it can independently control the active and reactive power flow through a transmission line. The control function, however, is realized by direct ac conversion without frequency change, adopting the strategy of pulse width modulation. Operating principles, equivalent circuits, and design considerations are discussed. A detailed computer simulation is used to validate the approach. F. Mancilla-David, G. Venkataramanan
2005-004 004 Implementation of a Fast Initial Position and Magnet Polarity Estimation for PM Synchronous Machines in Traction and White Goods Applications IEEE Electro Information Technology Conference, Lincoln, NE, 22-25 May, 2005 A general solution for initial position and magnet polarity estimation on PM machines is presented. The technique is based on carrier frequency signal injection and proves to be fast, simple and parameter insensitive. It is applied to both salient and very low saliency PM synchronous machines of different power levels. An important step to understanding the implementation is to map the saliency and magnet polarity information as a function of rotor position. A state filter topology is proposed to ensure fast, smooth and robust convergence of the initial position and magnet polarity estimation for a SPMSM with an extremely low saliency ratio. Test results demonstrate consistent performance across different machine types. M.C. Harke, D. Raca, R.D. Lorenz, E. Schlevensky
2005-005 005 Design Considerations for Reactive Elements and Control Parameters for Three Phase Boost Rectifiers Electric Machines and Drives 2005 IEEE International Conference on May 15, 2005 Page(s):1757 - 1764 The three phase boost rectifier is gradually emerging to be the choice of approach for improving power quality for high power motor drive applications. Although the topology of the converter, its application and control techniques have been known for decades, a systematic design oriented model has not been established in the literature. This paper presents the development of a design-oriented model that addresses clearly the choice of reactive elements and control parameters in a coupled fashion. The model is verified using computer simulations and experimental verifications. B. Shi, G. Venkataramanan, N. Sharma
2005-006 006 Scalability of Surface PM Machines with Concentrated Windings Designed to Achieve Wide Speed Ranges of Constant-Power Operation Electric Machines and Drives, 2005 IEEE International Conference on May 15, 2005 Page(s):1703 - 1709 permanent magnet synchronous motors, flux weakening, fractional-slot concentrated windings, scalability. Previous work has shown that it is possible to design surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings to achieve wide speed ranges of constant-power operation. A closed-form analytical technique is now available to rapidly analyze candidate SPM machine designs using concentrated windings and tune them to meet the critical condition for optimal flux weakening. This analtyical tool is used to demonstrate that optimal flux weakening can be achieved in SPM machines that are varied over wide ranges in several key dimensions including machine pole numbers, diameter-to-length aspect ratios, and output power ratings. Performance requirements for a 6kW direct-drive automotive starter/alternator machine are used as the starting point for the scalability investigation. Finite element analysis results are presented to confirm the validity of key results. A.M. El-Refaie, T.M. Jahns
2005-007 007 Impact of Inductor Placement on the Performance of Adjustable Speed Drives Under Input Voltage Unbalance and Sag Conditions IEEE 2005 International Electric Machines and Drives Conference, May 15-18 2005, San Antonio, TX, USA Voltage unbalance or sag conditions generated by the line excitation can cause the input rectifier stage of an adjustable-speed drive (ASD) to enter single-phase rectifier operation. This degradation of the input power quality can have a significant negative impact on the induction machine performance characteristics, but the presence of an LC filter in the drive’s input rectifier stage can be used to attenuate theseundesired effects. The purpose of this paper is to investigate the impact of the inductor placement in the ASD topology on the drive’s performance under voltage unbalance or sag conditions. More specifically, the relative advantages of choosing either a dc link choke inductor or three ac line inductors are discussed using a combination of closed-form analysis and simulations. Theresults of first-order sizing calculations show that a dc link choke inductor may offer some volume and mass advantages over three separate ac line inductors for the same ASD performance under unbalanced voltage conditions. Experimental results using a 5 hp ASD confirm the key analytical performance predictions. K. Lee, T.M. Jahns, D.W. Novotny, T.A. Lipo, W.E. Berkopec, V. Blasko
2005-008 008 Calculations of Motor Capacitances for Prediction of Discharge Bearing Currents in Machines of Inverter-Based Drive Systems" IEEE Transactions on Industrial Electronics (Impact Factor: 5.17). May 2007. bearings (mechanical), failure analysis, variable speed drives The occurrence of high frequency discharge bearing currents (also: “EDM-currents”) that can occur in machines of inverter-based drives systems depends strongly on the value of the capacitive voltage divider BVR (Bearing Voltage Ratio) of the machine. This paper presents a straightforward approach to calculate the involved motor capacitances in order to predict the occurrence of discharge bearing currents in inverter-based drive system. The approach is based on the design parameters of the machine and does not involve additional measurements. It combines ease of application and satisfying accurateness and allows prediction of the risk of endangerment of an inverterbased drive system due to discharge bearing currents. A. Muetze, A. Binder
2005-009 009 Calculation of the Influence of Insulated Bearings and Insulated Inner Bearing Seats on Circulating Bearing Currents in Machines of Inverter-Based Drive Systems IEEE Transactions on Industry Applications, (Volume:42 , Issue: 4 ). bearings (mechanical), failure analysis, variable speed drives The high frequency circulating bearing current that may occur in machines of inverter-based drive systems can be reduced or even completely suppressed by use of insulated bearings or insulated inner bearing seats. The influence of the thickness of the insulating coat can be calculated as a function of several machine design parameters. The parameters of the equivalent circuit are derived from an eddy-current model. The calculation considers the transient nature of the current flow. For motors up to 500 kW rated power, a minimum thickness of the insulating coat of 250µm is required to reduce the circulating bearing currents down to less than 30%. A. Muetze, A. Binder
2005-010 010 Towards a Global Optimization of Electromechanical Energy Converters via Exploitation of Convex Characteristics IEEE International Conference on Electric Machines and Drives, 2005. Electric machines, genetic algorithms, global optimization As the design requirements of electromechanical energy converters become increasingly complex, reliable and efficient optimization is seen as an important tool in the design process. However, general, comprehensive statements about the optimization of electromechanical energy converters, notably in regards to the verification of optimality and the best problem formulation are still missing at large. This concerns notably the issue of locally versus globally optimal solutions when using one of the many available codes for optimization of arbitrary nonlinear functions. The paper presents the mathematical reformulation of different problems of a magnetic circuit by exploitation of convex characteristics. This structure exploitation allows application of convex optimization that has proven to be not only a very efficient, but also a highly reliable optimization method. This step is considered as a key element for further optimization of a large variety of electromechanical energy converters. A. Muetze
2005-011 011 Operation and Control of a Dynamic Voltage Restorer Realized Using Cascaded H-Bridge Converters IEEE Power Electronics Specialists Conference (PESC). The dynamic voltage restorer as a means of series compensation for mitigating the effect of voltage sags has become established as a preferred approach for improving power quality at sensitive load locations. Meanwhile, the cascaded multilevel type of power converter topology has also become a workhorse topology in high power applications. This paper presents the detailed design of a closed loop regulator to maintain the load voltage within acceptable levels in a DVR using cascaded multilevel converters. The paper presents system operation and controller design approaches, verified using computer simulations and a laboratory scale experimental prototype. B. Wang, G. Venkataramanan
2005-012 012 Fast and Smooth Initial Position and Magnet Polarity Estimation of Salient and Near Zero Saliency PM Synchronous Machines IEEE International Electric Machines and Drives Conference (IEMDC), San Antonio, TX, May 2005, pp. 1037-10 A general solution for initial position and magnet polarity estimation on PM machines is presented. The technique is based on carrier frequency signal injection and proves to be fast, simple and parameter insensitive. It is applied to both salient and very low saliency PM synchronous machines of different power levels. An important step to understanding the implementation is to map the saliency and magnet polarity information as a function of rotor position. A state filter topology is proposed to ensure fast, smooth and robust convergence of the initial position and magnet polarity estimation for a SPMSM with an extremely low saliency ratio. Test results demonstrate consistent performance across different machine types. M.C. Harke, D. Raca, R.D. Lorenz
2005-013 013 Modeling of a Radial Permanent Magnet Motor with Trapezoidal Shaped Poles, IEMDC 05, San Antonio, May 15 - 18, 2005. S.M. Madani, T.A Lipo, C.E Nino, D. Lugo
2005-014 014 Real-Time Simulation of Matrix Converter Drives European Power Electronics Conference (EPE), Dresden Germany, September, 2005. Matrix converters, Real-Time Simulation, Hardware-In-the-Loop Simulation, Interpolation This paper describes a real-time simulator of matrix converter system. The simulated plant is a classical matrix converter with source, input filter and load. The simulator is based on RT-LAB real-time simulation platform that allows for easy model-to-target design from Simulink models. The simulator is designed to accept real IGBT/GTO/MOSFET firing pulses from high performance I/O thus permitting matrix converter controller testing in hardware-in-the-loop (HIL) simulation. The matrix converter model use interpolation methods to have variable-step-solver equivalent precision in the fixed time step scheme required by HIL applications. The paper shows the speed and accuracy of the simulator and highlights the special techniques necessary to simulate kHz-range inverters. C. Dufour, L. Wei, T.A. Lipo
2005-015 015 Techniques for Measurement of Parameters Related to Inverter-Induced Bearing Currents 40th IEEE IAS Annual Conference, Hong Kong, October 2-6, 2005, paper number IAS 38p5. variable speed drives, inverter-induced bearing currents, common mode voltage Inverter-induced high frequency bearing currents are a parasitic effect that can occur in variable-speed drive systems. While the physical cause-and-effect chains are understood, little has been known on appropriate quantitative assessment of the phenomena. This paper discusses reliable techniques for the measurement of the different parameters of importance for the bearing damage assessment, including their effects on the phenomena and measured quantities. A good understanding of these correlations allows custom-design, costeffective handling of the matter. A. Muetze, A. Binder
2005-016 016 Scaling Issues for Common Mode Chokes to Mitigate Ground Currents in Inverter-Based Drive Systems 40th IEEE IAS Annual Conference, Hong Kong, October 2-6, 2005, paper number IAS 5245. variable speed drives, common mode voltage, common mode current, converter-machine interactions The additional high frequency common mode current of inverter-based drive systems can cause parasitic effects such as high frequency bearing currents. This high frequency common mode current can be significantly reduced by purpose-designed common mode chokes that are inserted in the drive at the inverter-output. The paper discusses scaling issues related to the design of such common mode chokes, both of wound and feed-through toroidal types. The requirements for the design of chokes for these applications can differ from those for common mode chokes designed for use in the inverterinput, such as those used for the purpose of EMI filtering. This difference is notably due to the comparatively large magnitude of the currents involved. The developed correlations allow taking full advantage of the possibilities offered by such chokes to reduce the high-frequency common mode current and miti-gate the resultant parasitic effects. The discussed relationships are derived analytically, and the results are supported by measurements. A. Muetze
2005-017 017 Performance Evaluation of Electric Bicycles 40th IEEE IAS Annual Conference, Hong Kong, October 2-6, 2005, paper number IAS 80p4. power-assisted bicycle, direct drive, battery, efficiency, performance evaluation Electric motor powered bicycles (short: “electric bicycles”) have been making their way into the U.S. market for about two decades. Such electric bicycles can be used for a large variety of purposes. This paper gives a systematic, comprehensive, theoretically and experimentally based characterization of electric bicycles, and reports on the different performance requirements. Thereby, the needs and challenges in designing electric bicycles with improved overall performance are identified. For example, generally critical issues such as heavy, bulky batteries and high drive costs can be addressed. Furthermore, the overview can be used for comparison of existing drives in a thorough, technically meaningful way. A. Muetze, Y.C. Tan
2005-018 018 Influence of Teeth and Cooling Ducts on the HF Common Mode Flux of Inverter-Fed AC Machines 40th IEEE IAS Annual Conference, Hong Kong, October 2-6, 2005, paper number IAS 37p6. variable speed drives, common mode voltage, high-frequency common mode flux, finite element method, inverter-induced bearing currents Inverted-fed asynchronous machines suffer from high-frequent common mode current components generating circumferential fluxes in the stator, rising a voltage drop along the shaft and possibly leading to endangering circulating bearing currents. The common mode current distribution in the stator laminations can be described by a 2D axisymmetric eddycurrent model which, however, neglects azimuthal asymmetries such as stator slots. In this paper, this model is extended to better reflect the geometry of the laminations. Furthermore, a finite-element model incorporating all cross-sectional details is constructed. A comparison of the extended models to the original one indicates that stator slots and cooling ducts housing can significantly influence the magnitude of the common mode flux. A. Muetze, H. De Gersem, T. Weiland
2005-019 019 A Contribution to Identification of Convex Structures for Global Optimization of Permanent Magnet Machines 40th IEEE IAS Annual Conference, Hong Kong, October 2-6, 2005, paper number IAS 07p6. permanent magnet machines, genetic algorithms, global optimization Application of modern mathematical optimization has become an important tool for the design of permanent magnet machines. This paper focuses on identification of particular mathematical structures, which can be obtained by appropriate formulation of otherwise well-known analytical equations. This problem formulation can be used for reliable and efficient optimization, notably in regards to the certification of the optimality. In other words, locally optimal solutions are avoided, and it can be guaranteed that a solution is globally optimal. The tool for the certification of optimality is the exploitation of convexity characteristics during the problem formulation, as convex optimization has proven to be a very efficient and highly reliable optimization method. To this aim, the problem formulation for maximization of several performance parameters of a brushless DC permanent magnet motor with use of soft magnetic composites and 3D flux distribution is discussed. The results can be considered as elements of a library of tools leading towards reliable and efficient optimization of permanent magnet machines. A. Muetze
2005-020 020 Comparison of Synchronous PM Machine Types for Wide Constant-Power Speed Range Operation 2005 IEEE Industry Applications Society Annual Meeting, 2-6 October 2005, Hong Kong. flux weakening; synchronous machines; permanent magnet; surface; interior; concentrated; fractional-slot; windings. This paper presents a detailed comparison of the high-speed operating characteristics of four synchronous PM machines for applications that require wide speed ranges of constant-power operation. These machines include surface PM machines with both distributed and fractional-slot concentrated windings, and two interior PM machine with distributed windings. These two versions of the interior PM machine include one with and a tight constraint on the machine’s back-emf voltage at top speed and one without this constraint. The target application is an automotive direct-drive starter/alternator requiring a very wide 10:1 constant power speed ratio (CPSR). Detailed comparisons of the performance characteristics of the machines are presented that include important issues such as the back-emf voltage at top speed, machine mass and cost, and eddy current losses in the magnets. Analytical results are verified using finite element analysis (FEA). Guidelines are developed to help drive designers decide which type of machine is most suitable for high-CPSR applications. Tradeoffs associated with choosing each of these machines are presented. A.M. El-Refaie, T.M. Jahns
2005-021 021 Experimental Verification of Optimal Flux Weakening in Surface PM Machines Using Concentrated Windings 2005 IEEE Industry Applications Society Annual Meeting, 2-6 October 2005, Hong Kong. flux weakening; synchronous; permanent magnet;surface; concentrated; fractional-slot; windings; experimental; verification. Previous analytical work has shown that it is possible to design surface PM (SPM) machines using fractionalslot concentrated windings to achieve wide speed ranges of constant power operation by satisfying the optimal fluxweakening condition. This paper presents a 6kW 36-slot/30-pole concentrated winding prototype SPM machine that has been designed using a closed-form analytical technique developed specifically for this class of machines. Experimental testing of this machine has been carried out to determine its performance capabilities, including flux-weakening operation. Detailed comparisons between analytical, finite element analysis (FEA), and experimental results are presented that confirm the ability of fractional-slot concentrated winding SPM machines to achieve their high-speed operating objectives. Important issues including the machine’s back-emf voltage at top speed, eddy current losses in the magnets, and inverter performance are analyzed and discussed in detail. A.M. El-Refaie, T.M. Jahns, P.J. McCleer, J.W. McKeever
2005-022 022 Current Control for AC Motor Drives Using a Single DC Link Current Sensor and Measurement Voltage Vectors 2005 IEEE Industry Applications Society Annual Meeting, 2-6 October 2005, Hong Kong. Industry Applications, IEEE Transactions on. Volume 42, Issue 6, Nov.-dec. 2006 pp.1539-1547. dc link current sensor, measurement voltage vectors, current reconstruction, current regulation, virtual active resistance state feedback, dynamic stiffness A new algorithm using a single dc link current sensor to reconstruct all three inverter phase currents has been proposed that overcomes problems caused by the presence of regions in the voltage vector plane where the phase currents are not conveniently measurable. The measurement vector insertion method (MVIM) achieves this objective by applying additional active voltage vectors for brief intervals only when needed during each fundamental frequency cycle. This paper addresses techniques for incorporating the MVIM algorithm into a closedloop current regulator designed to provide high-quality current control using a single dc link current sensor. Virtual active resistance state feedback (VARSF) is introduced into the synchronous-frame current regulator in order to improve the controller’s ability to reject disturbances caused by the MVIM measurement vectors. Experimental results are provided to confirm the attractive performance characteristics of the resulting current reconstruction and regulation using the MVIM algorithm. H. Kim, T.M. Jahns
2005-023 023 Impact of Input Voltage Sag and Unbalance on DC Link Inductor and Capacitor Stress in Adjustable Speed Drives, 2005 IEEE Industry Applications Society Annual Meeting, 2-6 October 2005, Hong Kong. This paper investigates the impact of input voltage unbalance and sags on stresses in the dc bus choke inductor and dc bus electrolytic capacitors of adjustable-speed drives (ASDs). These stresses are primarily attributable to the rectifier’s transition into single-phase operation, giving rise to low-order harmonic voltages (120 Hz, 240 Hz, etc.) that are applied to the dc link filter components. These harmonics elevate the ac flux densities in the dc choke core material significantly above values experienced during normal balanced excitation conditions, causing additional core losses and potential magnetic saturation of the core. It is shown that the effects of voltage unbalances and sags on the dc link capacitor lifetime will be the same when either line inductors or a dc link choke inductor are used if the dc choke inductance value is twice the value of the line inductance. Simulations and experimental tests are used to verify the accuracy of predictions provided by closed-form analysis and simulation for a 5 hp ASD system. K. Lee, T.M. Jahns, T.A. Lipo, G. Venkataramanan, W.E. Berkopek
2005-024 024 Current Regulation for Surface Permanent Magnet Synchronous Motor Drives Using Integrated Current Sensors in the Low-Side Switches 2005 IEEE Industry Applications Society Annual Meeting, 2-6 October 2005, Hong Kong. Industry Applications, IEEE Transactions on. Volume 42, Issue 4, July-Aug. 2006, pp. 1080-1091. Integrated current sensor, pilot device, Surface Permanent Magnet Machine, synchronous frame current regulation. A new synchronous-frame current regulator configuration for surface PM machine is presented that utilizes incomplete phase current measurements from integrated pilot current sensors to deliver attractive regulator performance. Since pilot current sensors are directly integrated into the power switching devices, they provide opportunities to reduce the cost, size, and weight of three-phase inverters by eliminating dedicated current sensors in motor drive applications. However, a threephase inverter equipped with these sensors in the three low-side switches cannot measure the complete load current waveforms, requiring the development of this new current regulator algorithm. An auto-tuning method is described that significantly reduces the sensitivity of the regulator to errors in the estimated machine parameters. Experimental results are provided to verify the appealing performance characteristics of the proposed regulator. S. Chakrabarti, T.M. Jahns, R.D. Lorenz
2005-025 025 Generalized Averaged Dynamic Modeling of Vector Switching AC Power Flow Controllers IEEE Power Electronics Specialists Conference (PESC), June 12-16, 2005, Recife, Brazil. Various devices based on thyristor phase control technology such as the SVC, TCSC and dc link technology such as HVDC, STATCOM, SSSC, and UPFC have been proposed and applied for ac power flow control. Alternatively, ac link power flow control devices based on pulse width modulation technology have been proposed in various forms including phase angle control, series reactance control, back-back interties, etc. The objective of this paper is to develop low frequency dynamic models for these converters that enable their application for power flow control. The analytical development follows generalized averaging techniques in the phasor domain to develop a state space model that captures the low frequency response of the system. Due to nature of the excitation functions being ac, the classical state space averaging techniques are refined further to accommodate the multiple frequency-cross product terms introduced due to the switching process. Detailed analytical development along with computer simulation results verifying the models are presented in the paper. F Mancilla-David, G. Venkataramanan
2005-026 026 Unity Power Factor Control for Three-Phase Three-Level Rectifiers Without Current Sensors IEEE Transactions on Industry Applications, VOL. 43, NO. 5, Sept./Oct. 2007. Unity power factor; Vienna Rectifier; Phase angle control; Carrier based PWM; Three level rectifiers with reduced number of switches (such as the Vienna Rectifier) have been receiving wide interest in the past years to improve the input power quality of rectifier systems. In this paper, a new carrier-based pulse width modulation (PWM) control algorithm is proposed for such converters to eliminate the low frequency harmonics in the line current while achieving unity power factor at the rectifier input terminals. The operating constraints of the Vienna Rectifier with the carrier-based modulation strategy are examined carefully and the proposed control algorithm ensures that appropriate voltage/current directional constraints are met. A promising cost reduction opportunity can be seen with elimination of input current sensing to operate the Vienna Rectifier. The control algorithm is verified via Saber simulation and experimental results. B. Wang, Venkataramanan,
2005-027 027 Double Side Control of Wound Rotor Induction Machine for Wind Energy Application Employing Half Controlled Converters 2005 IEEE Industry Applications Society Annual Meeting, 2-6 October 2005, Hong Kong. wound rotor induction machine, wind generator, Super-synchronous generating mode, half controlled converter, reduced switch configuration. A double side converter fed wound rotor induction machine control for a wind energy application is proposed in this paper. In order to reduce the cost of a wind generator system, a new configuration using half controlled converters for both the stator and rotor circuit as well as for the line side is proposed. The proposed controller reduces the required KVA rating of both machine side and line side converters, improves the efficiency of the wind generator, helps operating over a wide speed range and supports near unity power factor interface with the grid. It is shown that the combined KVA rating of both the machine side converters are even less than that of the machine side converter for a conventional rotor side control configuration. Also, both stator and rotor side being connected to the grid through two power stages, the system will be least affected by the fault or disturbances in the gird. The proposed configuration is simulated for a 30kW wound rotor machine in SABER and the simulation results are presented. D. Panda, T.A. Lipo
2005-028 028 Phase Current Reconstruction for AC Motor Drives using a DC Link Single Current Sensor and Measurement Voltage Vectors PESC 2005 HK. Power Electronics, IEEE Transactions on. Volume 21, Issue 5, Sept. 2006 pp.1413-1419 Three-phase current measurement using only a single current sensor in the inverter dc link is appealing for ac motor drives because it minimizes the number of current sensors, thereby reducing sensor cost, weight, and volume. However, the basic dc link single current sensor technique poses special challenges because the duration of the active voltage vectors must be long enough to measure the dc link current reliably during every PWM switching interval. A new single current sensor algorithm for reconstructing the phase currents called the measurement vector insertion method (MVIM) is presented that overcomes this problem using active voltage vectors that are applied for brief measurement intervals only when needed during each fundamental frequency cycle. The insertion of measurement vectors makes it possible to reconstruct the output phase currents with minimum impact on the machine's performance and operating envelope. A combination of analytical and experimental results is provided to confirm that the MVIM algorithm offers attractive phase current reconstruction performance in comparison to alternative dc link single current sensor algorithms. H. Kim, T.M. Jahns
2005-029 029 Analysis of Surface Permanent Magnet Machines with Fractional-Slot Concentrated Windings, IEEE Transactions on Energy Conversion. A.M. El-Refaie, T.M. Jahns, D.W. Novotny
2005-030 030 Modular Permanent Magnet Machine Based on Soft Magnetic Composite International Conference on Electrical Machines and Systems (ICEMS) 2005, September 27-29, 2005, Nanjing, China.. Soft Magnetic Composite, Permanent Magnet (PM), Concentric Windings, Single Phase, Multiple Phase, Fault Tolerant With the improvement of soft magnetic composite (SMC) material, electric machine design is no longer limited to the traditional iron lamination technology. The single extrusion fabrication process of the SMC material simplifies construction of machine armature core. Moreover, the isotropic material property can be exploited for various machine structure design, compared with the 2D flux distribution of typical iron laminations. In this paper, a drive system based on a novel multi phase modular permanent magnet machine is proposed. The concentric winding structure simplifies the stator structure with the benefit of less end winding loss, which also offers the potential of fault tolerant capability. The performance of the drive system is analyzed and discussed with the simulation results provided. W. Ouyang, S. Huang, A. Good, T.A. Lipo
2005-031 031 Saliency Tracking-Based, Sensorless Control of AC Machines Using Structured Neural Networks IEEE IAS Conf., Oct. 2-6, 2005, Hong Kong. The focus of this paper is the use of structured neural networks for sensorless control of AC machines using the zero sequence carrier signal voltage. Structured neural networks allow effective compensation of saturation-induced saliencies as well as other secondary saliencies. In comparison with classical compensation methods, such as lookup tables, this technique has advantages such as physics-based structure (and thus is potentially insightful), general scalability, reduced size and complexity, and correspondingly reduced commissioning time. When compared with traditional neural network solutions, the structured neural networks are simpler, physically insightful, less computationally intensive and easier to train. All make the proposed method an improved implementation for sensorless drives. P. Garcia, F. Briz, D. Raca, R.D. Lorenz
2005-032 032 Using Low Resolution Position Sensors in Bumpless Position/Speed Estimation Methods for Low Cost PMSM Drives IEEE IAS Conf., Oct. 2-6, 2005, Hong Kong. sensorless control; self-sensing control; current reconstruction; observer-based control, permanent magnet synchronous machine control A bumpless position/speed estimation method which uses only a low-resolution position senor is presented for low cost permanent magnet machine (PMSM) drives. By integrating methods, i.e. using a speed reference for zero speed startup, a low resolution Hall sensor for low speed acceleration, and back-EMF for high speed operation, the rotor position can be estimated and controlled over the entire speed range. In order to achieve bumpless transitions, the three techniques are combined with a crossover function based on the speed reference. The proposed method can be used in applications with unpredictable variation in loads, such as horizontal drum washing machines. H. Kim, S. Yi, N. Kim, R.D. Lorenz
2005-033 033 Integrated Current Sensing for Power Electronic Modules using GMR Field Detectors EPE 2005, Sept. 13-15, 2005. Dresden, Germany. Giant Magnetoresistance, Point-Filed Detecting, Integrated Current Sensing, Power Module The latest developments in point field detection for integrated current sensing are discussed. The effects that the skin-effect has on bandwidth and accuracy are explored. Numerical calculations and experimental measurements are performed on conductors with rectangular cross-sections. Point field measurements are made using giant magnetoresistive (GMR) field detectors, and are compared with results from numerical analyses. Two-dimensional finite element models demonstrate the tradeoff between flat measurement bandwidth and field strength as a function of frequency. Optimization functions are used to determine the best placement of the field detector for use as a current sensor. E.R. Olson, R.D. Lorenz
2005-034 034 Implementation Issues for Fast Initial Position and Magnet Polarity Identification of PM Synchronous Machines with Near Zero Saliency EPE 2005, Sept. 13-15, 2005. Dresden, Germany. Self-sensing control, Sensorless control, Permanent magnet motor, Motion control, Signal processing This paper presents a significant discussion of implementation details of an enhanced fast initial position and magnet polarity estimation method for low saliency PM synchronous machines. The carrier frequency operating-point model of the machine has been extended to include the effect of cross-saturation as part of the non-linear interactions of the machine inductance to an applied rotating voltage vector. The resulting carrier signal current components are isolated using synchronous reference frame filtering and the initial position and magnet polarity is estimated using a dual-vector tracking state filter. The paper also provides an extended discussion of design tradeoffs in tuning of the synchronous reference frame filters in conjunction with the dual-vector tracking state filter bandwidth. Experimental results demonstrate fast, reliable initial position and magnet polarity estimation with improved accuracy and speed of convergence. M.C. Harke, D. Raca, R.D. Lorenz
2005-035 035 Dynamic Compensation of Torsional Oscillation in Paper Machine Sections, Proc. of IEEE IAS Pulp and Paper Industry Conf., Jun. 19-23, 2005, Jacksonville, Florida. pp. 81-89. Torsional oscillations, resonance, frequency response analysis, backlash, two mass modeling, torsional stiffness Torsional oscillations bound the speed loop bandwidth (BW) of industrial drives and servo systems, deteriorating the transient response to commands and to disturbances. This is especially harmful in multi-drive systems, like paper machines, that need to run synchronized. This paper presents two methods to dynamically compensate the torsional oscillations produced by the compliant components between the motor and the load: either a notch filter or acceleration feedback based on the rigid-body Luenberger observer. The evaluation includes the effect of the reducer backlash, whereby both time and frequency domain responses are used to compare the benefits of each technique in a typical paper machine section. Resultsshow that both methods, if properly tuned, are effective techniques to reduce torsional oscillations, and are robust to parameter variations. J. Bentley, M.A. Valenzuela, A. Villablanca, R.D Lorenz
2005-036 036 Web Inspection Using Gradient-Indexed Optics IEEE IAS Pulp and Paper Industry Conf., Jun. 19-23, 2005, Jacksonville, Florida. Web sensing, hybrid sensor, linear array, gradient index lens, machine vision system, gradient lens array Photoelectric sensors, used to inspect product and packaging attributes, are ubiquitous in manufacturing processes of today. Most common are single element sensors that detect the presence or absence of an attribute, product, or package as a binary on/off signal. In the web converting industry, more detailed information is often needed of the web than a single sensor can detect. In addition, single element sensors are often not sufficient to reliably sense product attributes. A small amount of contamination can render single element sensors dysfunctional. They are also hindered from being able to distinguish between components on products that respond similarly to the light source but may differ in geometric shape on the product. Machine vision systems can detect much more detail and have proven effective for many challenging applications. However, due to their complexity, they are generally specified only for the most challenging or most critical quality inspections. This paper will present a new, hybrid approach to product attribute sensing employing desirable aspects of both single element sensors and machine vision systems without many of the disadvantages of each. The hybrid sensor contains a linear array of pixel elements along with agradient-indexed lens array. The linear array allows for greater sampling and geometric characterization in one dimension while the lens array allows for very close standoff distances from the web and a 1:1 correspondence of object to image. The presentation of this sensor technology includes a tutorial on the key technical properties of gradient-indexed optics and experimental results on a composite web running on a trial machine. J.H. Sorebo, R.D. Lorenz
2005-037 037 Key Technologies for Future Motor Drives Proc. of ICEMS Conference 2005, Sept. 27-29, 2005. Nanjing, China. This paper presents technologies that have strategic importance in future motor drives. The underlying strategic issue for motor drives is maintaining cost while increasing certain dimensions of functionality. The dimensions of functionality which should increase include reliability and added value features such as providing continuous energy optimization, providing sensing of the driven system suitable for application specific diagnostic purposes, and providing continuously optimal thermal utilization of the capability of the drive. This paper will address each of these issues and discuss the technology status for each case, with a focus on research needed to fully deliver the needed functionality. R.D Lorenz
2005-038 038 Generalized Steady-state Analysis of Multiphase Interleaved Boost Converter with Coupled Inductors IEEE Proc.-Electr. Power Appl., Vol. 152, No. 3, May 2005 The generalised steady-state analysis of the multi-phase interleaved boost converter with coupled inductors operated in continuous inductor current mode is addressed. The analytical expressions for efficiency, inductor and input currents, and output voltage are derived from the transformed average state–space model. Generalised expressionsfor the input and inductor current ripples and the output voltage ripple are also derived for various inductor couplings and the characteristics are analysed according to the inductor couplings. The steady-state performance is verified experimentally. H.B. Shin, J.G. Park, S.K. Chung, H.W. Lee, T.A. Lipo
2005-039 039 An Electrodynamic Wheel with a Split-Guideway Capable of Simultaneously Creating Suspension, Thrust and Guidance Forces 8th International Symposium on Magnetic Suspension Technology, September 2005, Dresden, Germany. electrodynamic, guidance, Halbach array, maglev, propulsion, suspension When a radially positioned permanent magnet Halbach array is rotated above a flat aluminium guideway a travelling time-varying magnetic field is created in the air-gap. The field induces currents in the guideway that simultaneously creates a suspension and propulsion force. With a suitably designed guideway the ‘Electrodynamic Wheel’ (EDW) can also create guidance forces. A split-guideway ladder topology is analyzed using a 3D analytic model of the Halbach rotor with a dynamic lumped parameter model of the guideway developed in Matlab. The forces within the airgap are calculated using Maxwell’s stress tensors. The Matlab model is comparing with a transient finite element Magsoft Flux 3D model. J. Bird, A. Lipo
2005-040 040 A Study of the Effect of Using Electrodynamic Wheels in Series 8th International Symposium on Magnetic Suspension Technology, September 2005, Dresden, Germany. maglev, electrodynamic, suspension, propulsion, Halbach array The mechanical rotation of a radially positioned permanent magnet Halbach array above a conducting, non-magnetic, track generates a travelling time-varying field that can inductively create suspension and propulsion forces simultaneously. This ‘Electrodynamic Wheel’(EDW) could be used to create a relatively cheap form of maglev transportation since the track would only consist of thin sheets of aluminum and no track electrification is necessary. The effect of using multiple EDW’s in series is studied by using 2D steady-state finite element analysis. It is shown that the thrust efficiency can be considerably improved by increasing the number of EDW's used in series. A comparison is made between an EDW driven maglev vehicle and other maglev vehicle systems. J. Bird, T.A. Lipo
2005-041 041 A New Polyphase Matrix Converter Topology IECON conference, 31st Annual Conference of the IEEE Industrial Electronics Society, Nov 6-10. A new topology for bidirectional sinusoidal ACAC power conversion is proposed in this paper. The power converter topology is derived from conventional three phasethree phase matrix converters. Theapproach uses polyphase balanced three phase AC voltage stiff sources interfaced to three phase current stiff loads using a switching matrix. Availability of isolated balanced three phase ac sources allows the use of reduced number of switches with two quadrant switches, thereby allowing a simple realization of the converter. A set of phase shifting transformers is used to generate polyphase voltages sets to drive the converter. An analysis of the semiconductor and transformer VA rating is presented. A switch modulation technique is developed using vector representation of the converter input-output properties. Experimental results from a laboratory prototype converter are presented to verify the operation of the converter. P.S. Flannery, G. Venkataramanan
2005-042 042 A Decentralized Protection Scheme for Converters Utilizing a DC-link Inducto IECON Conference, 31st Annual Conference of the IEEE Industrial Electronics Society, Nov 6-10, 2005 This paper proposes a fully passive protection scheme for DC link inductors whose geometry is characterized by a substantial distance between the rectifier and inverter stations. Inductors of this type can be found intrinsically in very long high-power cables - as in HVDC transmission for example – as well as in DC-links for high-power current source inverters. In such applications the inductor must be duly protected against overvoltages as well as against overcurrents potentially occurring as consequence of an open-circuit or a short-circuit fault respectively. The distance between the inductor terminals prevents the use of well-known localized protections like, for example, simple freewheeling diodes. A key role in the protection scheme proposed by the authors is played by the largely available transient suppressor diodes (often commercially identified as “Tranzorbs”) and the solution is kept very simple and reliable by employing only rugged diodes and thyristors. The protection relies only on the energy stored in the inductor without the need of any external supervision circuit or any information exchange between the distant inductor terminals. Experimental results are presented and a generalization of the scheme to a broader application is also introduced. P. Tenca, T.A. Lipo
2005-043 043 The Neutral Point Clamped Resonant DC Link Converter – A new three level soft switched topology IEMDC multi-level; inverters; neutral point clamped; resonant dc link; sigma delta modulator A new topology, the neutral point clamped resonant dc link inverter (NPC-RDCLI) that extends the benefits of the resonant dc link to NPC converters is presented. Three level or neutral point clamped converters (NPC) are typically operated at medium voltage using either integrated gate commutated thyristor (IGCT) or high voltage insulated gate bipolar transistor (HV-IGBT) devices. These high di/dt turn-off devices coupled with inherent parasitic inductances in the NPC pole structure produce large diode recovery transients for certain commutation sequences that compromise the device voltage margin. The NPC-RDCL achieves zero voltage switching of the all devices and minimizes recovery transients via low di/dt turnoff of pole diodes that significantly reduces commutation voltage overshoots and increases device utilization. The paper includes a detailed explanation of the circuit operating modes, commutation modes, multilevel sigma delta modulator, nearest neighbor three level vector quantizer and simulation results. I. Wallace, A. Bendre, G. Venkataramanan
2006-001 001 Matrix Converter BLDC Drive using Reverse-Blocking IGBTs IEEE Applied Power Electronics Conference Proceedings, (Dallas, TX, USA), Mar. 2006. This paper demonstrates a method of using a matrix converter with reverse blocking IGBTs (RB-IGBTs) to drive a brushless DC (BLDC) motor with non-sinusoidal flux distribution. The output currents are nearly rectangular and the input currents are sinusoidal. Recently introduced RB-IGBT modules allow for an efficient implementation of the classical topology 18-switch matrix converter. The RB-IGBT modules are controlled so as to provide the required freewheeling paths for the motor currents. The paper presents a suitable carrier-based modulation strategy along with a discussion of selected design issues. Computer simulation and preliminary experimental results are presented. Major advantages and disadvantages of the system are discussed. S. Bala, G. Venkataramanan
2006-002 002 Using the Dynamic Behavior of Superimposed Fields for Point Field-Based Current Sensing IEEE Applied Power Electronics Conference Proceedings, (Dallas, TX, USA), Mar. 2006. The dynamic behavior of magnetic fields surrounding adjacent current carrying conductors is investigated for the purpose of point field-based current sensing. The influence of eddy currents on magnetic field distribution over the useful spectrum (DC to 1 MHz) is quantified using a spatially dependent metric, the 5% Flat Bandwidth (FBW). A comparison of field distributions at DC and 1 MHz show the origin of the FBW function, which is unique to each conductor’s cross-section and nearby environment. The FBW fields for several different conductor geometries are analyzed. Superposition is used for conductor geometries that have multiple currents. A method for determining optimal field detector placement using optimization functions is introduced. E.R. Olson, R.D. Lorenz
2006-003 003 2006-1309: A Project Experience in Power Engineering Design Aspects 113th Annual Conference & Exposition of the American Society for Engineering Education, June 20-6, Chicago, IL. G. Venkataramanan, A. Muetze
2006-004 004 2006-1312: Features of a Constructivist Microclimate Situated in a Behaviorist Learning Environment at a University-Based Engineering Research Consortium 113th Annual Conference & Exposition of the American Society for Engineering Education, June 20-6, Chicago, IL. G. Venkataramanan, A. Muetze
2006-005 005 Analytical Modeling of Semiconductor Losses in Matrix Converters 5th International Power Electronics and Motion Control Conference, Shanghai, China, Aug. 13-16, 2006 conduction loss; conventional matrix converter (CMC); indirect matrix converter (IMC); simulation; switching loss; Analytical models for estimating semiconductor losses are commonly used for heatsink selection in the design process of power converters. While such models are established and widely known for different dc-dc converters, rectifiers and inverters, they have not been developed for matrix converters. Therefore, one has to resort to the use of numerical simulation for this purpose. Although numerical simulation is a straightforward approach as long as the power switching devices are properly modeled, it is typically time consuming and requires accurate physical models for the device. In this paper, an analytical approach to characterizing the semiconductor losses of the conventional matrix converter (CMC) and the indirect matrix converter (IMC) is presented. The analytical results are verified against the simulation results from a detailed numerical model under a wide variety of operating conditions. B. Wang, G. Venkataramanan
2006-006 006 A Carrier Based PWM Algorithm for Indirect Matrix Converters 37th Power Electronics Specialists Conference, Jeju, Korea, June 18-22, 2006. In this paper, the indirect matrix converter is systematically studied with the single-pole-multiple-pole representation. A carrier based PWM algorithm is developed in two steps. First, the continuous modulation functions for all the throws are derived based on the desired sinusoidal input currents. Then the switching functions are derived from the modulation functions with focus on the zero current commutation. The proposed PWM algorithm is verified by numerical simulation and hardware experimentation on a laboratory prototype matrix converter. B. Wang, G. Venkataramanan
2006-007 007 Six Step Modulation of Matrix Converter with Increased Voltage Transfer Ratio 37th Power Electronics Specialists Conference, Jeju, Korea, June 18-22, 2006. Conventional modulation strategies for matrix converters based on trigonometric transformations and space vector techniques have their voltage transfer capability limited at about 0.866 p.u. This leads to a derating of motor capability by 25% in the realization of variable frequency drives using off-the-shelf line-fed motors, or requires custom designed motors for operation at reduced voltage. In this paper, a sixstep variable frequency modulation strategy for the matrix converter that is capable of providing more than 1 p.u. fundamental component of output voltage is presented. Six step operation suitable for the conventional 9-switch topology and the reduced switch dual bridge topologies are presented, with capability of unity displacement factor operation at the input and output simultaneously. It is demonstrated that by varying the switching angles, control of fundamental component of output voltage and input current is possible, with concomitant generation of reactive power at the input and output terminals of the converter, with bidirectional power flow. The paper presents analytical results, computer simulation results along with laboratory scale experimental results. B. Wang, G. Venkataramanan
2006-008 008 Robust Magnet Polarity Estimation for Initialization of PM Synchronous Machines with Near Zero Saliency 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. initial position estimation, self-sensing, sensorless, PM machines This paper investigates magnet polarity estimation of permanent magnet synchronous machines. Because the magnet polarity is estimated from low signal-to-noise ratio signals, it is sensitive to additional signal content, affecting the robustness of magnet polarity estimate. An evaluation of eight low saliency machines identifies a dc-offset vector in the positive 2nd harmonic carrier signal current as the primary source of magnet polarity estimation error. Angular offset is a secondary limitation to the polarity estimation robustness. By estimating and decoupling the dc-offset vector and the angular offset the robustness is improved and applicability to a wide set of the machines is enabled. D. Raca, M.C. Harke, R.D. Lorenz
2006-009 009 Reduction of Bearing Currents in Doubly Fed Induction Generators 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. Bearing currents have been identified as a major cause of electrical machine failure when operating from a solid-state pulse-width modulated inverter. This is because at frequencies corresponding to the switching time of the inverter semiconductors, charges accumulating in the parasitic capacitances between the stator and rotor create voltages across the bearings of the machine that eventually discharge and damage the bearings. It is to be anticipated that generators as well as motors would be susceptible to bearing failure in this way, particularly in wind turbine applications where a frequency converter is often used to convert the power produced by the variable speed turbine to AC electrical power at a constant line frequency. This paper presents a novel approach to reducing bearing currents in doubly fed operation wound rotor induction machines where the rotor is controlled by a back-to-back rectifier/ inverter system. The approach used is to constrain the inverter PWM strategy to reduce overall common mode voltages across the rectifier/inverter system, and thus significantly reduce bearing discharge currents. It is shown that the common mode voltage can be almost completely eliminated, at the price of a reduction in voltage gain of the rotor supply to 57% of the supply voltage. However, since the wind generator is never required to operate at more than plus or minus 30% above or below synchronous speed. This limitation is of little consequence in variable speed wind turbine applications. A.M. Garcia, D.G. Holmes, T.A. Lipo
2006-010 010 Current-Source Topology for Wind Turbines Capable of Providing Leading Power Factor While Reducing Line Current Harmonics 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. IEEE Transactions on Industry Applications. Axial Flux Permanent Magnet Generator, Current-Source Topology, Harmonics Reduction, Power Factor Control, VAR compensation, Wind Turbines The paper presents a Current-Source Inverter topology conceived for multi-megawatt wind turbines. The proposed scheme utilizes two series-connected three-phase inverters employing fully controllable switches and a proper interconnection transformer with the Mains. In order to improve the efficiency and allow the use of high power devices, the inverters are switched at mains frequency. The axial flux permanent magnet generator is directly coupled to the turbine (gearless solution) and possesses very low leakage inductance. The overall control technique allows to impose independently two desired quantities selected out of the set of three composed by: a) The total average voltage at the DC input side of the inverters; b) The power factor at the Mains interconnection point, which can be chosen unitary leading or lagging; c) The amount of the 5th and 7th harmonics in the Mains line currents. In specific operating points of the turbine a significant reduction of two such harmonics can be already achieved without additional filters and/or active harmonic compensation. Nevertheless the introduction of an active harmonic compensator can achieve proper harmonic reduction - also up to higher orders - more independently and on a wider range of operating conditions. Experimental results, obtained from a 10 kW prototype with an axial flux permanent magnet generator are presented. P. Tenca, A.A. Rockhill, T.A. Lipo
2006-011 011 Permanent Magnet Machine Design Practice and Optimization 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. Permanent Magnet, Design Optimization, FEA, Differential Evolution (DE) The complexity of the permanent magnet (PM) machine structure makes the optimal design of the PM machine always a difficult task. The multiple objectives of an optimal design make most classic optimization algorithms inapplicable, due to the nonlinearity and some discontinous variables. In this paper, two interior permanent magnet (IPM) machine design practices with modular stator structure and conventional stator structure are discussed. The design process is directly coupled with finite-element analysis (FEA) with the machine design guidelines embedded in the optimization process. Multivariable optimization methods based on Monte Carlo and Differential Evolution algorithms are applied in the design phase and the results are compared in this paper. W. Ouyang, D. Zarko, T.A. Lipo
2006-012 012 A Grid Fault Tolerant Doubly Fed Induction Generator Wind Turbine via Series Connected Grid Side Converter American Wind Energy Association (AWEA) WINDPOWER 2006 Conference, June 4-7, 2006, Pittsburgh, PA. With steadily increasing wind turbine penetration, regulatory standards for grid interconnection are evolving to require that wind generation systems ride-through disturbances such as faults and support the grid during such events. Conventional modifications to the doubly fed induction generation (DFIG) architecture for low voltage ride-through result in limited control of the turbine shaft and grid current during fault events. A new electrical architecture for DFIG wind turbines with improved low voltage ride-through is explored. The proposed approach employs a back-to-back AC/DC/AC power electronic converter chain in which the grid side converter is connected in series with the DFIG stator windings, as opposed to parallel in the conventional case. The machine side converter is fed from the rotor windings of the DFIG, as in the conventional DFIG. Series connection of the grid side converter enables voltage sag ride-through capability via control of the stator flux. In the event of a grid voltage sag, the series converter allows for a controlled response in the stator flux and electromagnetic shaft torque, protects the machine side converter and enables continued power delivery to the grid. Steady state operating conditions are investigated to develop an understanding of the power processing capabilities of the DFIG with only series grid side converter. Limitations of the series grid side converter power processing capabilities motivate the introduction of two unified DFIG architectures employing both series and parallel grid side converters. P. Flannery, G. Venkataramanan
2006-013 013 Design and Experimental Verification of a 50 kW Interior Permanent Magnet Synchronous Machine 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. Interior permanent magnet (IPM) synchronous motor; constant power speed ratio (CPSR); flux weakening; design optimization; cross-saturation; iron losses; prototype machine This paper presents the design details for an IPM machine designed to deliver 50 kW constant power over a 5:1 speed range extending from 850 rpm to 4250 rpm, with a gradual reduction in the required output power up to 8000 rpm (25 kW). Electromagnetic, thermal, and structural considerations have been included in the design optimization process. The resulting machine is designed with two magnet layers per pole and a distributed stator winding. Special features of the machine include its deep stator slots and four-layer winding, made necessary by the desire to minimize the machine’s moment of inertia. Test results available to date demonstrate that the machine is capable of delivering the required output torque and power, and the agreement between the predicted and measured machine parameters is generally quite good. Calculated iron losses for high-speed flux-weakening operation are presented in the final section of the paper, illustrating the challenges associated with minimizing the impact of high-frequency harmonic flux density components. T.M. Jahns, S.H. Han, A.M. El-Refaie, J.H. Baek, M. Aydin, M.K. Guven, W. Soong
2006-014 014 Integration of the Measurement Vector Insertion Method (MVIM) with Discontinuous PWM for Enhanced Single Current Sensor Operation 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. dc link current sensor; measurement voltage vectors; discontinuous PWM, current reconstruction The previously-introduced Measurement Vector Insertion Method (MVIM) is a promising technique for providing three-phase current measurements using a single dc-link current sensor. If MVIM is combined with discontinuous PWM (DPWM), the number of added switching events can be significantly reduced. Additional advantages include a reduction of the unmeasurable regions by as much as 50%, and improved modulator linearity in the overmodulation region. A hybrid strategy that uses DWPM in the high-modulation-index region and conventional continuous SVPWM for all lower values of modulation index is proposed in order to maximize the advantages of the DPWM algorithm while minimizing its limitations. A combination of analysis, simulation, and experimental tests is used to demonstrate the attractive performance characteristics of the proposed MVIM enhancement technique. H.R. Kim, T.M. Jahns
2006-015 015 Modified Vector Control Algorithm for Increasing Partial-Load Efficiency of Fractional-Slot Concentrated Winding Surface PM Machines 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. concentrated windings; fractional-slot windings; flux weakening; partial-load efficiency; permanent magnet synchronous machine; surface PM motor; vector control. This paper presents a modified vector control algorithm for a fractional-slot concentrated-winding surface PM machine that has been developed to maximize the machine’s partial-load efficiency over a wide range of operating conditions. By increasing the amplitude of the negative d-axis current, the resulting increase in the stator copper losses can be more than offset by the reduction in the iron core losses achieved by lowering the stator d-axis flux amplitude. The effectiveness of this technique has been demonstrated using both analytical models and finite element analysis (FEA) for a 55 kW (peak) surface PM machine design developed for a demanding set of traction drive performance requirements. For this example, the modified control strategy increases the partial-load efficiency at 20% of rated torque by >6% at 2000 rpm compared to the maximum torque/Amp algorithm, making the machine much more attractive for its intended application. A.M. El-Refaie, T.M. Jahns, J. McKeever
2006-016 016 Impact of Winding Layer Number and Magnet Type on Synchronous Surface PM Machines Designed for Wide Constant-Power Speed Range Operation 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL flux weakening; synchronous machines; permanent magnet; surface; interior; concentrated; fractional-slot; windings. This paper thoroughly investigates the impact of the winding layer number and the choice of magnet type on the performance characteristics of surface permanent magnet (SPM) machines with fractional-slot concentrated windings designed for wide speed ranges of constant-power operation. This is accomplished by carefully examining the performance characteristics of three different SPM machines designed for the same set of performance requirements drawn from an automotive direct-drive starter/alternator application. These results show that double-layer stator windings yield lower torque ripple and magnet eddy-current losses than single-layer windings, but can contribute to a lower overload torque capability. Although the adoption of sintered magnets leads to the highest machine torque density, bonded magnets result in a significant reduction of the magnet losses because of their much higher value of resistivity. A.M. El-Refaie, T.M. Jahns
2006-017 017 Impact of Maximum Back-EMF Limits on the Performance Characteristics of Interior Permanent Magnet Synchronous Machines 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. interior permanent magnet synchronous machine; IPM, uncontrolled generator faults; UCG; back-emf limit Interior permanent magnet (IPM) synchronous machines are vulnerable to uncontrolled generator (UCG) faults at high speed that can damage the inverter. One approach to reducing this risk is to impose limits on the maximum machine back-emf voltage at top speed. This paper presents the results of a comparative design study that clarifies the nature and extent of the penalties imposed on the IPM machine metrics and performance characteristics as a result of imposing progressively tighter values of back-emf voltage limits. As an alternative to limiting back-emf and penalizing machine designs, this paper also investigates the effectiveness of the system-side protection approach to the same UCG fault problem. S. Han, T.M. Jahns, M. Guven, M. Aydin, W. Soong
2006-018 018 Disturbance Torque and Motion State Estimation Using Low Resolution Position Interfaces 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. Observers, position estimation, velocity estimation, torque estimation, spatial harmonics, quantization This paper assesses and analyzes a harmonic vector modeling method for reducing disturbance torque and motion state estimation error using quantized input measurements of position. There is a finite resolution available for any digital interface and quantization will always be present in some form. Although not possible to completely reconstruct a quantized measured state, it is possible to attenuate deterministic quantization characteristics. The discussed method models quantized position feedback as a spatially rotating vector consisting of fundamental and harmonic components. The error mitigation strategy involves decoupling these spatial quantization harmonics from the actual fundamental position, using heterodyning tracking observer topologies. T.R. Tesch, R.D. Lorenz
2006-019 019 Improved Coordinated Response and Disturbance Rejection in the Wet-End of Paper Machines IAS Pulp & Paper Industry Conf., June 18-23, 2006, Appleton, WI, pp. 111-123. Paper machine drive, disturbance rejection, 2-dof controller, disturbance observer, torsional oscillations. Critical sections of paper machines like presses, size presses, on-machine coaters and reels are required to undergo through eventually large and fast load changes, while maintaining the ingoing sheet tension as constant as possible to avoid wrinkling or breaks. This paper evaluates two disturbance rejection control techniques, one using disturbance feedforward (or disturbance input decoupling) based on a nip pressure disturbance observer, and the other using a 2-dof controller. Evaluations were done in both a press section and a size press section of lightweight paper machines and results showed that both methods are very effective reducing the maximum speed deviation to about 10% of the values without compensation, and that can operate combined with torsional oscillation compensation without interference between them. M.A. Valenzuela, J.M. Bentley, P.C. Aguilera, R.D. Lorenz
2006-020 020 Implementation Issues and Performance Evaluation of Surface-Mounted PM Machine Drives with Hall-Effect Position Sensors and Vector Tracking Observer 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. Hall effect sensors, vector-tracking observer, PM machine drive This paper presents the implementation of the Hall-effect sensor-based, vector-tracking observer and discusses its performance when used in an ac brushless drive for surface-mounted PM machines. First, the tuning of the observer is presented. Then, decoupling is used to improve the performance of the observer. Various decoupling strategies are investigated. Stability analysis is also carried out that leads to a maximum amount of position estimation error for the observer to track properly. This paper also demonstrates the benefits of harmonic decoupling with respect to position estimation and disturbance rejection. Both simulation and experimental testing are used to illustrate the performance and limits of the proposed observer topology and of the drive when this observer is used for state feedback. M.C. Harke, G. De Donato, F. Giulii Capponi, T.R. Tesch, R.D. Lorenz
2006-021 021 Dynamic Properties of Back-emf Based Sensorless PM Drives 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. sensorless drives; PM machines; speed estimation This paper investigates the speed sensitivity of backemf based sensorless techniques for PM machines. The eigenvalues of the back-emf based estimation are speed dependent leading to performance degradation including reduced command tracking and disturbance rejection. At low speeds, it is shown that instability will occur. The paper analyzes an operating point model of the permanent magnet synchronous machine for both sensor- and sensorless-based torque and position/velocity control. The sensorless techniques investigated include state filter-based and zero phase-lag observer-based approaches. In order to maintain disturbance rejection, the sensorless drives must operate at speeds significantly higher than the stability limit. L.A.S. Ribeiro, M.C. Harke, R.D. Lorenz
2006-022 022 Future Motor Drive Technology Issues and Their Evolution Invited Keynote paper, EPE PEMC Conf., Aug. 30-Sept. 1, 2006, Portoroz, Slovenia This paper presents technologies that have strategic importance for the evolution of future motor drives. The underlying strategic issue for motor drives is increasing high value-added functionality without adding cost. The high value-added functionality should include reliability in the presence of unknown loading, continuous energy loss minimization, integrated sensing suitable for application specific diagnostics, and continuously optimized thermal utilization of full drive capacity. This paper will address each of these issues and discuss the technology status for each case, with a focus on research needed to evolve the needed functionality. R.D. Lorenz
2006-023 023 Effect of Back-EMF Constraints on Fractional-Slot Surface PM Machines Designed for Wide Constant-Power Speed Range Operation 2006 International Conference on Electrical Machines (ICEM'06), Sept. 2-5, 2006, Chania, Greece back-emf, concentrated winding, flux weakening, fractional-slot, surface permanent magnet synchronous machine, SPM. This paper investigates the tradeoffs that result from constraining the back-emf at maximum speed for fractional-slot surface permanent magnet (SPM) machines. Two 55 kW (peak) SPM machines designed to meet requirements established in the US FreedomCar program are used as the basis for this investigation. The two machines are 36slot/30pole SPM fractional-slot concentrated-winding designs that use sintered NdFeB magnets. The first design has no back-emf constraint at maximum speed, allowing it to exceed the 600 V pk l-l limit, while the second design has been designed to meet this requirement. Results of this study show that the introduction of back-emf limits can lead to significant increases in the SPM machine’s rated current, with only a modest impact on the machines mass and volume. A combination of closed-form analysis and finite element analysis is used to carry out this investigation. A.M. El-Refaie, T.M. Jahns, J.W. McKeever,
2006-024 024 Comparison of Synchronous PM Machine Types for Wide Constant-Power Speed Operation: Converter Performance IET Electr. Power Appl., 2007, 1, (2), pp. 217-222. comparison, concentrated windings, distributed windings, converter, flux weakening, fractional-slot, interior PM, permanent magnet (PM), surface PM, synchronous machine. This paper presents a thorough comparison of the converter performance characteristics for four permanent magnet (PM) synchronous machine configurations. Two versions of an interior PM (IPM) machine with distributed windings are included. One version has a maximum back-emf limit at the top speed while the second does not have any constraint on back-emf amplitude. Two types of surface PM (SPM) machines are also considered, one with fractional-slot concentrated windings, and another with conventional distributed windings. The target application is an automotive direct-drive starter/alternator requiring a very wide 10:1 constant power speed ratio (CPSR). Detailed comparisons of the converter performance below and above the base speed are presented, evaluating significant issues including the converter switching and conduction losses, output ripple current, and dc link current ripple. Study results show that the higher excitation frequencies required by PM machines with high pole numbers have only a modest impact on converter efficiency for comparable output current waveform quality. In constrast, the imposition of maximum back-emf amplitude constraints at top speed raise the machine rated current, resulting in elevated converter losses and larger dc link capacitors. A.M. El-Refaie, T.M. Jahns
2006-025 025 Extraction of Temperature Information from Parallel Boost DC/DC Converters International Conference on Electrical Machines and Systems (ICEMS/), November 20-23, 2006, Nagasaki, Japan. junction temperature estimation, junction temperature control, MOSFET temperature, parallel converter load sharing. This paper proposes a novel method to extract temperature information from the ringing waveform of the converter. The lightly damped natural transient decay envelope that intrinsically occurs at switch turn-on is shown to depend on the on-resistance of the switch. Because the on-resistance of the switch depends heavily on temperature, the temperature information can be extracted from the ringing waveform. Methods to isolate the turn-on ringing in a boost converter and to acquire the temperature information from that signal is presented. The ringing waveform also appears naturally on the bus, which makes the bus become a intrinsic communication channel. The methodology is shown via experiments to eliminate the need for traditional temperature sensors and temperature signal communication hardware. M.L. Walters, J.L. Barnette, A. Nahar, M.R. Zolghadri, A. Homaifar, R.D. Lorenz
2006-026 026 Autonomous Control of Microgrids IEEE PES Meeting, June 2006, Montreal, Canada. CHP, distributed generation, intentional islanding, inverters, microgrid, power vs. frequency droop, voltage droop, Application of individual distributed generators can cause as many problems as it may solve. A better way to realize the emerging potential of distributed generation is to take a system approach which views generation and associated loads as a subsystem or a “microgrid”. The sources can operate in parallel to the grid or can operate in island, providing UPS services. The system will disconnect from the utility during large events (i.e. faults, voltage collapses), but may also intentionally disconnect when the quality of power from the grid falls below certain standards. Utilization of waste heat from the sources will increase total efficiency, making the project more financially attractive. Laboratory verification of the Consortium for Electric Reliability Technology Solutions (CERTS) microgrid control concepts are included. P. Piagi, R.H. Lasseter
2006-027 027 Dynamic Distribution using (DER) Distributed Energy Resources 2006 IEEE PES T & D Meeting, May 2006, Dallas, TX (Panel on Rethinking T&D Architecture for a DER Environment). R.H. Lasseter
2006-028 028 Microgrids and Distributed Generation Journal of Energy Engineering, American Society of Civil Engineers, 2006. Grid systems; Electric power supply; Powerplants. Application of individual distributed generators can cause as many problems as it may solve. A better way to realize the emerging potential of distributed generation is to take a system approach which views generation and associated loads as a subsystem or a “microgrid.” The sources can operate in parallel to the grid or can operate in island, providing utility power station services. The system will disconnect from the utility during large events e.g., faults and voltage collapses , but may also intentionally disconnect when the quality of power from the grid falls below certain standards. Utilization of waste heat from the sources will increase total efficiency, making the project more financially attractive. University of Wisconsin laboratory verification of microgrid control concepts are included. R.H. Lasseter
2006-029 029 Ocean Wave Energy Conversion - A Survey 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. ocean renewable energy, wave energy conversion Ocean energy conversion has been of interest for many years. Recent developments such as concern over global warming have renewed interest in the topic. This paper gives a systematic and comprehensive overview of wave energy converters (WEC) as opposed to ocean current energy converters. The point absorber and oscillating water column WEC devices are addressed with regards to commercial prospects, environmental concerns, current state-of-the art, and further research areas. Thereby, the paper seeks to enhance investigation of results obtained in other fields in the ocean wave energy conversion setting and to stimulate research on topics that have not been in the focus so far. A. Muetze, J.G. Vining
2006-030 030 Simplified Design of Common-Mode Chokes for Reduction of Motor Ground Currents in Inverter Drives 2006 IAS Annual Conference. Oct 8-12, 2006, Tampa, FL. A simpli?ed design calculation for common-mode chokes for reducing motor ground currents provides insight on the effects of various parameters and allows easy design. Key simplifying assumptions are that the voltage rise time is short compared to the ring period and that the damping is small. Example designs for machines up to 450mm frame size show how effective groundcurrent reduction is possible with small, inexpensive, single-turn chokes. A. Muetze, C.R. Sullivan
2007-001 001 The Spatial Effect and Compensation of Current Sensor Gain Deviation for Three-phase Three-wire Systems APEC 2007, 2/25 - 3/1/2007, Anaheim, CA. Current sensor errors affect torque control and saliency-tracking position estimation of ac machines. A spatial model of current sensor gain deviation is developed and used to determine its affect on a general current measurement, verified with experimental data. Three current sensors enable a threephase three-wire system to compensate for current sensor gain deviation independent of additional machine saliencies. Simulation and experimental results confirm the current sensor gain deviation compensation algorithm. M.C. Harke, R.D. Lorenz
2007-002 002 A Unified Architecture for Doubly Fed Induction Generator Wind Turbines using a Parallel Grid Side Rectifier and Series Grid Side Converte Fourth Power Conversion Conference (PCC), April 2-5, 2007 Doubly Fed Induction Generator, Dynamic Voltage Restorer, Voltage Sag Ride-Through, Wind Turbine. With steadily increasing wind turbine penetration, regulatory standards for grid interconnection have evolved to require that wind generation systems ridethrough disturbances such as faults and support the grid during such events. Conventional modifications to the doubly fed induction generation (DFIG) architecture for providing ride-through result in limited control of the turbine shaft and grid current during fault events. A DFIG architecture in which the grid side converter is connected in series as opposed to parallel with the grid connection has shown improved low voltage ride through but poor power processing capabilities. In this paper a unified DFIG wind turbine architecture which employs a parallel grid side rectifier and series grid side converter is presented. The combination of these two converters enables unencumbered power processing and robust voltage disturbance ride through. A dynamic model and control structure for this unified architecture is developed. The operation of the system is illustrated using computer simulations. P. FLannery, G. Venkataramanan
2007-003 003 CERTS Microgrid International Conference on System of Systems Engineering, April 16-18, 2007 San Antonio, TX. CHP, UPS, distributed generation, intentional islanding, inverters, microgrid, power vs. frequency droop, voltage droop. Application of individual distributed generators can cause as many problems as it may solve. A better way to realize the emerging potential of distributed generation is to take a system approach which views generation and associated loads as a subsystem or a “microgrid”. The sources can operate in parallel to the grid or can operate in island, providing UPS services. The system will disconnect from the utility during large events (i.e. faults, voltage collapses), but may also intentionally disconnect when the quality of power from the grid falls below certain standards. Utilization of waste heat from the sources will increase total efficiency, making the project more financially attractive. Field verification of the Consortium for Electric Reliability Technology Solutions (CERTS) microgrid control concepts are included. R.H. Lasseter
2007-004 004 A Magnetic Circuit Model for an IPM Synchronous Machine Incorporating Moving Airgap and Cross-Coupled Saturation Effects IEEE International Electric Machines and Drives Conference, May 3-5, 2007, Antalya, Turkey. component; Interior permanent magnet (IPM) synchronous machine; magnetic circuit model; cross-coupled magnetic saturation; moving airgap A new magnetic circuit model is presented for an interior permanent magnet (IPM) synchronous machine, using a machine with three-phase distributed stator windings and three layers of flux barriers in the rotor as an example topology. The model accounts for: i) the effects of cross-coupled magnetic saturation caused by the salient rotor; ii) variation of magnetic saturation levels in the iron rotor bridges that are key elements of the unitary rotor laminations; iii) the effects of stator lamination slots on the airgap mmf distribution; and iv) the local variation of airgap permeance due to the stator slotting and the relative position of the rotor with respect to the stator. As a result of these features, the new model is capable of significantly improving the accuracy of electromagnetic performance predictions for aggressively-designed IPM machines compared to previously-available magnetic circuit models. Comparisons with finite-element analysis and measurement results are provided showing that the new model is much faster while delivering appealing accuracy compared to the FE method. S.H. Han, T.M. Jahns, W.L. Soong
2007-005 005 Balanced Power Aggregation of Asymmetric Single-phase Systems IEEE Power Electronics Specialists Conference (PESC'07), June 2007, Orlando, FL, USA. Varying the relative voltage angle between phases can enable the power from three single-phase inverter systems to be aggregated to a constant value while maintaining themagnitudes of the voltages and serving asymmetrical loads. No additional passive elements are required. The concepts of instantaneous power spiral vectors and pulsating power spiral vectors are introduced to explain the theory, applicability, and limitations of this method. A closed loop voltage angle controller for the aggregation of three single-phase inverters to a common dc bus is presented. Computer simulations and laboratory experiments are performed to validate the theory. S. Bala, G. Venkataramanan
2007-006 006 Modeling and Control of the Static Synchronous Series Compensator under Different Operating Modes IEEE Power Electronics Specialists Conference (PESC'07), June 17-21, 2007, Orlando, FL, USA. This paper evaluates the dynamic performance of the Static Synchronous Series Compensator (SSSC) functioning under different operating modes. The SSSC uses a voltage source inverter to inject a series voltage in to the transmission line which is kept in quadrature with the line current. By adjusting the magnitude of this injected voltage, the active power flow through the line can be manipulated at will. The magnitude of the injected voltage can be set by commanding a value for the power through the line, a value of the injected voltage itself, or a value for the equivalent impedance seen by the line. This leads to three different operating modes, namely power mode, voltage mode and impedance mode. A dynamic model that allows controller design and performance evaluation under different modes is developed. Detailed computer simulations are used to contrast the performance of the SSSC under these three forms of operation. F. Mancilla-David, G. Venkataramanan
2007-007 007 Evaluation of Voltage Sag Ride-Through of a Doubly Fed Induction Generator Wind Turbine with Series Grid Side Converter IEEE Power Electronics Specialists Conference (PESC'07), June 17-21, 2007, Orlando, FL, USA. With steadily increasing wind turbine penetration, regulatory standards for grid interconnection have evolved to require that wind generation systems ridethrough disturbances such as faults and support the grid during such events. Conventional ride-through accommodations result in high currents and torque or are unable to ride-through down to zero volts. This paper explores two DFIG configurations in which a series grid side converter (SGSC) is employed exclusively for voltage sag ride-through. A control strategy applicable to both configurations is developed whereby the SGSC engages to stabilize the stator flux at the beginning and resolution of the sag event. Simulation results show excellent zero voltage ride-through response. P.S. Flannery, G. Venkataramanan
2007-008 008 Development of an Active dv/dt Control Algorithm for Reducing Inverter Conducted EMI with Minimal Impact on Switching Losses IEEE Power Electronics Specialists Conference (PESC'07), June 17-21, 2007, Orlando, FL, USA. This work investigates the use of an active gate control circuit to reduce the EMI produced by switching power converters. The active gate drive circuit makes it possible to adjust the voltage transition rate of a MOS-gated semiconductor switch on a pulse-by-pulse basis during PWM operation. This paper shows that tailored application of this circuit in a hardswitched inverter can be used to reduce theconducted commonmode EMI generated by the inverter while minimizing the incremental increase of the switching losses produced as a result of this control. An active dv/dt control algorithm that has been developed for a three-phase inverter to achieve this EMI reduction has been implemented for testing. Experimental results show that EMI can be reduced using this active dv/dtcontrol algorithm with lower total switching losses than a scheme that achieves a similar EMI reduction using adjustment of the gate drive resistors alone. J.D. Kagerbauer, T.M. Jahns
2007-009 009 Computer-Aided Controller Setting Procedure for Paper Machine Drive Systems IEEE IAS Pulp & Paper Industry Conference, June 24-28, 2007, Williamsburg, VA. Paper machine drive, speed and torque controllers, controller setting, torsional oscillations, disturbance rejection. This paper presents a comprehensive, three-stage computer-based methodology for the initial setting of the speed and torque controllers for the drives of a paper machine. First, the controller gains are selected based on the figures-of-merit for the frequency and time domain responses of each drive to commands and disturbances. After that, the effect of the elastic shafts is considered evaluating the resonant frequencies and 2M (two-mass) system responses. Finally, the responses of each group of drives to the process commands and/or disturbances of interest are evaluated. The use of the proposed methodology will assure fast and well-behaved responses of each group of drives of the different sections of a paper machine, with minimal field adjustments. M.A. Valenzuela, J.M. Bentley, R.D. Lorenz
2007-010 010 Power Converter Design for an Integrated Modular Motor Drive 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. integrated motor drive; PM motor drive; modular electronics; segmented stator; concentrated windings. The Integrated Modular Motor Drive (IMMD) concept provides a promising approach to integrating motor drive electronics into the machine housing by modularizing both the machine stator and the power converter. The basic module of the IMMD consists of a stator pole-piece wound with a concentrated coil and fitted with a dedicated power converter unit. This paper addresses several of the challenges associated with the design of an IMMD power converter module. In particular, the issues associated with configuring the dc bus capacitance to meet the demanding size requirements of the power converter are addressed, including the effect of dc bus connections. Experimental results for converter operation are presented, and opportunities to further reduce the capacitor size using active control strategies are discussed. N.R. Brown, T.M. Jahns, R.D. Lorenz
2007-011 011 An Analytical Design Approach for Reducing Stator Iron Losses in Interior PM Synchronous Machines during Flux-Weakening Operation 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. Interior permanent magnet synchronous machine; stator iron loss; flux weakening; multiple flux barriers Interior permanent magnet (IPM) synchronous machines are vulnerable to generating unacceptably large stator iron losses during flux-weakening operation at elevated speeds. The purpose of this paper is to present a new analytical design approach to reduce the stator iron losses in IPM machines with multiple flux barriers during flux-weakening operation. The proposed technique achieves this objective by: 1) designing the rotor to minimize the total harmonic distortion (THD) of the spatial distribution of the rotor scalar magnetic potential (mmf); and 2) coupling the rotor with an appropriate stator configuration to suppress undesirable higher-order harmonics in the stator as much as possible. An analytical design method is presented to synthesize the “minimum-THD” rotor with multiple flux barriers. Finite element analysis is used to demonstrate that the application of this design technique can lead to a substantial reduction of the stator iron losses during flux-weakening operation. S.H. Han, W.L. Soong, T.M. Jahns
2007-012 012 Torque Ripple Reduction in Interior Permanent Magnet Synchronous Machines Using the Principle of Mutual Harmonics Exclusion 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. interior permanent magnet machine; torque ripple; stator-rotor harmonic interactions; mutual harmonics exclusion The interior permanent magnet (IPM) synchronous machine is vulnerable to developing significant amounts of current-induced ripple torque depending on the details of the machine design. Building on the contributions of earlier researchers, this paper approaches the problem of torque ripple reduction in IPM machines by applying the principle of mutual harmonics exclusion. First, this paper develops a useful analytical expression for the torque ripple that highlights the stator-rotor harmonic interactions. Next, an analytical design procedure for IPM rotors with multiple flux barriers is proposed that applies the mutual harmonics exclusion principle in combination with stator windings that use odd numbers of slots per pole pair. Finally, the technique is applied to two example IPM machines to investigate the effectiveness of this approach using finite element analysis. Promising results predict that a low peak-to-peak torque ripple can be achieved using relatively small numbers of stator slots and rotor flux barriers for the full range of current control angles, including deep flux weakening. S.H. Han, T.M. Jahns, W.L. Soong
2007-013 013 Reducing Iron Loss in Interior PM Machines under Field-Weakening Conditions 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. iron loss, field-weakening, interior PM machines Field-weakening in interior PM machines is performed by using negative d-axis current to oppose the magnet flux and hence reduce the total fundamental d-axis flux at high speeds. Due to the rotor saliency, the d-axis current produces large amplitude harmonic airgap flux density components which can cause large harmonic stator iron losses. Reducing the magnet flux density reduces the required d-axis stator mmf to oppose it and hence reduces the field-weakening iron losses. However reducing the magnet flux density also reduces the magnet torque and hence increases the stator current requirement, particularly at lower speeds. This paper examines this trade-off for an automotive integrated starter/alternator using a graphical interior PM machine parameter plane approach. W.L. Soong, S.H. Han, T.M. Jahns, N. Ertugral
2007-014 014 Surface PM Machine Parameter Selection for Wide Field-Weakening Applications 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. surface PM machines, field-weakening, constant power speed range, characteristic current, parameter plane Recent work on fractional-slot pitch, concentrated winding (FSCW) surface PM machines has shown that these machines can achieve a wide constant-power speed range. This paper shows that defining the allowable machine design parameter plane using the characteristic current and the peak back-emf provides useful insights into how application requirements restrict the machine parameters. The parameter plane also shows the influence of changing the parameters on the machine’s current rating and magnet losses. As an example of a practical application, the parameter plane is used to study the FreedomCAR traction motor drive requirements and the characteristics of five FSCW surface PM machine designs. W.L. Soong, P.B. Reddy, A.M. El-Refaie, T.M. Jahns, N. Ertugral
2007-015 015 Dynamic Voltage Restorer Utilizing a Matrix Converter and Flywheel Energy Storage 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. dynamic voltage restorer, flywheel energy storage, indirect matrix converter, vector control, voltage sag A new series power conditioning system using a matrix converter with flywheel energy storage is proposed to cope with voltage sag problem. Previous studies have highlighted the importance of providing adequate energy storage in order to compensate for deep voltage sags of long durations in weak systems. With the choice of flywheel as a preferred energy storage device, the proposed solution utilizes a single ac/ac power converter for the grid interface as opposed to a more conventional ac/dc/ac converter, leading to higher power density and increased system reliability. The paper develops the dynamic model for the complete system including the matrix converter in dual synchronous reference frames coupled to the flywheelmachine and the grid, respectively. Thedynamic model is used to design a vector control system that seamless integrates functions of compensating load voltage and managing energy storage during voltage sag and idling modes. The numerical simulation results and experimental results from a laboratory-scale hardware prototype are presented to verify system performance. B. Wang, G. Venkataramanan
2007-016 016 Disturbance rejection limitations of back-emf based sensorless PM drives 2007 European Conference on Power Electronics and Applications (EPE), Sept. 2-5, 2007, Brussels, Belgium Sensorless Control, Permanent Magnet Motor, Modeling, Motion Control, Non-Linear Contro. The authors wish to acknowledge the financial support and motivation provided by Centro Federal de Educação Tecnológica do Maranhão (CEFET-MA), Brazil, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil, and the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC) of the University of Wisconsin – Madison. M.C. Harke, L.A. Ribeiro, R.D. Lorenz
2007-017 017 Implementation and Evaluation of a Stator and Rotor Flux Linkage Based Dead-beat Direct Torque Control of Induction Machines at the Operational Voltage Limits 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. induction machine, dead-beat control, direct torque control (DTC), voltage limits Dead-beat, direct torque (and flux) control of an induction machine is experimentally achieved at a 10 kHz sampling frequency. The inverse solution utilized lends itself to a very insightful graphical representation. This allows for an objective experimental evaluation of voltage vector choices in the operational voltage limits. The parameter sensitivity of the control algorithm is also investigated. N.T. West, R.D. Lorenz
2007-018 018 Digital Implementation of Both a Stator and Rotor Flux LinkageObserver and Stator Current Observer 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. induction machine, flux observer, current observer, dead-beat control, direct torque control (DTC), direct field orientation (DFO) Properly formed discrete time recursive models of a stator and rotor flux linkage observer are presented. A model delay in the flux linkage observer which hindered previous work is identified. To remove this delay, a new stationary frame current observer is developed and experimentally verified. With this new observer system, the flux linkages are properly estimated for the next sample instant, thus removing the computational delay. The improved and the delayed flux observer are evaluated in a dead-beat, direct torque control algorithm. N.T. West, R.D. Lorenz
2007-019 019 Effective Use of Miniature, Multi-point, Field-based Current Sensors Without Magnetic Cores 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. Field Detector; Giant Magnetoresistance; Integrated Current Sensor; Field Decoupling. A methodology for decoupling cross-coupled fields in compact, integrated current sensor arrays is presented. The compactness of the current sensor array elements is made possible by using highly sensitive field detectors based upon Giant Magnetoresistive (GMR) technology, which offers galvanic isolation, small size (~mm2) and high bandwidth (>1 MHz). By using known geometric relations between the conductor geometries and locations of the field detectors, cross-coupled magnetic field signals can be used to extract necessary current signals, as well as separate unknown disturbance fields. This methodology can also be used to simplify the magnetic biasing requirements of GMR field detectors, including decoupling of the temperature dependence of the biasing magnet. Moreover, the methodology also can be extended to estimate the temperature of the magnet to provide an extra temperature signal for thermal management algorithms. E.R. Olson, R.D. Lorenz
2007-020 020 Current Measurement Gain Tuning Using High Frequency Signal Injection 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. Accurate measurement of the phase currents in electric machines is a requirement for most high performance drives. Incorrect current measurement gain estimates, caused by device tolerances, temperature drifts, age and noise, reduce the accuracy of the current measurements and degrade the drive’s performance. This paper presents a method for compensating current measurement gain errors using a periodically injected, high frequency voltage. The positive and negative sequence components of the resulting high frequency current are measured and used for balancing and scaling the phase current measurement gains. The method can be used either as part of an initial commissioning, or start-up sequence, or periodically during the regular operation of the machine. M.C. Harke, J.M. Guerreo, M.W. Degner, F. Briz, R.D. Lorenz
2007-021 021 Discrete-Time Domain Modeling and Design for AC Machine Current Regulation 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. Current Regulator; Discrete-time domain AC machine modeling; Discrete-time domain complex vector current regulator Complex vector current regulators provide robust performance at high fundamental frequency operation, but there are difficulties in increasing the current regulation bandwidth and in operating at very high fundamental frequencies. In this paper, a discrete-time domain model of general AC machines is proposed. Based on this model, a discrete-time domain current regulator design methodology is proposed. This method is a generalization of the complex vector current regulator’s polezero cancellation approach and itfurthermore explicitly incorporates and compensates the control delay common in discrete-time implementations. K-K Huh, R.D. Lorenz
2007-022 022 SPMSM Design Considerations for Initial Position and Magnet Polarity Estimation using Carrier Signal Injection 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007. initial position estimation; machine design; polarity signals; sensorless; self-sensing; signal injection; SPMSM Initial position and magnet polarity estimation is required for smooth start-up of permanent magnet synchronous machines. The signal-to-noise ratio of the salient signals used for initial position and magnet polarity estimation depends on the machine design and affects the overall performance of the estimation technique. This paper investigates the design of a ring-magnet, surface permanent magnet synchronous machine to maximize the signal-to-noise ratio of the position and polarity signals without compromising the machine performance. Since the rotor geometry is fixed given the ring-magnet, the effect of the stator tooth tip geometry on the saliency signals is evaluated using finite element analysis. By adding a bridge between the stator teeth, the magnitude of the polarity-based signal can be increased significantly. A coupled simulation verifies the implementation of the improved initial position and magnet polarity estimation based on modified machine design. K. Akatsu, M.C. Harke, R.D. Lorenz
2007-023 023 Measurement and Adaptive Decoupling of Cross-Saturation Effects and Secondary Saliencies in Sensorless-Controlled IPM Synchronous Machines 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 23-27, 2007 This paper analyzes effects of magnetic saturation, including cross-saturation and secondary saliencies, on saliencybased sensorless control of interior PM synchronous machines. These effects are mitigated by adaptively decoupling saturation induced-saliencies via a structured neural network. The paper includes identification of the dominant, saturation-induced components of the carrier signal current interfering with the rotor position-dependent component being tracked, characterization of these components, and implementation of a non-linear, adaptive, saturation-induced components structured neural network model to perform their decoupling. D. Reigosa, P. Garcia, D. Raca, F. Briz, R.D. Lorenz
2007-024 024 Automatic Self-Commissioning for Secondary-Saliencies Decoupling in Sensorless-Controlled AC Machines Using Structured Neural Networks Proc. of IEEE International Symposium on Industrial Electronics (ISIE), June 4-7, 2007, Vigo, Spain. The focus of this paper is secondary-saliency decoupling in carrier signal injection-based sensorless control of AC machines using structured neural networks. Structured neural networks are utilized for automatic commissioning and decoupling of secondary saliencies including saturation-induced saliencies. Automatic commissioning process is necessary for easy implementation and for acceptance of the carrier signal injectionbased sensorless control by drivesindustry. In comparison with classical compensation methods, such as lookup tables, this technique has advantages of reducing commissioning time and automating the process. These advantages are result of a physicsbased design of structured neuralnetworks, which is responsible for their scalability, and moderate size and complexity. In comparison with traditional neural networks, structured neural networks are simpler, physically insightful, less computationally intensive and easier to train. P. Garcia, D. Reigosa, F. Briz, D. Raca, R.D. Lorenz
2007-025 025 Optimal Technology Selection and Operation of Microgrids in Commercial Buildings IEEE Power Engineering Society 2007 General Meeting (IEEE-PES 2007), 24-28 June, 2007 Tampa, FL, USA. buildings, building management systems, cogeneration, cooling, cost optimal control, dispersed storage and generation, distributed control, optimization methods, power system economics, power system planning The deployment of small (< 1-2 MW) clusters of generators, heat and electrical storage, efficiency investments, and combined heat and power (CHP) applications (particularly involving heat activated cooling) in commercial buildings promises significant benefits but poses many technical and financial challenges, both in system choice and its operation; if successful, such systems may be precursors to widespread microgrid deployment. The presented optimization approach to choosing such systems and their operating schedules uses Berkeley Lab’s Distributed Energy Resources Customer Adoption Model [DER-CAM], extended to incorporate electrical storage options. DER-CAM chooses annual energy bill minimizing systems in a fully technology-neutral manner. An illustrative example for a San Francisco hotel is reported. The chosen system includes two engines and an absorption chiller, providing an estimated 11% cost savings and 10% carbon emission reductions, under idealized circumstances. C. Marnay, G. Venkataramanan, M. Stadler, A. Siddiqui, R. Firestone, B. Chandran
2007-026 026 Small Signal Dynamics of Inverter Interfaced Distributed Generation in a Chain-Microgri IEEE Power Engineering Society 2007 General Meeting (IEEE-PES 2007), 24-28 June, 2007 Tampa, FL, USA. Distributed generation, Reactive power control, Frequency control Distributed Generation, or DG, involves utilization of small generators that are distributed in a power network, tosupply the electric power demands of utility customers. This paper presents the analysis of droop based generation control schemes for DG inverters comprising of active power-frequency and reactive power-voltage controllers. This enables decentralized operation with load sharing in a microgrid containing several interconnected DGs. Small-signal models are developed for microgrids consisting of several DGs connected in a chain topology. Mathematical propositions for stability are developed and guidelines are provided for design of controllers to meet the IEEE P1547 performance specifications. G. Venkataramanan, M. Illindala
2007-027 027 A General Modulation Strategy for a Five-level Three-Phase Current Source Inverter with Regulated Intermediate DC Link Currents. 2007 IEEE Industry Applications Society Annual Meeting, New Orleans, Sept. 20-24, 2007. Multilevel converters use series/parallelled semiconductor switching devices to synthesise switched waveforms at power levels that are well above individual device ratings. To date, most multilevel inverter research has focused on voltage source structures, primarily because these topologies address the more common high power converter limiting factor of device voltage ratings. However, multilevel current source converters can have advantages in lower voltage, very high current applications, or in situations where, despite their higher losses, DC inductors have reliability benefits compared to electrolytic capacitors. This paper presents an integrated three phase 5-level Current Source Inverter topology that requires only two intermediate link inductors, and shows how it can be controlled by mapping modulation control signals from a multilevel VSI controller. This allows the wealth of existing knowledge relating to modulation of multilevel VSI’s to be immediately applied to the multilevel CSI. The mapping process matches space vectors created by the VSI modulation process to equivalent CSI space vectors, and then selects between redundant space vector alternatives to maintain the current balance of the intermediate link inductors. The converter operation has been verified in a detailed circuit simulation taking account of all second order effects. Y.L. Familiant, D.G. Holmes, T.A. Lipo, B.P. McGrath
2007-028 028 Simulation of a Salient Pole Synchronous Machine with Both Field Pole and Stator Core Saturation Electromotion '07, Bordrum, Turkey, Sept. 10-12, 2007. Saturation effects in salient pole synchronous machines are generally modelled by assuming that the saturation effect is primarily limited to the field pole. However, saturation of the stator teeth and core can also become saturated such as when operating as a generator with a leading power factor load. This paper addresses the modeling and simulation of simultaneous saturation of both the stator and rotor taking into account the correct components of flux linkage which contribute to these effects. Suitable saturation curves are computed using finite element methods. Simulation results are shown using the new saturation model. T.A. Lipo, T. Komatsu, K. Shinohara
2007-029 029 Simulation of a High Temperature Superconducting Synchronous Machine with Stator Core Saturation AUPEC (Australasian Universities Power Engineering Conference) 2007. Perth, Australia. Dec . 10 - 12, 2007. Saturation effects in salient pole synchronous machines are generally modelled by assuming that the saturation effect is primarily limited to the field pole. However, a superconducting machine does not possess field pole saturation since it is free of iron. The stator, however, remains surrounded by an iron shell so that saturation of the stator core is possible. This paper addresses the modeling and simulation of the stator of a superconducting synchronous machine taking into account the correct components of flux linkage which contribute to this effect. Suitable saturation curves are computed using finite element methods. Simulation results are shown using the new saturation model. T.A. Lipo
2007-030 030 Modeling of Battery Charging Wind Turbines 7th International Conference on Power Electronics (ICPE). Daegu, Korea. Oct. 22-26, 2007. Small scale wind turbines are typically used in battery charging systems in off-grid and remote applications to provide electric power to small load locations such as homes, cabins and instrumentation stations. This paper is devoted to presenting the results from the modeling case-study of such a turbine. Analytical models, computer simulations and experimental results are presented. J. Reed, G. Venkataramanan, J. Rose
2007-031 031 Economic Factors and Incentives for Ocean Wave Energy Conversion IAS Annual Meeting '07. New Orleans, Lousiana. Sept. 23-27, 2007. ocean renewable energy, wave energy conversion Ocean energy conversion systems have recently seen renewed interest, stimulated mostly by today’s increasing energy discussions. In addition to ocean current energy converters, several commercial ocean wave energy projects have already been undertaken, but no clear economic model exists for developers to follow. Therefore, this paper focuses on U.S. economic factors that affect the use of wave power for generation of electric energy. These are addressed with regards to economic and business incentives for renewables and wave energy. The paper also investigates incentive programs needed to promote wave energy conversion technology. J.G. Vining, A. Muetze
2007-032 032 Governmental Regulation of Ocean Wave Energy Converter Installations IAS Annual Meeting '07. New Orleans, Louisiana. Sept. 23-27, 2007. ocean energy, renewable energy, wave energy conversion, legal jurisdiction and regulation Interest in ocean energy converter technology has increased with the revival of renewable energy awareness. To date, ocean current energy converters have been implemented with relatively mature technology when compared to wave energy converters. Despite the novelty of wave energy, several commercial wave energy projects have recently been undertaken. However, this process has not been accompanied by the development of a legal process for developers to follow. Therefore, this paper focuses on wave energy legal jurisdiction issues. These issues are addressed with regards to siting license dilemmas and which government agencies may assert jurisdiction. Regulatory actions needed to promote wave energy conversion technology are also investigated. J.G. Vining, A. Muetze
2007-033 033 Localized Aggregation of Diverse Energy Sources for Rural Electrification Using Microgrids Journal of Energy Engineering, Vol. 133, Num. 3, Sept. 2007, pp. 121-131. Energy; Dynamic stability; Developing countries; Electric power supply; Rural areas; Aggregates. Extension of electrical service to large rural populations in developing nations is a key requirement to realize human development goals set forth by international agencies. This paper presents the case for distributed generation in the form of microgrids, which should be the preferred path towards rural electrification in developing communities and a vital complement to expensive centralized grid expansion. The technical features of frequency and voltage control for distributed generation devices in a microgrid are discussed along with a presentation of their stability attributes. Computer simulation results and experimental results from a laboratory scale microgrid are also presented. M. Illindala, A. Siddiqui, G. Venkataramanan, C. Marnay
2007-034 034 Low Voltage Ride-Through Capability for Wind Turbines based on Current Source Inverter Topologies Seventh IEEE International Conference on Power Electronics and Drive Systems (IEEE PEDS 2007) November 27-30, 2007, Bangkok, Thailand. Current-Source Topology, Low Voltage Ride-Through, Open circuit fault, Wind Turbines. This paper proposes a circuital solution, aimed at a class of current-source inverter topologies, that provides the ability to ride-through temporary low voltage, as well as open circuit conditions at the mains without opening the mains circuit breakers. Although the proposed solution has broader applications, it is described in the framework of a previously published current-source inverter topology for modern wind turbines. For such systems, the low voltage ride-through capability is becoming a necessary feature. The current source topology considered exploits the cable length between the nacelle and the ground to provide a significant portion of the dc-link inductance. Prior work discussed the control strategy, flexibility, design rules, protection and experimental results of this topology and acknowledged the need for low-voltage ride through capability. One possible solution, derived from an already proposed protection scheme, is presented together with selected simulation and experimental results. P. Tenca, A.A. Rockhill, T.A. Lipo
2007-035 035 Analysis, Design and Evaluation of a Floating Capacitor Soft Switching High Power Single Phase Boost Rectifier ELECO 5th International Conference on Electrical and Electronics Engineering,December 2007, Bursa, Turkey, vol 2 (Electric Control), pp: 342-346,5-9. As the power levels of single phase boost converters used for unity power factor single phase ac rectification increases, there is need felt to employ soft switching to ameliorate the problems caused by the reverse recovery of the boost diode. This paper presents the analysis, computer simulation, and experimental evaluation of a soft switching approach for a boost power converter used for single phase power factor correction. Detailed modal analysis of the converter operation is presented in the paper followed by simulation and experimental results from a 10 kW experimental hardware prototype. A comparison of thermal performance of the approach with a hard-switched baseline using the exact same hardware platform is presented. Experimental results indicate a 30% reduction in heat sink temperature rise. N. Lebens, G. Venkataramanan, M.T. Aydemir
2007-036 036 Modeling of Saturated Induction Machines With Injected High-Frequency Signals IEEE Transaction on Energy Conversion, Vol. 22, Issue 4, Dec. 2007 pp. 819 - 828. Air-gap flux harmonics, flux position estimation, q-d model, saturation modulation, sensorless control. This paper analyzes the effects of injecting additional signals in induction machines for the purpose of speed control. A new saturation model able to correctly model the interaction between the added signal and saturation of the motor core due to the main torque-producing flux is presented. The introduction of a variable saturation factor is used to model the variation of the saturation level due to the additional signal. A third harmonic rotor circuit is also introduced to take account of the third harmonic component of the air-gap flux, due to saturation. An additional balanced voltage set is added to the normal supply to analyze the effects of such signals on a saturated induction motor. Simulation results of such a model both at no load and full load are presented together with experimental measurements. G. Bottiglieri, A. Consoli, T.A. Lipo
2007-037 037 Digital Implementation of Both a Stator and Rotor Flux Linkage Observer and Stator Current Observe Proc. of IEEE IAS Conf., Sep. 23-27, 2007. induction machine, flux observer, current observer, dead-beat control, direct torque control (DTC), direct field orientation (DFO) Properly formed discrete time recursive models of a stator and rotor flux linkage observer are presented. A model delay in the flux linkage observer which hindered previous work is identified. To remove this delay, a new stationary frame current observer is developed and experimentally verified. With this new observer system, the flux linkages are properly estimated for the next sample instant, thus removing the computational delay. The improved and the delayed flux observer are evaluated in a dead-beat, direct torque control algorithm. N.T. West, R.D. Lorenz
2007-038 038 Self-Sensing as an Integration Focus for Motor Drives and Power Devices Proc. of the International Conference on Electrical Machines and Systems (ICEMS), Oct. 8-11, 2007. Self-Sensing; Sensor Integration; MultiFunctional Design; Spatial Design Self-sensing (sensorless or fully integrated sensing) methods in motor drives and power devices is a major opportunity to extend the early generations of fully integrated sensing to become central to the next generation of motor drive and power device design. To achieve the next level of integration, solutions that cross technology boundaries and are intrinsically multi-functional will be required, whereby the design-for-selfsensing in all actively controlled devices will be the norm. This paper and presentation will focus on the critical elements of the new multi-disciplinary self-sensing paradigm as it applies to both machine and power devices used in motor drives and all forms of power conversion equipment. R.D. Lorenz
2008-001 001 A Comparative Evaluation of Series Power Flow Controllers Using DC and AC Link Converters IEEE Transactions on Power Delivery. F. Mancilla-David, S. Bhattacharya, G. Venkataramanan
2008-002 002 A 3-D Magnetic Charge Finite-Element Model of an Electrodynamic Wheel IEEE Transactions on Magnetics, Vol. 44, No. 2, February 2008. J. Bird, T.A. Lipo
2008-003 003 A Comparative Analysis of Pulsating vs. Rotating Vector Carrier Signal Injection-Based Sensorless Control Proc. of IEEE APEC Conf., February 24-28, 2008. This paper analyzes the sensitivity to non-ideal physical attributes of pulsating and rotating vector carrierinjection based sensorless techniques, as well as of the impact on the accuracy and robustness of the sensorless control. The analysis is mainly done on the basis of terminal attributes of machines. Initial observations on the subsequent finite element study are also given. Commonly used filtering and position estimation techniques associated with each carrier signal are considered. The analysis is supported by experimental evidence obtained using interior PM synchronous machines, but the findings are applicable to other AC machines as well. D. Raca, P. Garcia, D. Reigosa, F. Briz, R.D. Lorenz
2008-004 004 Sinusoidal Surface-Mounted PM Machine Drive Using A Minimal Resolution Position Encoder Proc. of IEEE APEC Conf., February 24-28, 2008. This paper presents a high resolution position estimation system for sinusoidal surface PM machines based on a vector-tracking observer and a 90° resolution encoder. It is shown here that this is the minimum amount of resolution needed for sinusoidal PM drives. The key implementation issues of this system are presented, and stability analysis is performed, leading to the definition of local stability limits, within which the actual position is tracked with bounded estimation error. The effect that non-uniform sector widths have on position estimation is also explored and a straightforward compensation method is proposed. Both simulation and experimental testing illustrate the performance and limitations of the proposed observer topology and of the drive when this observer is used for state feedback. G. De Donato, Mc.C. Harke, F. Guilii Capponi, R.D. Lorenz
2008-005 005 Modeling of Battery-Charging Wind Turbines With Yaw Axis Furling 1st EPE Wind Energy Chapter Seminar, March 27-28, 2008. Battery charger, Electrical machine, Energy storage, Renewable energy systems, Wind generator systems. This work was supported in part through a sabbatical grant from the University of Wisconsin-Madison, and research and education grants from the Brazilian National Council for Scientific and Technological Development (CNPq), and The Scientific and Technical Research Council of Turkey, (TÜB?TAK). The authors would like to acknowledge the support from the sponsors of the Wisconsin Electric Machines andPower Electronics Consortium for the laboratory investigations. The prototype design assistance from Hugh Piggot, at Scoraig Wind Electric, Scotland, is gratefully acknowledged. J. Reed, G. Venkataramanan
2008-006 006 Comparison of Zero Current and Zero Voltage Switching PWM method of the Dual Bridge Matrix Converter. IEEE Energy Conversion Congress and Exposition, 2009. ECCE 2009. power cycle, dual bridge matrix converter, Mean Time to Failure (MTTF), zero voltage switching, zero current switching The paper investigates the difference of two PWM control methods for dual bridge matrix converters (DBMC). The first method is well known and allows zero current switching of the rectifier side switching. The second method is proposed by this paper which allows zero voltage switching in the inverter IGBTs. This paper analyses the power losses and lone term reliability of IGBT modules in the DBMC used as a motor drive for both methods. It was shown that the switching losses of the IGBT for DBMC can be shifted between the rectifier and inverter by switching the two PWM control method. As a result, the DBMC shows some advantages over other topologies in terms of the sizing of the IGBT, balancing of the thermal system and easier to operate under higher switching frequency conditions. L. Wei, T. Lipo, R. Lukaszewski
2008-007 007 Control of Bi-Directional Z-Source Inverter The 34th Annual Conference of the IEEE Industrial Electronics Society (IECON 2008), Orlando, Florida, USA, 10-13 Nov, 2008. Z-source inverter, DCM mode A new topology bi-directional Z-source inverter is proposed in this paper. It can overcome the uncontrollable and unstable limitations of the Z-source inverter in the discontinuous conduction mode (DCM). The operating principle, switching signal flow graph model and transfer function for the circuit are developed. In addition, the system stability and dynamic performance are analyzed thoroughly. Due to the presence of two control variables D and M, the control of the system is very nonlinear. A dual closed loop controller is proposed to improve the stability and dynamic performance. A prototype of a 55kVA bidirectional Z-source inverter is designed to verify the principle and demonstrate the performance of the proposed topology. H. Xu, T. Lipo, L. Kong
2008-008 008 Test And Evaluation Of DC Power Supplies In High-Frequency AC Microgrids The 34th Annual Conference of the IEEE Industrial Electronics Society (IECON 2008), Orlando, Florida, USA, 10-13 Nov, 2008. Distributed generation, Microgrids, DC power supply A 600Hz single phase High Frequency AC microgrid has been proposed to integrate the renewable source and load. In order to test the functions and evaluation the performance of DC power supply in this new 600Hz system, two types of DC power supply, the linear rectifier power supply and switch mode DC power supply, were tested and evaluated in this paper. The test method and experiment results of line regulation and/or load regulation, dynamic characteristics, heat, noise, inputs power factor, efficiency, input harmonics of DC power supply are provided. The analysis and explanation are given. Both types of DC power supply can not only function successfully when directly connected to a 600 Hz AC source, but can have superior performance and higher efficiency operating in a 600Hz than 60Hz system. H. Xu, D. Pan, Y. Wang, T. Lipo
2008-010 010 The Emerging Role Of Dead-Beat, Direct Torque And Flux Control In The Future Of Induction Machine Drives IEEE OPTIM Conf., May 22-24, 2008, Brasov, Romania. induction machines, dead-beat (DB) control, direct torque control (DTC), direct torque and flux control (DTFC), voltage limits Induction machine drives have the potential to be a highly efficient candidate for variable load power conversion applications dominated by low per unit torque, medium speed duty cycles. To achieve efficiency, the key control variable is flux linkage, which is central to direct torque and flux controlled (DTFC) drives. Deadbeat DTFC drives, by switching at fixed rates, can seamlessly handle voltage/current limits, as well as with zero speed self-sensing methods. This paper explores the methods to achieve true deadbeat, DTFC control, deal with voltage and current limits, and be suitable for loss minimizing control and zero speed self-sensing control. R.D. Lorenz
2008-011 011 Dynamic On-line Sensing of Sheet Modulus of Elasticity Proc. of IEEE IAS Pulp & Paper Industry Conf., June 22-27, 2008, Seattle, WA, pp. 35-45.IEEE Trans. on Ind. Appl., Vol 46, No. 1, Jan/Feb 2010, pp. 108-120. M.A. Valenzuela, J.M. Bentley, R.D. Lorenz
2008-012 012 Input Harmonic Estimation and Control Methods in Active Rectifiers IEEE Power Electronics Specialists Conference (PESC'08), June 15-19, 2008, Rhodes, Greece. Active rectifiers using PWM voltage-source converters (VSCs) are popular choices for adjustable-speed drives to provide high input power quality. However, input current harmonics are often generated as a result of input voltage source disturbances. Since the frequencies of the 5th-, 7th-, and higher-order harmonics can easily exceed the current controller bandwidth in high-power applications, the elimination of these harmonic disturbances imposes difficult control challenges. Cost-effective observer-based harmonic estimation and mitigation methods are introduced in this paper that compensate delay effects caused by the digital signal processing. Such delays can significantly limit the current controller bandwidth if not compensated. Analytical, simulation, and experimental results are developed to illustrate the effectiveness of the new harmonic estimation and control techniques. K. Lee, V. Blasko, T.M. Jahns, T.A. Lipo
2008-013 013 New Observer-based Source Voltage Unbalance Control Methods in PWM Voltage-Source Converters IEEE Power Electronics Specialists Conference (PESC'08), June 15-19, 2008, Rhodes, Greece. Unbalanced input voltages can degrade the performance of voltage-source converters (VSC) by injecting a second harmonic voltage component onto the dc link voltage (120 Hz for 60 Hz system) that reduces the dc link capacitor lifetime and disturbs the performance of the attached inverter load. These negative effects can be eliminated if the voltage-source converter includes an active front-end (AFE) converter stage with appropriate control. New observer-based disturbance estimation and control algorithms are introduced in this paper that compensate source voltage unbalances. The algorithms are also designed to compensate the detrimental impact of delay effects caused by the digital signal processing. Consequently, these techniques are appropriate for higher-power systems with reduced PWM switching frequency and limited current controller bandwidth. Analytical, simulation, and experimental results are presented to illustrate the effectiveness of the new observer-based control techniques. K. Lee, T.M. Jahns, T.A. Lipo, V. Blasko
2008-014 014 Inverter Gate Drive and Phase Leg Development for 175°C Operation Proc. of IEEE PELS PESC Conf., June 15-19, 2008, Rhodes, Greece, pp. 2152-2158. An inverter phase leg has been developed that can operate in an ambient temperature up to 175 degrees Celsius using commercially-available components to the greatest possible extent. This phase leg includes a discrete gate drive circuit that incorporates both level-shifting and isolated power supply functions. A high-temperature prototype gate drive has been built and tested using smallsignal bipolar transistors and diodes combined with suitable high-temperature passive components rated for operation at temperatures up to 200°C. A SPICE model was developed to study the gate drive operating characteristics over a wide temperature range from 25 to 175°C. Measured results closely match the simulation results. In addition, the gate drive circuit has been tested as part of a complete half-bridge inverter utilizing a pair of silicon carbide DMOSFETs and Schottky diodes together with stacked ceramic capacitors. Experimental results show that the gate drive and phase leg performance characteristics are well behaved at all temperatures up to 175°C. D.M. Springmann, T.M. Jahns, R.D. Lorenz
2008-015 015 A Larger Role for Microgrids IEEE Power & Energy Magazine, Vol. 6, Num. 3, May/June 2008, pp.78-82. G. Venkataramanan, C. Marnay
2008-016 016 Analytical Solution for Cogging Torque in Surface Permanent-Maget Motors Using Conformal Mapping IEEE Transactions on Magnetics, Vol. 44, No. 1, January 2008, pp. 52-65. D. Zarko, D. Ban, T.A. Lipo
2008-017 017 The Operation of Diesel Gensets in a CERTS Microgrid 2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century. Power generation control, AC generator excitation, microgrid, diesel genset, DER. In this paper the operation of diesel engine-driven wound-field synchronous generator sets as Distributed Generators (DG’s) is studied. The objective of this work is to develop the modeling and control framework for such gensets to enable their operation in a distribution system that contains multiple DG’s including inverter-based sources. The paper presents experimental results for the interaction of conventional gensets with inverter-based sources in a microgrid test system. From the test results it is observed that there is significant circulating reactive power between the sources as well as frequency oscillations caused by the response of the conventional genset controller. A new controller for the genset is proposed that alleviates these issues and enables the various sources to share power and maintain power quality within the system. The operation of the new controller is demonstrated using simulation results. S. Krishnamurth, T.M. Jahns, R.H. Lasseter
2008-018 018 An Active Common Mode EMI Filter For Switching Converters IEEE IAS Annual Meeting, Oct. 08. Actve filtering, Conducted EMI, Common-mode noise, EMI mitigation Conducted electromagnetic interference resulting from common mode noise currents are a significant problem with switching power converters. Such noise current arises as result of the broadband nature of the switching waveforms that are coupled into the ground through parasitic capacitive paths. It is common to employ passive LC-filters to mitigate common mode noise keeping the noise levels below applicable regulatory limits on emissions. The work presented herein focuses on a circuit configuration including active components that aids the LC filter to suppress external common mode emissions. The paper presents a qualitative development, design oriented analysis of the proposed approach and experimental evaluation verifying its performance. N. Mortenson, G. Venkataramanan
2008-019 019 Power Quality Conditioning Using Bridged T-Filters For Passive Rectifiers IEEE IAS Annual Meeting, Oct. 08. Three phase rectifier harmonics, harmonic filtering, bridged-T filters, voltage imbalance mitigation Harmonic standards such as IEEE 519 have prompted the adoption of active rectifiers or the use of multiple pulse rectifiers for three phase ac-dc conversion system in variable speed drives and other applications. Although active rectifiers are capable of excellent line current waveforms and dc bus regulation, they do result in increased EMI at the input terminals. On the other hand, passive filters typically require a modest amount of reactive elements if configured appropriately. This paper presents the application of a passive filter for input current filtering for passive rectifiers. Filter design equations and operation during voltage imbalances are discussed. Computer simulation and experimental results are presented that verify the operation of the filter. S. Fredette, G. Venkataramanan
2008-020 020 Unbalanced Voltage Sage Ride-Through Of A Doubly Fed Induction Generator Wind Turbine With Series Grid Side Converter IEEE IAS Annual Meeting, Oct. 08. doubly fed induction generator; voltage sag; voltage dip; unbalance; low voltage ride-through; wind turbine Regulatory standards for grid interconnection require wind generators ride-through disturbances such as faults and support the grid during such events. Conventional accommodations for providing voltage sag ride-through for doubly fed induction generator (DFIG) wind turbines result in compromised control of the turbine shaft and grid current during unbalanced faults. This paper presents analysis and control design of a DFIG wind turbine with series grid side converter for ride through during unbalanced voltage sag events. A dynamic model and control structure is developed for unbalanced operating conditions. Experimental results from 2kW laboratory hardware are used to verify the proposed concepts. Hardware results illustrate excellent ride throug P. Flannery, G. Venkataramanan
2008-021 021 Current Source Topology for Wind Turbines With Decreased Mains Current Harmonics, Further Reducible via Functional Minimization IEEE Transactions on Power Electronics, Vol. 23, No. 3, May 2008, pp. 1143-1155. P. TEnca, A. Rockhill, T.A. Lipo, P. Tricoli
2008-022 022 Strand-Level Proximity Losses in PM Machines Designed for High-Speed Operation 2008 Intl Conf. on Electrical Machines (ICEM'08), Vilamoura, Portugal, Sept. 6-9, 2008. AC losses, brushless machines, high speed, permanent magnet, proximity loss. The stator windings of surface PM synchronous machines with fractional-slot concentrated windings are vulnerable to high proximity losses when operated at high speeds due to their typically high pole numbers and resulting high electrical frequencies. The limitations of an existing 1-D flux density model are demonstrated and an improved 2-D analytical model is introduced for estimating flux densities and stand-level proximity losses inside the slots. The 2-D analytical model is shown to provide good matches with finite element analysisfor the predicted flux densities and proximity losses inside a rectangular slot with a variable slot opening and electricalfrequency. P.B. Reddy, Z.Q. Zhu, S. Han, T.M. Jahns
2008-023 023 Carrier Signal Selection for Sensorless Control of PM Synchronous Machines at Zero and Very Low Speeds Proc. of IEEE IAS Conf. Oct. 5-9, 2008, Edmonton, Canada, IEEE Trans. on Ind. Appl., Vol 46, No. 1, Jan/Feb 2010, pp. 167-178. This paper compares pulsating- and rotating-vector carrier-signal injection for self-sensing (or sensorless) control of permanent-magnet synchronous machines (PMSMs). The main focus of this paper is the evaluation of estimation errors due to the physical nonideal attributes of both the machine and the inverter. Initial-position and magnet-polarity estimations are analyzed as well. Transient response and signal processing for both techniques are discussed for completeness. The theoretical analysis is supported by experimental and simulation evidence obtained using interior PMSMs. D. Raca, P. Garcia, D. Reigosa, F. Briz, R.D. Lorenz
2008-024 024 Analysis and In-Situ Measurement of Thermal-Mechanical Strain in Active Silicon Power Semiconductors Proc. of IEEE IAS Conf. Oct. 5-9, 2008, Edmonton, Canada. Thermal-mechanical strain in silicon power devices is investigated using both finite element models and experimental techniques so that the reliability of power electronics modules can be improved by actively regulating strain to help guarantee predictable life while fully utilizing the capability of the device. Near-infrared photoelastic strain measurement and threedimensional finite element modeling are applied to quantifying the critical strain magnitudes and locations during operation. Three-dimensional, transient, thermal-mechanical finite element models of IGBT devices are presented. Experimental results verifying the electrical-loss-driven thermal-mechanical strain in an electrically active discrete IGBT device are provided. M.L. Spencer, R.D. Lorenz
2008-025 025 Modeling and Adaptive Decoupling of Transient Resistance and Temperature Effects in Carrier-based Sensorless Control of PM Synchronous Machines Proc. of IEEE IAS Conf. Oct. 5-9, 2008, Edmonton, Canada, IEEE Trans. on Ind. Appl., Vol 46, No. 1, Jan/Feb 2010, pp. 139-149. This paper analyzes the effects of the transient resistances in saliency tracking-based sensorless control methods of PM synchronous machines. A high frequency model of the PM synchronous machine including both stator and rotor transient resistance is presented. From this model, potential sources of error in the estimated position due to the transient resistances are analyzed, and their compensation by means of an adaptive decoupling mechanism is proposed. The paper also addresses the influence and compensation of temperature effects in carrier signal injection-based sensorless techniques.a D. Reigosa, P. Garcia, F. Briz, D. Raca, R.D. Lorenz
2008-026 026 Digital Charge Control of Boost Converter with Constant Power Machine Load ICEMS 2008, The 11th International Conference on Electrical Machines and Systems, Wuhan, China, Oct.17-20, 2008. charge control; DC-DC converter This paper proposes the digital charge control method to boost converter operating with a type of nonlinear load, the constant power load. The constant power load is modeled theoretically, and model parameters are given in detail. Transfer functions of the boost converter with constant power load are deduced, and a small-signal model of the charge controlled current inner loop is presented. The Digital Charge Control method (DCC) is implemented with TMS320LF2407. A novel Digital Forecasting Charge Control method (DFCC) is proposed to eliminate the defect of dutycycle jumping. The system stability anddynamic performance are analyzed thoroughly. Experimental results confirm that DFCC boost converter operating with the constant power machine load can follow the reference stably and rapidly. H. Xu, X. Wen, T.A. Lipo
2008-027 027 Test and Evaluation of Lighting System in High-Frequency AC Microgrids ICEMS 2008, The 11th International Conference on Electrical Machines and Systems, Wuhan, China, Oct.17-20, 2008. Distributed generation, Microgrid, Lighting systems A 600Hz single phase high frequency AC microgrid is proposed to integrate the renewable source and load. In order to provide insights of how lighting systems can be adjusted to work more efficiently with high frequency power source. This paper is devoted to a study of the illumination intensity and efficiency changes of current household lighting systems under high frequency operating conditions. Comparisons of performance under different working frequencies are explained. Two types of lighting system, incandescent lamps and fluorescent lamps with magnetic ballast, were tested and evaluated. The experiments results of current & input power, illumination intensity and illumination efficiency, heat, power factor and starting voltage of lighting system have been obtained. It was determined that both types of lighting systems can function when directly plugged into 600 Hz AC source, and that they have superior performance and higher efficiency using a 600Hz than a 60Hz system. H. Xu, Y. Wang, D. Pan, T.A. Lipo, L. Kong
2008-028 028 Interior Permanent Magnet Synchronous Motor Design for Improving Self-sensing Performance at Very Low Speed Proc. of 13th Int'l Conf. on Electrical Machines and Systems, ICEMS, Oct. 17-20, 2008, Wuhan, China, ppr. SMP-59, IEEE Trans. on Ind. Appl., Vol 45, No. 6, Nov/Dec 2009, pp. 1939-1946. Carrier signal injection, field-intensified permanent-magnet synchronous machines, saturation effects,self-sensing. The focus of this paper is to improve the selfsensing performance of an interior permanent-magnet synchronous machine (IPMSM) by modifying the rotor configurations. A field-intensified IPMSM (FIIPMSM) is designed by adding flux barriers in the rotor of an IPMSM. In comparison with IPMSMs, FIIPMSMs have the advantage of decoupling saturation-induced saliency, cross-coupling effects, and also secondary saliencies, which reduce the estimation accuracy of self-sensing control for IPMSMs. A finite element analysis is used to design the FIIPMSM and assess the performance of the machine for self-sensing. The self-sensing capabilities of IPMSMs and FIIPMSMs are presented and compared. The results demonstrate the improved self-sensing performance of the new field-intensified machine. S. Wu, D.D. Reigosa, Y. Shibukawa, M.A. Leetmaa, R.D. Lorenz, Y. Li
2008-029 029 Study of a Novel Double Two-Phase Machine Drive System International Conference on Electric Machines, Wuhan, China. Sept. 2008. Topology, a two-phase machine, simulation. A novel topology of a double two-phase machine drive system is proposed. It is shown that by connecting the neutral lines of a two-phase permanent magnet machine(TPPM) and a two-phase induction machine(TPIM), only four switches need to be used for each machine and the two machines share one set capacitors. This paper develops the mathematical model of this system and establishes the simulation model accordingly. Simulation results are given to demonstrate the feasibility of the concept. The results obtained in this paper shows that the novel double two-phase machine system has promising potential. B. Wang, T.A. Lipo, G. Wei, J. Chu
2008-030 030 Analysis of Power Cycling Capability of IGBT Modules in a Conventional Matrix Converter IEEE Industry Applications Society Annual Meeting, 5-9 Oct. 2008. power cycle, thermal cycle, conventional matrix converter, Mean Time to Failure (MTTF) this paper analyzes the power cycling capability of IGBT modules in a conventional matrix converter used as a motor drive. The analysis is made under various condition for this topology, including low speed operation capability, high speed thermal and power cycle capability and etc. It was found that the power cycling Mean Time to Failure (MTTF) of IGBT in a matrix converter is low when the input and output frequency is close to each other or when the output frequency of the converter is low. As a result, the chip size of the conventional matrix converter may be larger than the other candidates. In the end of the paper, some guidance of designing a matrix converter for long term reliabilities is also discussed. L. Wei, T.A. Lipo, A. Lukaszewski
2008-031 031 Bearing Damage Analysis by Calculation of Capacitive Coupling Between Inner and Outer Races of a Ball Bearing Proc. of EPE-PEMC Conf., Poznan, Poland, Sept. 1-3, 2008, pp. 903-907. bearing failure, capacitive coupling, discharge current, shaft voltage, symmetrical and asymmetrical shaft position bearing damage in modern inverter-fed AC drive systems is more common than in motors working with 50 or 60 Hz power supply. Fast switching transients and common mode voltage generated by a PWM inverter cause unwanted shaft voltage and resultant bearing currents. Parasitic capacitive coupling creates a path to discharge current in rotors and bearings. In order to analyze bearing current discharges and their effect on bearing damage under different conditions, calculation of the capacitive coupling between the outer and inner races is needed. During motor operation, the distances between the balls and races may change the capacitance values. Due to changing of the thickness and spatial distribution of the lubricating grease, this capacitance does not have a constant value and is known to change with speed and load. Thus, the resultant electric field between the races and balls varies with motor speed. The lubricating grease in the ball bearing cannot withstand high voltages and a short circuit through the lubricated grease can occur. At low speeds, because of gravity, balls and shaft voltage may shift down and the system (ball positions and shaft) will be asymmetric. In this study, two different asymmetric cases (asymmetric ball position, asymmetric shaft position) are analyzed and the results are compared with the symmetric case. The objective of this paper is to calculate the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races. J. Adabi, F. Zare, G. Ledwich, A. Ghosh, R.D. Lorenz
2008-032 032 Optimal Skew Angle for Improving of Start-Up Performance of a Single-Phase Line-Start Permanent Magnet Motor Proc. of IEEE IAS Conf. Oct. 5-9, 2008, Edmonton, Canada. back EMF, FEM, Line start permanent magnet motor, Multi-slice, Skew This paper deals with the skew effects on starting characteristics of a line-start permanent-magnet motor (LSPM). Considering structural constraints of a rotor of an LSPM, we propose a stator-skewed core. With variation of the skew angle of stator core, the back EMF and the start-up characteristics are analyzed, and the optimal angle to maximize the start-up performance is searched. For analysis considering the 3D-effects of skewed structure, we apply the 2D FEM with multi-slice combination technique. The optimal skewed model and a non-skewed model are fabricated, tested and validated experimentally. B. Kim, D. Kim, B. Kwon, T.A. Lipo
2008-033 033 Winding Inductances of Fractional Slot Surface-Mounted Permanent Magnet Brushless Machines Proc. of IEEE IAS Conf. Oct. 5-9, 2008, Edmonton, Canada. concentrated windings; fractional-slot windings; flux-weakening; permanent magnet synchronous machine; surface PM machine; inductance. Permanent Magnet (PM) brushless machines equipped with Fractional-Slot Concentrated-Windings (FSCW) have been receiving considerable attention over the past few years, due to the fact that they have short end-windings, a high slot fill factor, a high efficiency and power density, and good fluxweakening and fault-tolerancecapabilities. A key design parameter for such machines is the phase winding inductance since this has a significant impact on the performance, as well as on the magnitude of any reluctance torque. The paper describes a detailed investigation of the various components of the winding inductance in machines equipped with both overlapping and nonoverlapping windings and different slot/pole number combinations. It also examines the influence of key design parameters, which affect the inductance components, with particular reference to the inductances of machines in which all the teeth are wound and those in which only alternate teeth are wound. It is shown that the main component of the winding inductance is the relatively large slot leakage component. Both analytical and finite element models are employed and predicted results are validated on several prototype machines. A.M. El-Refaie, Z.Q. Zhu, T.M. Jahns, D. Howe
2008-034 034 Analysis of Rotor Core Eddy-Current Losses in Interior Permanent Magnet Synchronous Machines Proc. of IEEE IAS Conf. Oct. 5-9, 2008, Edmonton, Canada. IPM machines; rotor core eddy-current losses; one- and two-layer rotors; concentrated- and distributed- winding stators This paper presents the results of an investigation focused on the rotor core eddy-current losses of interior permanent magnet (IPM) synchronous machines. First, analytical insight into the rotor core eddy-current losses of IPM machines is developed. Next, major design parameters that have the most significant impact on the rotor core eddy-current losses of IPM machines are identified. Finite element analysis results are then presented to compare the predicted eddy-current losses in the machine core of IPM machines with one- and two-layer rotors coupled with concentrated- and distributed-winding stators. It is shown that the lowest total eddy-current losses in the machine core are achieved using a combination of distributed stator windings and two magnet layers per rotor pole, while minimizing only the rotor core eddy-current losses favors replacement of the rotor with a single-layer configuration. S.-H. Han, Z.Q. Zhu, T.M. Jahns
2008-035 035 Design Tradeoffs between Stator Core Loss and Torque Ripple in IPM Machines Proc. of IEEE IAS Conf. Oct. 5-9, 2008, Edmonton, Canada. IPM machines; stator core losses; flux-weakening; torque ripple; magnet layers; stator slots-per-pole-pair High stator core losses can pose a significant problem in IPM machines operating over wide constant-power speed ranges. At lower speeds, the torque ripple can be undesirably large in some IPM machine designs, contributing to acoustic noise and vibration. While previous work has addressed these two problems independently, this paper shows that the conditions for reducing stator core losses during flux-weakening operation, dominated by harmonic eddy-current losses in the stator teeth, can conflict with the conditions for reducing the torque ripple of IPM machines. It is also shown that the resulting design tradeoffs depend on the details of the IPM machine topologies that are under consideration. The appropriate IPM machine topologies that offer more favorable tradeoffs are identified in order to achieve the best possible compromise of high-speed stator core losses and torque ripple characteristics. S.-H. Han, Z.Q. Zhu, T.M. Jahns
2008-036 036 Impact of Winding Layer Number and Slot/Pole Combination on AC Armature Losses of Synchronous Surface PM Machines Designed for Wide Constant-Power Speed Range Operation Proc. of IEEE IAS Conf. Oct. 5-9, 2008, Edmonton, Canada. Strand AC losses; fractional-slot; concentrated winding; surface permanent magnet machine; armature loss; high frequency; flux weakening; This paper examines the impact of the winding layer number (single- and double-layer), and magnet type (sintered and bonded), as well as slot/pole combinations on AC stator losses in surface permanent magnet (SPM) synchronous machines equipped with fractional-slot concentrated windings that are designed for wide speed ranges of constant-power operation. It is shown that the use of bonded magnets instead of sintered magnets tends to increase the AC losses, while magnetic saturation of the tooth-tips tends to reduce these losses. The effect of terminal conditions, i.e. series and parallel connections, on AC losses is also investigated. The effect of leakage flux on AC losses is studied for the various slot/pole combinations within the same slot/pole/phase (spp) family as well as for different sppvalues, indicating that high numbers of stator poles tend to increase the AC losses. An AC loss index has been defined incorporating these effects to serve as a quick screening tool for the various slot/pole combinations under consideration. P.B. Reddy, T.M. Jahns, A.M. El-Refaie
2008-037 037 Reactive Compensation Needs for Superconducting Transmission Systems Proc. of IEEE Conference on Applied Superconductivity, Chicago, Aug. 2008. Superconducting cables, Power system dynamic stability, Reactive power control, Voltage control Replacing conventional ac transmission lines with superconducting cables provides many potential advantages, including strengthening the dynamic coupling of the power system since superconducting cables have much lower series inductance than overhead lines in addition to the greatly reduced resistance. This will make the transmission lines appear electrically shorter and can eliminate the need to install shunt capacitors for transmission voltage support or the need to install series capacitors to make lines appear electrically shorter to improve system performance. The superconducting cable performance characteristics will be dominated by shunt parasitic capacitance charging affects, much as is the case with conventional underground cables. However, the low series impedance of the cable improves the voltage regulation across the cable. As a result, ac superconducting cables could face less severe distance limits than conventional cables before reactive compensation is required in the middle of the cable to correct for the effects of this capacitance. However, the capacitive current will still need to be compensated at the end point terminations. In addition, superconducting systems have less inherent damping for electromechanical disturbances. The compensation scheme will need to address these needs as well. B.K. Johnson, J.M. Appikonda, G. Venkataramanan
2008-038 038 The Operation of Diesel Gensets in a CERTS Microgrid Proc. of IEEE Power & Energy Society Gen. Meeting, Pittsburgh, July 2008, pp. 1-8. Power generation control, AC generator excitation, microgrid, diesel genset, DER. In this paper the operation of diesel engine-driven wound-field synchronous generator sets as Distributed Generators (DG’s) is studied. The objective of this work is to develop the modeling and control framework for such gensets to enable their operation in a distribution system that contains multiple DG’s including inverter-based sources. The paper presents experimental results for the interaction of conventional gensets with inverter-based sources in a microgrid test system. From the test results it is observed that there is significant circulating reactive power between the sources as well as frequency oscillations caused by the response of the conventional genset controller. A new controller for the genset is proposed that alleviates these issues and enables the various sources to share power and maintain power quality within the system. The operation of the new controller is demonstrated using simulation results. S. Krishnamurthy, T.M. Jahns, R.H. Lasseter
2008-039 039 A Fault Tolerant Doubly Fed Induction Generator Wind Turbine Using a Parallel Grid Side Rectifier and Series Grid Side Converter IEEE Transactions on Power Electronics, Special Issue on Wind Power, May 2008, Page(s): 1126 - 1135. Doubly fed induction generator (DFIG), dynamic voltage restorer, voltage sag ride-through, wind turbine. With steadily increasing wind turbine penetration, regulatory standards for grid interconnection have evolved to require that wind generation systems ride-through disturbances such as faults and support the grid during such events. Conventional modifications to the doubly fed induction generation (DFIG) architecture for providing ride-through result in compromised control of the turbine shaft and grid current during fault events. A DFIG architecture in which the grid side converter is connected in series as opposed to parallel with the grid connection has shown improved low voltage ride through but poor power processing capabilities. In this paper, a unified DFIG wind turbine architecture which employs a parallel grid side rectifier and series grid side converter is presented. The combination of these two converters enables unencumbered power processing and robust voltage disturbance ride through. A dynamic model and control structure for this architecture is developed. The operation of the system is illustrated using computer simulations. P. Flannery, G. Venkataramanan
2008-040 040 Analytical Modeling of Semiconductor Losses in Three Level Inverter for FACTS Applications Proceedings of the IEEE IECON, Orlando, FL, Nov. 2008. Power circuits used in prototype applications forflexible ac transmission systems (FACTS) have consisted of multiple three level or neutral point clamped power converters interfaced to the power system using transformer arrangements for improving waveform quality. This paper presents analytical modeling to determine semiconductor losses in such multi-pulse voltage source dc-ac converters used for FACTS applications. Device current and voltage waveforms during all operating conditions are used to develop behavioral loss models to determine power losses in each of the power semiconductors constituting an inverter pole. The results are used to determine the total power losses in an SSSC application. Computer simulation waveforms are used to demonstrate overall system performance. F. Mancilla-David, G. Venkataramanan
2008-041 041 The Status of DC Microgrid Protection Conference Record of the IEEE IAS Annual Meeting, Edmonton, Canada, Oct. 2008. AC microgrids are a convenient approach to integrating distributed energy systems with utility power systems. On the other hand, DC micro-grids can lead to more efficient integration of distributed generation. They are the preferred topology for present shipboard, aircraft and automotive power systems and hold promise for future environmentally friendly office buildings, homes, rural areas and industrial power parks. However, standards, guidelines, practical experience and cost effective implementations for DC system protection are well behind practices in AC system protection. This paper presents a comprehensive overview of the body of research on protection of DC micro-grids, presented with a goal of identifying and advancing the field. The paper presents a discussion of the current status of dc micro-grid protection, including the use of electro-mechanical circuit breakers, solid state circuit breakers, protective system design, ground fault location and fault isolation. R. Cuzner, G. Venkataramanan
2009-001 001 New Parameter-insensitive Observer-based Control Methods for Combined Source Voltage Harmonics and Unbalance Disturbances in PWM Voltage-Source Converters Proc. of IEEE APEC Conf., February 15-19, 2009, Washington DC, IEEE Trans. on Ind. Appl., Vol 45, No. 6, Nov/Dec 2009, pp. 2010-2021. Disturbance observer, power quality, pulsewidthmodulation (PWM) voltage-source converters, unbalance compensation, voltage harmonics. In this paper, computationally efficient sinusoidaldisturbance estimation and elimination methods are introduced into the control of an active front end (AFE) voltage-source converter (VSC) to achieve effective disturbance rejection in high power systems with slower pulsewidth-modulation switching frequencies (e.g., 5 kHz) and limited current-controller bandwidth. Since the active rectifier is in series with the source and the load, there is no need to add additional hardware for harmonic elimination. The input positive- and negative-sequence voltages are extracted using the new observer methods, and negativesequence currents are injected to eliminate the dc-link 120-Hz ripple. The observer-based disturbance-rejection methods are proven to be very effective when all three types of disturbances (input-voltage harmonics, unbalance, and inductor unbalance) coexist simultaneously, even under input-inductance variations of 30%. Simulation results are verified experimentally using a 15-hp adjustable-speed-drive system that includes an AFE VSC coupled to a dSpace controller. K. Lee, T.M. Jahns, T.A. Lipo, V. Blaschko, R.D. Lorenz
2009-002 002 Analysis of Shaft Voltage in a Doubly-fed Induction Generator Proc. of Int'l Conf. on Renewable Energies and Power Quality (ICREPQ'09), April 15-17, 2009, Valencia, Spain, IET Power Electronics 2010 Volume 3, Issue 3, April 2010, pp. 379-390. This study deals with the analysis of the parameters that are effective in shaft voltage generation of induction generators. It focuses on different parasitic capacitive couplings by mathematical equations, finiteelement simulations and experiments. The effects of different design parameters have been studied on proposed capacitances and resultant shaft voltage. Some parameters can change proposed capacitive coupling such as stator slot tooth, the gap between slot tooth and winding and the height of the slot tooth, as well as the air gap between the rotor and the stator. This analysis can be used in a primary stage of a generator design to reduce motor shaft voltage and to avoid additional costs of resultant bearing current mitigation. J. Adabi, F. Zare, A. Ghosh, R.D. Lorenz
2009-003 003 Sensorless Control of a Four Phase Switched Reluctance Drive Using High Frequency Signal Injection Proc. of IEEE IEMDC Conf., May 3-6, 2009, Miami. High frequency signal injection, position estimation, sensorless control, switched reluctance machine drives. This paper presents a novel position and velocity estimation technique in four-phase switched reluctance drives based on high frequency signal injection methods. To estimate rotor position and velocity, an identical high frequency carrier voltage signal is superimposed on the main phase voltages and injected into the machine. As a result, the phase currents are composed of both main excitation currents for torque production and high frequency currents for rotor position estimation. An appropriate signal processing technique is shown to extract the spatial saliency of the machine, which is used to obtain robust position estimation via a saliency-tracing observer. The impact of saturation on machine saliencies is analyzed. Modified signal injection is developed to improve the position estimation performance in saturation. Simulation and experimental results are presented to evaluate the effectiveness of the proposed method for continuous rotor position estimation over a range of low speeds and load torques. E. Kayikci, R.D. Lorenz
2009-004 004 Induction Machine Design Methodology for Self-Sensing: Balancing Saliencies and Power Conversion Properties Proc. of IEEE IEMDC Conf., May 3-6, 2009, Miami, IEEE Trans on Ind. Appl., Vol. 47, No. 1, Jan/Feb 2011 pp 79-87. Carrier rotor position saliency, carrier signal injection, induction machines (IMs), saturation saliency, self-sensing. Zero-to-low-speed flux/rotor-position self-sensing techniques rely on the interaction of saliencies (asymmetries) with an injected signal or special switching pattern in the inverter to produce a response which contains information about the location of the saliency. In this paper, three types of deterministic spatial rotor position saliencies are introduced into an induction machine (IM). The saliencies were created by modulating the following: 1) the rotor bridge opening width; 2) the rotor bridge opening height; and 3) the rotor bridge opening fill. The influence of saliency geometric design variables on the self-sensing and power conversion properties is determined using a design of experiments and response surface methodology. An example IM design, which maximizes the self-sensing properties while preserving power conversion abilities, is presented. Modulation of the rotor bridge fill appears to be the least desirable saliency type. Both rotor bridge opening width and height modulations can be used successfully, but the rotor bridge opening width modulation requires extra simulations to characterize the self-sensing properties. I.P. Brown, R.D. Lorenz
2009-005 005 Digital Implementation Issues of Electronic Line Shafting Proc. of IEEE IAS Pulp & Paper Industry Conf., June 21-25, 2009, Birmingham, AL. Digital Control, Motion Control, Motion Measurement, Motor Drives Electronic line shafting is a control methodology for reproducing the desirable inter-shaft dynamics of a physical line shaft while adding some features that cannot be achieved with a physical line shaft. There are important challenges that must be addressed before ELS can be implemented. In paper manufacturing and converting, drives sharing a common back plane can be easily clocked together so that the sampling for each drive is synchronized. However, it is difficult and expensive to synchronize every drive in every section. Asynchronous sampling between drives will cause perceived distortion which negatively affects the degree of motion and tension control available. Relative state motion control requires high position information resolution to be able to accurately measure and correct for small differences in motion between shafts. In addressing these issues, ELS can be implemented correctly to achieve much more precise tension and speed control in paper machines. C.M. Wolf, R.D. Lorenz, M.A. Valenzuela
2009-006 006 A Supersynchronous Doubly Fed Induction Generator Option for Wind Turbine Applications Proc. of Power Electronics and Machines for Wind Applications Conf., June 24-26 2009, in Lincoln, NE. Doubly fed induction generators are presently used in the large majority of high power wind turbine applications. The present technology specifies that the turbine operate subsynchronously to follow the desired power vs. wind speed profile and to operate only supersynchronously during brief periods where wind gusts exceed the nominal maximum value of thrust. This paper suggests that improved operation is possible if the generator is confined to always operate in the supersynchronous state resulting in improved efficiency, lower cost and greater output power. T.A. Lipo
2009-007 007 Small Signal Stability of a Microgrid with Parallel Connected Distributed Generation International Journal of Intelligent Automation & Soft Computing, Vol. 16, No. 2, pp. 1-20, 2009. Distributed generation, dynamic stability, microgrids Distributed Generation, or DG, involves utilization of small generators that are distributed in a power network, to supply the electric power demands of utility customers. This paper presents the small signal analysis of droop based generation control schemes for parallel connected DG inverters comprising of active powerfrequency and reactive power-voltage controllers. Small-signal models are developed for microgrids consisting of several DGs connected in a parallel configuration. Mathematical propositions that develop sufficiency conditions for stability of the system are developed. M. Illindala, G. Venkataramanan
2009-008 008 A Simplified Model of a Nine Phase Synchronous Machine Using Vector Space Decomposition IEEE Conf. on Power Electronics and Machines for Wind Applications, Proceedings of, June 24-26, 2009, Lincoln, NE. This paper describes the use of vector space decomposition for development of a simplified model of a nine phase synchronous machine. It is shown that the nine phase machine can be reduced to the usual d-q equivalent circuit model plus seven additional circuits to represent zero sequence components. These additional components are shown to provide additional current paths for both zero sequence components as well as negative sequence components. A.A. Rockhill, T.A. Lipo
2009-009 009 Economics of Future U.S. Wave Energy Markets: A Coupled Analysis of Regional Wave Climate and Energy Market Data Proc. of European Wave and Tidal Energy Conf., September 7-10, 2009, Uppsala, Sweden. North American (U.S.) Wave Power, Wave Climate, Renewables Market, Price per Meter of Wavefront This paper analyzes wave climate and energy market data to produce a regional picture of coastal U.S. wave energy market prices and wave power. Energy production capacity and market cost per kWh trends are established to show prospective energy demand and earning capability for a wave power park in each coastal region. The state data is partitioned amongst the coastal regions: north or south Pacific coast, north or south Atlantic coast, and Gulf coast. Projected earnings data per coastal region is then coupled with the seasonal wave power available in those regions, with the introduction of ‘prospective earnings per month per meter of wavefront’. The paper concludes with an economic comparison of power prices, usable wave power between coastal regions, and forecasted renewables demand. J. Vining, T.A. Lipo
2009-010 010 Autonomous Powers Electronic Interfaces Between Microgrids Proc. of IEEE Energy Conversion Congress and Exposition (ECCE), September 20-24, 2009, San Jose, CA. microgrids, voltage source converters, back-toback interface. The use of back-to-back (BTB) voltage source converters (VSCs) to interface large scale asynchronous ac power systems is well established. BTB VSCs also provide a convenient means to interface small scale microgrids and the utility power grid. The relatively small size of such interfaces and broad scale of their application would mandate autonomous fast operation based on the health of the microgrids, although their preferred operating points (set-points) may be dispatched from relatively slow supervisory systems. This paper presents a method to control such interfaces so as to preserve microgrid-like operation of each ac system and to autonomously transfer power across the interfaces. The paper describes the control architecture, analytical model, and design method that ensure robust operation. We demonstrate the design of a 2-microgrid interface using a dynamic phasor model, which we show to be more accurate than the reduced order VSC model commonly used in microgrid analyses. The interface can also alter the steady state power flow between microgrids to suit energy management strategies in a smart grid. Finally, we present simulation and experimental test results of the interface operation. S. Bala, G. Venkataramanan
2009-011 011 Design and Optimization of a Novel Hybrid Transverse / Longitudinal Flux, Wound-Field Linear Machine for Ocean Wave Energy Conversion Proc. of IEEE Energy Conversion Congress and Exposition (ECCE), September 20-24, 2009, San Jose, CA. ocean wave energy; wound-field linear asynchronous generator; linear machine design; FEA optimization This paper develops an analytical model for a novel double-sided hybrid transverse / longitudinal flux linear machine for use in ocean wave energy converter (WEC) applications. While several machine topologies exist for direct-drive power take-off in buoy-type WECs, the intent of this paper is to introduce a new type of linear machine for possible use as a direct-drive in future WECs. The topology considered consists of a short primary (stator) and a long secondary (translator). The translator is sandwiched between two stators that carry flux in the longitudinal direction, while the translator carries flux in the transverse direction. Operating conditions for WECs require low speeds, yielding machine characteristics such as a large number of coil turns, high inductance, and high force density. Finite element analysis (FEA) is used to optimize and validate analytical results as well as calculate leakage and magnetizing inductance. J. Vining, T.A. Lipo, G. Venkataramanan
2009-012 012 Grid-fault Tolerant DFIG Wind Turbine Generator Using a Passive Resistance Network, Proc. of IEEE Energy Conversion Congress and Exposition (ECCE), September 20-24, 2009, San Jose, CA. voltage sag, low voltage ride through, doubly fed induction generation (DFIG), wind turbine. x With increasing penetration of wind turbines in the utility grid, new regulation codes have been issued that require them to have low voltage ride-through capability. In this paper, a passive resistive network, consisting of shunt and series elements are applied at the stator side of DFIG wind turbine is presented. The network is inactive during steady state operation and enabled for short intervals of time during the initiation of voltage sag and recovery events. Computer simulation and experimental results confirming the operation during balanced and unbalanced voltage sags are shown in the paper. X. Yan, G. Venkataramanan, Y. Wang
2009-013 013 Segregation of Torque Components in Fractional-Slot Concentrated Winding Interior PM Machines Using Frozen Permeability Proc. of IEEE Energy Conversion Congress and Exposition, September 20-24, 2009, San Jose, CA. Frozen permeability, permanent magnet synchronous machines, fractional slot concentrated windings, reluctance torque, permeances, magnetic circuit model Torque is produced in interior permanent magnet (IPM) machines as a result of stator current interactions with the rotor permanent magnets and rotor electromagnetic reluctance. Separation of the torque into its permanent magnet (PM) and reluctance components is helpful to machine designers but is complicated by the nonlinearity of magnetic saturation. This paper proposes a magnetic circuit model (MCM) to predict machine characteristics under frozen permeance conditions to help segregate machine torque components into PM and reluctance torques. Strengths and limitations of previously proposed techniques for performing this torque segregation are compared, including techniques based on finite element (FE) analysis. An alternative technique is proposed for delivering torque segregation results for fractional-slot concentratedwinding (FSCW) IPM machines that compares very well with the FE frozen permeability results but with significantly faster computation time. FE analysis is used to compare the characteristics of four alternative torque segregation techniques. J.K. Tangudu, T.M. Jahns, A. El-Refaie, Z.Q. Zhu
2009-014 014 Modeling of Stator Teeth-Tip Iron Losses in Fractional-Slot Concentrated Winding Surface PM Machines Proc. of IEEE Energy Conversion Congress and Exposition, September 20-24, 2009, San Jose, CA. iron losses, surface permanent magnet machines, high speed operation, tooth tips, conformal mapping. This paper presents a model for estimating the iron losses in the stator teeth tips of surface permanent magnet (SPM) machines with fractional-slot concentrated windings based on simplified semi-analytical solutions for the machine flux densities. This model is being developed for use in machine design optimization software that analyzes very large numbers of candidate designs. Tooth tip design details are important because a significant fraction of the total stator iron losses is concentrated in these structures during high-speed operation. The first model in this paper focuses on closed-form solutions for no-load operation. It is shown that the simplified model can estimate the stator losses predicted by finite element (FE) analysis within 15% while consuming less than 0.1% of the calculation time required for FE analysis. Armature reaction is included by means of conformal mapping analysis that makes it possible to predict the tooth-tip losses during loaded operation within 15% of the FE results. P.B. Reddy, T.M. Jahns
2009-015 015 Lumped Parameter Magnetic Circuit Model for Fractional-Slot Concentrated-Winding Interior Permanent Magnet Machines Proc. of IEEE Energy Conversion Congress and Exposition, September 20-24, 2009, San Jose, CA Electric machines, magnetic circuits, permanent magnet machines, fractional slot concentrated winding, cross-coupled permeances. This paper presents a simplified lumpedparameter magnetic circuit model (MCM) of a fractional-slot concentrated-winding (FSCW) interior permanent magnet (IPM) machine that provides rapid estimates of machine performance for use in machine design optimization software. This model incorporates several key nonlinear phenomena including (i) magnetic saturation; (ii) cross-saturation effects between the d- and q-axes affecting both flux linkages and inductances; (iii) stator slotting effects; and (iv) localized effects due to rotor bridges. A coupled permeance element is proposed that captures the cross-coupling saturation effects along with airgap modeling that captures both radial and tangential airgap flux densities. The MCM is configured to predict key machine performance variables including airgap flux densities, backEMF, phase and dq-axis inductances, characteristic current, and torque. Finite element (FE) analysis results are presented that match the MCM results quite closely, building confidence in the MCM model. J.K. Tangudu, T.M. Jahns, A. El-Refaie, Z.Q. Zhu
2009-016 016 Transposition Effects on Bundle Proximity Losses in High-Speed PM Machines Proc. of IEEE Energy Conversion Congress and Exposition, September 20-24, 2009, San Jose, CA. AC losses, high-speed PM machines, proximity loss, bundle proximity effects, circulating currents, slot effects, 3-D effects, transposition effects. Proximity effects caused by uneven distribution of current among the insulated wire strands of stator multi-strand windings can contribute significant bundle-level proximity losses in permanent magnet (PM) machines operating at high speeds. Three-dimensional finite element analysis is used to investigate the effects of transposition of the insulated strands in stator winding bundles on the copper losses in high-speed machines. The investigation confirms that the bundle proximity losses must be considered in the design of stator windings for high-speed machines, and the amplitude of these losses decreases monotonically as the level of transposition is increased from untransposed to fully-transposed (360°) wire bundles. Analytical models are introduced to estimate the currents in strands in a slot for a high-speed machine. P.B. Reddy, T.M. Jahns, T.P. Bohn
2009-017 017 Stator Side Voltage Regulation of Permanent Magnet Generators Proc. of Society of Automotive Engineers, November 10-12, 2009, Seattle, WA. Permanent magnet AC generators are robust, inexpensive, and efficient compared to wound-field synchronous generators with brushless exciters. Their application in variable-speed applications is made difficult by the variation of the stator voltage with shaft speed. This paper presents the use of stator-side reactive power injection as a means of regulating the stator voltage. Design-oriented analysis of machine performance for this mode of operation identifies an appropriate level of machine saliency that enables excellent terminal voltage regulation over a specified speed and load range, while minimizing stator current requirements. This paper demonstrates that the incorporation of saliency into the permanent magnet generator can significantly reduce the size of the reactive current source that is required to regulate the stator voltage during operation over a wide range of speeds and loads. N.C. Clements, G. Venkataramanan, T.M. Jahns
2009-018 018 Hierarchical Control of Bridge of Bridge Multilevel Power Converters. IEEE Transactions on Industrial Electronics 2009. Multilevel converters are among the family of power converter topologies for realizing higher power levels and better waveform quality. In addition to established topologies of the neutral point clamped three level converter and cascaded Hbridge converters, novel topologies thatoffer attractive features such as ease of modularity and functionality continue to be introduced. Among these, the Bridge-of-Bridge multilevel converters have the potential for realizing multi-megawatt systems with ease. This paper is aimed at presenting a systematic approach to developing their dynamic and steady state models, leading to a hierarchical control approach that is intuitive to realize and versatile in application. The paper presents the dynamic model, steady state model, and computer simulations that demonstrate the approach in dc-1 /ac and 3 /ac-3 /ac power conversion applications. Experimental validation of the models using a dc-1 /ac asymmetric half bridge converter is presented. D.C. Ludois, J. Reed, G. Venkataramanan
2009-019 019 Evaluating the Practical Low Speed Limits for Back-emf Tracking-Based Sensorless Speed Control Using Drive Stiffness as the Metric Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), Sept. 20-24, 2009, San Jose, CA, IEEE Trans. on Ind. Appl., Vol 47, No.3. May/June 2011 pp. 1337-1343. Back electromotive force (back EMF), back-EMF harmonics, permanent-magnet synchronous machine (PMSM), self-sensing, sensorless. Although it is widely known that backelectromotive-force tracking has a low-speed limit, there is very little published literature evaluating this limit. This paper shows that the low-speed limit is mainly a function of the amplitude of the inverter harmonics and that theory and simulation will provide erroneous results when inverter harmonics are not incorporated. This paper will also provide a method for evaluating this low-speed limit using drive stiffness as the metric. The experimental results show quantitatively how the drive stiffness suffers as speed decreases, which ultimately sets the practical low-speed limit. R.W. Hejny, R.D. Lorenz
2009-020 020 Self-sensing Comparison of Fractional Slot Pitch Winding vs. Distributed Winding for IPMSM and FI-IPMSM Based On Carrier Signal Injection at Very Low Speed Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), Sept. 20-24, 2009, San Jose, CA, IEEE Trans. on Ind. Appl., Vol 46, No.6, Nov/Dec 2010 pp 2467 - 2474. Carriersignalinjection, distributedwinding, fluxintensified permanent-magnet synchronous machines (PMSMs), fractional slot pitch winding, saturation effects, self-sensing. This paper analyzes the effects of fractional pitch and distributed winding stators on the self-sensing performance of permanent-magnet machines. Three rotor configurations (i.e., a flux-weakened interior permanent-magnet synchronous machine (IPMSM) and two flux-intensified IPMSMs) and two stator designs (i.e., distributed and concentrated windings) are presented to analyze the cross saturation, secondary saliencies, saturationinduced saliencies, and saliency ratio, depending on the possible rotor and stator configurations. Finite-element modeling has been used to obtain a detailed understanding of the self-sensing performance of these machines. D. Reigosa, K. Akatsu, N. Limsuwan, Y. Shibukawa, R.D. Lorenz
2009-021 021 Observer Based Inverter Disturbance Compensation Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), September 20-24, 2009, San Jose, CA. Induction motor, Inverter disturbance, Disturbance observer, High-frequency injection, DC offset. Most inverter disturbance compensation methods are based on open-loop inverter disturbance estimation. Because of measurement error and switching device parameter uncertainties, the inverter disturbance is not always compensated well. This paper proposes a closed-loop voltage disturbance observer and an observer-based inverter disturbance compensation method to improve the compensation. The performance and limits of the voltage disturbance observer and compensation system are analyzed in detail. Analytical and experimental results are provided to verify the performance. The results are particularly relevant when the inverter is used to inject signals for self-sensing. X. Yuan, I.P. Brown, R.D. Lorenz, A. Qui
2009-022 022 Gear fault diagnostics integrated in the motion servo for electromechanical actuators Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), Sept. 20-24, 2009, San Jose, CA. IEEE Trans. on Ind. Appl., Vol 48, No. 1, Jan/Feb 2012 pp. 140-150. Gear fault diagnostics, kinematic error estimation, motion servo drive, spatial domain sampling, synchronous averaging. This paper presents contributions made in gear fault diagnostics for motion servos with continuously variable speed as used for aerospace and automotive electromechanical actuators. As the first step for motion servo diagnostics, an observer-based kinematic error estimator is developed whereby this estimated kinematic error is proposed as an operating pointindependent gear surface fault signature. As the second step, a signal processing method is developed for real-time implementation of spatial domain resampling of regular time domain samples, and this method is combined with spatial domain synchronous averaging methods, which are shown to be very effective in filtering out unwanted asynchronous signatures. Lastly, a motion servo actuator with a gear surface failure is tested, and the proposed methods are shown to successfully extract the kinematic error profiles of the defective gear during motion servo operation over a wide range of continuously varying velocity. K.K. Huh, R.D. Lorenz, N.J. Nagel
2009-023 023 Discrete-time Current Regulator Design for AC Electric Machine Drives Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), Sept. 20-24, 2009, San Jose, CA, IEEE Trans. on Ind. Appl., Vol. 46, No. 4, Jul/Aug 2010 pp. 1425-1435. Complex vector current regulator design, digital delay, discrete-time complex vector current regulator design, ratio of fundamental-to-sampling frequencies. This paper analyzes the behavior of discrete-time current regulators for ac machines operating at high ratios of fundamental-to-sampling frequencies, a situation common for high-speed automotive drives and large-traction drives. At high ratios of fundamental-to-sampling frequencies, highly oscillatory, or unstable, response can occur if the current regulator design does not properly incorporate the effects of the discrete nature of the controller, including delays between the sampling of signals and the application of the voltage commands through pulse-width modulation (PWM). This paper investigates these issues for different design methods and current regulator topologies. As part of this investigation, a simple discrete-time domain ac machine model is developed that includes the delays associated with PWM. This model is then used to design a discrete-time domain version of the complex vector PI current regulator that demonstrates improved response compared with the other regulators studied. Simulation and experimental results are provided to compare the performance, stability, and robustness of the current regulators analyzed. H. Kim, M. Degner, F. Briz
2009-024 024 Dead-beat Direct Torque and Flux Control of Interior Permanent Magnet Machines with Discrete Time Stator Current and Stator Flux Linkage Observer Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), Sept. 20-24, 2009, San Jose, CA and IEEE Trans. on Ind. Appl., Vol. 47, No. 4, Jul/Aug 2011 pp. 1749-1758. Current and flux linkage observer, deadbeat control, direct torque control (DTC), interior permanent magnet machine. This paper presents a discrete time deadbeat-direct torque and flux controller (DB-DTFC) for interior permanent magnet synchronous machines (IPMSMs). A Gopinath-style discrete time flux linkage observer is developed which contains two different flux estimation methods based on current and voltage models for flux linkage. This observer produces correctly estimated flux linkages needed for accurate DB-DTFC implementation. In order to eliminate the sampling delay due to a characteristic of digital control computation, a complex vector model-based rotor reference frame current observer is also developed. Combining the discrete time current and flux linkage observers, the correct single time step (deadbeat) air-gap torque and stator flux linkage control at the (constant) switching frequency is achieved and experimentally evaluated. J.S. Lee, C.H. Choi, J.K. Seok, R.D. Lorenz
2009-025 025 Modeling the 3D Rotational and Translational Motion of Magnets Over a Conducting Guideway Using a Combined Field and Lumped-Parameter Model IEEE Transactions on Magnetics, Vol. 45, No. 9, Sept. 2009, pp. 3233-3242. Biot–Savart law, convective, diffusive, eddy currents, finite-element method, Halbach rotor, maglev When a Halbach rotor is simultaneously rotated and translationally moved above a split-sheet aluminum guideway a traveling timevarying magnetic field is created in the air gap. This field induces eddy currents in the guideway that can simultaneously create suspension and propulsion forces. If the rotor is offset from the center then a re-centering guidance force can also be created. As the forces are created in a highly inductive way the use of magnets circumvents any low power factor issues and enables a relatively high lift-to-weight ratio to be attained in comparison to using windings. The conductive and nonconductive regions are modeled by using a steady-state convective A- formulation. The Halbach rotor is modeled using a 3-D analytic based model and is coupled to the conductive guideway region using boundary conditions. The steady-state rotation of the Halbach rotor is modeled by incorporating complex terms in the analytic model. The accuracy of the steady-state model is confirmed by comparing it with a 3-D transient ?nite-element Magsoft Flux model (with no translation) and with experimental results (with both rotation and translation). The effect of the rotor width on performance is also investigated. J. Bird, T.A. Lipo
2009-026 026 The Role of Plug-In Hybrid Electric Vehicles in Demand Response and Beyond IEEE PES T&D Conference & Exposition, April 20-22, 2010, New Orleans, LA. Dispersed storage and generation, Load management, Power system economics, Power system reliability, Utility programs, Electric vehicles As the electric utility industry continues to move towards becoming more of a deregulated entity, demand response programs are playing a much larger role. Plug-in hybrid electric vehicles (PHEVs) have the potential to increase the ability of residential customers to participate in demand response programs. However, there may need to be changes made in order to incorporate the spatially mobile aspect of PHEVs as new charging infrastructure enables vehicles to charge in many locations. New demand response programs may also be needed to take advantage of the storage potential inherent in the batteries of PHEVs. This paper explores the potential impact of PHEV market penetration on demand response in order to outline the most effective manner of using these resources. M. Mallette, G. Venkataramanan
2009-027 027 Motor Integrated Permanent Magnet Gear with a Wide Torque-Speed Range Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), September 20-24, 2009, San Jose, CA. Permanent magnets, magnetic gear, integration, electrical vehicle, traction, FEA, direct drive. This paper present a new motor integrated permanent magnet gear with a wide torque-speed range. In the paper a 35 kW permanent magnet motor with a base speed of 4000 rpm and a top speed of 14000 rpm is integrated into a permanent magnetic gear with a gearing ratio of 8.67. The design process of the combined unit is described together with a description of the construction of the part for a test model. The unit is unique in the sense that it has superior traction characteristics and a torque density of 130 Nm/l which is more 1.5 times of other reported motor integrated permanent magnet gears. The unit may be useful as a direct drive wheel motor for EV’s and no liquid cooling system is required. P.O. Rasmussen, H.H. MOrtensen, T.N. Matzen, T.M. Jahns, H.A. Toliyat
2009-028 028 Design Considerations for a Stator Side Voltage Regulated Permanent Magnet AC Generator Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), September 20-24, 2009, San Jose, CA. AC generators, aircraft power systems, interior permanent magnet synchronous machines The application of permanent magnet generators in variable-speed applications is made difficult by the lack of a direct field control and the variation of the stator voltage with shaft speed and also with load. This paper presents the use of reactive power injection into the stator as a means of regulating the stator voltage. Design-oriented analysis of the machine stator current and reactive power requirements for this mode of operation leads to the conclusion that high machine saliency enables excellent terminal voltage regulation over a specified speed and load range while minimizing stator current requirements. It is shown that the incorporation of saliency into the permanent magnet generator can significantly reduce the size of the reactive current source and the stator current that is required to regulate the stator voltage during operation over a broad range of speeds and loads. Experimental results are presented to confirm the basic principles of this approach. N. Clements, G. Venkataramanan, T.M. Jahns
2009-029 029 Inverse-Saliency PM Motor Performance under Vector Control Operation Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2009), September 20-24, 2009, San Jose, CA. AC generators, aircraft power systems, interior permanent magnet synchronous machines The application of permanent magnet generators in variable-speed applications is made difficult by the lack of a direct field control and the variation of the stator voltage with shaft speed and also with load. This paper presents the use of reactive power injection into the stator as a means of regulating the stator voltage. Design-oriented analysis of the machine stator current and reactive power requirements for this mode of operation leads to the conclusion that high machine saliency enables excellent terminal voltage regulation over a specified speed and load range while minimizing stator current requirements. It is shown that the incorporation of saliency into the permanent magnet generator can significantly reduce the size of the reactive current source and the stator current that is required to regulate the stator voltage during operation over a broad range of speeds and loads. Experimental results are presented to confirm the basic principles of this approach. R.H. Moncada, J.A. Tapia, T.M. Jahns
2009-030 030 Robustness Evaluation of Deadbeat, Direct Torque and Flux Control for Induction Machine Drives Proc. of EPE 2009, Sept. 8-10, 2009, Barcelona, Spain. Control of drives, direct torque and flux control, highly dynamic drive, induction motor, robustness. Field oriented control methodologies are one of the dominant industry standards for induction machine drives. While this classical approach has continuously improved, direct torque control (DTC) has emerged as an alternative approach. Deadbeat, direct torque and flux control (DB-DTFC) is a more recent scheme and employs a discrete-time model inversion to achieve decoupled control of both torque and flux with a one PWM period response time. From z-transform-based deadbeat control design theory, it is known that incorrectly estimated system parameters can lead to forced oscillations. Therefore, it was the goal of this research to rigorously evaluate the robustness of DB-DTFC and to investigate if its advantageous properties are maintained under perturbed operating conditions. An indepth analysis first isolates the observer’s influence from the control law’s sensitivity to detuned parameters at critical operating points. An enhanced flux estimation accuracy model is derived and analyzed numerically. Then, sets of a comprehensive collection of experiments are used to evaluate DB-DTFC’s robustness in comparison to the de facto standard of indirect field oriented control. It is shown that the main contributor to decreased robustness is the flux estimation algorithm – not the DBDTFC controller itself. The experimental results demonstrate nearly ideal deadbeat control performance and a high level of robustness compared to other control methodologies. B. Heinbokel, R.D. Lorenz
2009-031 031 Low voltage ride through for DFIG wind turbines using passive impedance networks Proc. of the Intl. Conf. on Sustainable Power Generation & Supply, 2009. SUPERGEN '09 EPE Journal, Vol 20. No. 3, Sept. 2010, pp. 48-57. doubly fed induction generator (DFIG), dynamic voltage recovery, voltage sag ride-through, wind turbine. This paper presents an approach to utilize a passive impedance network in series at the stator side of a typical DFIGwind turbine for the purpose of voltage sag ride through. A control strategy that enables the passive impedance network to engage and stabilize the stator flux during grid voltage sag events has been studied. Simulation results demonstrates that electromagnetic torque and rotor current meet the requirements of new regulator codes, even at zero voltage remaining with uninterrupted current feeding into the grid. Due to its topology and control strategy, the proposed system is easy to control, capable of off-line operation for high efficiency and economic in manufacturing and maintenance. X. Yan, G. Venkataramanan, P.S. Flannery, Y. Wang, Q. Dong
2010-001 001 Plug-in Electric Vehicle Interactions with a Small Office building: An Economic Analysis using DER-CAM Proc. of IEEE Power Engineering Society General Meeting, Minneapolis, July 2010. M. Marnay, M. Stadler, J. Lai, V. Battaglia, G. Venkataramanan, T. Gomez, I. Momber, S. Beer
2010-002 002 Circuit Modeling Methodology for Isolated, High Bandwidth Junction Temperature Estimation Proc. of International Power Electronics Conference (IPEC2010), June 21-24, 2010, Sapporo, Japan. EMI, Modeling, and Reliability High bandwidth junction temperature measurement provides a key signal for active thermal control to improve reliability of power electronics. Recently developed isolated techniques to estimate junction temperature from the decay of turn-on ringing depending on circuit properties are not well documented in existing circuit models. This paper focuses on how to develop circuit models that are suitable for high bandwidth estimation using the decay of turn-on ringing. The novelty of this paper is in how it models those parasitic effects that enable prediction of the decay of the output ringing waveform. Similar modeling techniques can be used to capture EMI characteristics. Modeling results focus on parasitic effects of MOSFETs and passive components in a boost converter. Simulation and experimental results are compared to validate the methodology. M.L. Walters, R.D. Lorenz
2010-003 003 Condensate Effects on Power Requirements During the Starting of Dryer Sections Proc. of IEEE IAS Pulp and Paper Industry Conf., June 21-23, 2010, San Antonio TX. IEEE Trans. on Ind. Appl., Vol. 47, No. 4, Jul/Aug 2011 pp. 1612-1623 dryer cylinders, condensate, power requirements, spoiler bars, dryer section starting The presence of condensate inside the dryer cylinders results in a significant increase in the power and torque required until the condensate transitions to the rimming stage. This paper evaluates the effect of the condensate during the starting of a dryer section using the experimental curves reported by several authors, as well as using a dimensionless model of the input power as a function of the condensate quantity and roll velocity. Through the evaluation of a 9-cylinder dryer section for various condensate quantities and varying number of cylinders containing condensate, a comparison is made to the power requirements of several actual paper machine dryer sections undergoing various starting procedures. These comparisons indicate that if the % condensate (condensate volume/full cylinder volume x 100) in the range of 0.5% to 1%, or greater, is nominally assumed to be present, then the sizing of the section drive capacity must take into consideration the additional indrive load resulting from this condensate. Options are proposed to consider the effect of the condensate without increasing the TAPPI rated drive capacity (RDC) of dryer sections. M.A. Valenzuela, J.M. Bentley, R.D. Lorenz
2010-004 004 Self-Sensing Methods Extended to Four Phase Switched Reluctance Machines Proc. of International Power Electronics Conference (IPEC2010), June 21-24, 2010, Sapporo, Japan. This paper presents novel high-frequency signal injection-based self-sensing methods for four-phase switched reluctance machines. The methods cover full magnetic operating range of the drive including saturation and show compensation methods to improve the rotor position estimation under saturation. The effects of magnetic saturation on machine saliencies are studied and modified carrier signal injection methods are developed to mitigate the effect of saturation on rotor position estimation. Simulation and experimental results are presented to demonstrate the effectives of the proposed method for continuous rotor position estimation at low speeds. E. Kayikci, Lorenz R.D.
2010-005 005 State Space Decoupling Approach for Feedback Controller Design of Switching Converters Proc. of International Power Electronics Conference (IPEC2010), June 21-24, 2010, Sapporo, Japan DC-DC converter, K-factor design, State Space Control, Voltage Controllers. This paper derives a new approach for analyzing dc-dc converters for feedback control design. The control-to-output voltage transfer function of the converters, usually predicted by averaging models, and the classical feedback control techniques are replaced by the state space average state block diagram analysis. These state block diagrams are obtained for state space averaging matrixes of the converters combined with their continuous conduction mode differential equations. This technique yields first order control transfer functions allowing easier synthesis of controllers. The resulting controllers demonstrate good transient response compared to voltage controllers based on k-factor approach. The structure is easy implement with relevant applications in integrated circuit manufacturing and industrial environment. E.C. Gomes, L.A.R. Souza, S. Catunda, R.D. Lorenz, J.V. Caracas
2010-006 006 Torque Ripple Reduction in Interior Permanent Magnet Synchronous Machines using Stators with Odd Number of Slots per Pole Pair IEEE Trans. on Energy Conversion, Vol. 25, Jan. 2010, pp. 118-127. interior permanent magnet (IPM) synchronous machines; odd number of stator slots per pole pair; stator slot harmonics; torque ripple This paper develops analytical principles for torque ripple reduction in interior permanent magnet (IPM)synchronous machines. The significance of slot harmonics and the benefits of stators with odd number of slots per pole pair arehighlighted. Based on these valuable analytical insights, this paper proposes coordination of the selection of stators with odd number of slots per pole pair and IPM rotors with multiple layers of flux barriers in order to reduce torque ripple. The effectiveness of using stators with odd number of slots per pole pair in reducing torque ripple is validated by applying a finiteelement based Monte-Carlo optimization method to four IPM machine topologies which are combinations of two stator topologies (even or odd number of slots per pole pair) and two IPM rotor topologies (one or two-layer). It is demonstrated that the torque ripple can be reduced to less than 5% by selecting a stator with an odd number of slots per pole pair and the IPM rotor with optimized barrier configurations, without using stator/rotor skewing or rotor pole shaping. S-H Han, T.M. Jahns, W.L. Soong, M.K. Guven, M.S. Illindala
2010-007 007 Analysis of Negative-Saliency Permanent-Magnet Machines IEEE Trans. on Industrial Electronics, Vol. 57, Jan. 2010, pp. 122-127. Axial-flux machines, flux control, flux weakening (FW), inverse saliency, maximum torque per amp (MTPA), permanent-magnet (PM) machines, PM motors, vector control. In this paper, a negative-saliency permanent-magnet (PM) synchronous machine analysis is presented. This particular saliency feature is achieved by replacing a portion of the magnet material by a soft iron piece over the rotor pole. In this manner, the d-axis inductance is increased, whereas the q-axis inductance is almost not affected, leading to the condition that Ld is higher than Lq (negative saliency) corresponding to the inverse condition of typical PM machines. An expression for the optimum pole configuration is derived. It is shown that, with appropriate control of the stator current based on the machine’s saliency, the unfavorable effects of magnet reduction on torque production can be compensated. It is also shown that the machine saliency affects the location of the operating points when it operates under vector control. Finally, the theoretical analysis is validated with experimental results obtained from a prototype axial-flux PM machine that exhibits negative saliency. R.H. Moncada, J.A. Tapia, T.M. Jahns
2010-008 008 Analysis of Bundle Proximity Losses in High-Speed Machines Proc. of 2010 International Power Electronics Conf. (IPEC'10), June 21-24, 2010, Tokyo, Japan. AC losses, brushless machines, high speed, ac machines, proximity losses, bundle losses, high efficiency. Elevated frequencies in high-speed ac machines increase the skin effect in stator windings, making it necessary in many cases to divide each phase winding into high numbers of small-diameter strands connected in parallel. Unfortunately, circulating currents among the strands in a single bundle can significantly increase the total copper losses depending on several factors including the twisting (i.e., transposition) of the strands in the bundles. An analytical model for these bundle proximity losses is presented for individual bundles as well as slot-bound bundles configured for high-speed machines. Loss predictions provided by this model match well with finite element results for high-speed operation of a 55 kW (peak) PM machine with concentrated windings. Stators with litz and non-transposed windings are compared to highlight the large differences in their bundle proximity losses. Analytical and finite element results are shown to match well with experimental results at frequencies of 700 and 800 Hz. P.B. Patel, T.M. Jahns
2010-009 009 Design Tradeoffs Between Stator Core Loss and Torque Ripple in IPM Machines IEEE Trans. on Industry Appl., Vol. 46, Jan/Feb 2010, pp. 187-195. Flux weakening, interior permanent-magnet (IPM) machines, magnet layers, stator core losses, stator slotsper-pole-pair, torque ripple. High stator core losses can pose a significant problem in interior permanent-magnet (IPM) machines operating over wide constant-power speed ranges. At lower speeds, the torque ripple can be undesirably large in some IPM machine designs, contributing to acoustic noise and vibration. While previous work has addressed these two problems independently, this paper shows that the conditions for reducing stator core losses during flux-weakening operation, dominated by harmonic eddy-current losses in the stator teeth, can conflict with the conditions for reducing the torque ripple of IPM machines. It is also shown that the resulting design tradeoffs depend on the details of the IPM machine topologies that are under consideration. The appropriate IPM machine topologies that offer more favorable tradeoffs are identified to achieve the best possible compromise of high-speed stator core losses and torque ripple characteristics. S.-H. Han, T.M. Jahns, Z.Q. Zhu
2010-010 010 Analysis of Rotor Core Eddy-Current Losses in Interior Permanent-Magnet Synchronous Machines IEEE Trans. on Ind. Appl., Vol. 46, Jan/Feb 2010, pp. 196-205. Concentrated- and distributed-winding stators, interior permanent-magnet (IPM) machines, one- and two-layer rotors, rotor core eddy-current losses. This paper presents the results of an investigation focused on the rotor core eddy-current losses of interior permanentmagnet (IPM) synchronous machines. First, analytical insight into the rotor core eddy-current losses of IPM machines is developed. Next, major design parameters that have the most significant impact on the rotor core eddy-current losses of IPM machines are identified. Finite-element analysis results are then presented to compare the predicted eddy-current losses in the machine core of IPM machines with one- and two-layer rotors coupled with concentrated- and distributed-winding stators. It is shown that the lowest total eddy-current losses in the machine core are achieved using a combination of distributed stator windings and two magnet layers per rotor pole, whereas minimizing only the rotor core eddy-current losses favors replacement of the rotor with a single-layer configuration. S.-H. Han, T.M. Jahns, Z.Q. Zhu
2010-011 011 Reducing Harmonic Eddy-Current Losses in the Stator Teeth of Interior Permanent Magnet Synchronous Machines During Flux Weakening IEEE Trans. on Evergy Conversion, Vol. 25, June 2010, pp. 441-449. Core losses, flux-weakening operation, harmonic eddy-current losses, high speed, Interior permanent magnet (IPM) machines, two-layer rotor. Interior permanent magnet (IPM) synchronous machines can experience large harmonic eddy-current losses in the stator teeth under flux-weakening operation, significantly depressing the efficiency of these machines at high operating speeds. This paper presents a new analytical/finite-element hybrid design approach to reduce the harmonic eddy current losses in IPM machine stator teeth during flux-weakening operation. The proposed technique achieves this objective by three steps: 1) developing an analytical index for the harmonic eddy-current losses in IPM machine stator teeth; 2) designing the spatial distribution of the rotor MMF to minimize the analytical index; and 3) synthesizing the rotor geometry to implement the desired rotor MMF function while maintaining the basic machine characteristics unchanged. It will be shown that two-layer rotors, if properly optimized, are significantly more effective than one-layer rotors for the purpose of reducing the harmonic eddy-current losses in IPM machine stator teeth during flux-weakening operation at high speeds. S.-H. Han, W.L. Soong, T.M. Jahns, M.K. Guven, M.S. Illindala
2010-012 012 Financial Incentives to Encourage Demand Response Participation by Plug-In Hybrid Electric Vehicle Owners ECCE2010 conference. Dispersed storage and generation, Load management, Power system economics, Power system reliability, Utility programs, Electric Vehicles Demand response has the potential to increase the flexibility and reliability of the bulk electric system. Although the majority of demand response is currently provided by the industrial and commercial sectors, the residential sector has the potential to ultimately provide more demand response than any other sector. Plug-in hybrid electric vehicles (PHEVs) further increase the ability of residential customers to participate in demand response programs and help to offset any negative impacts that may stem from PHEV charging. This paper will explore the financial incentives necessary to encourage PHEV owners to participate in demand response programs using a case study based on existing time-of-use rates in the Madison Gas & Electric service territory. M. Mallette, G. Venkataramanan
2010-013 013 Power Conversion Coursework Using a Solid State Tesla Coil Proc. 2010 ASEE Annual Conference, June 20-23, 2010, Louisville, KY. J. Reed, D. Ludois, M. Hamlin
2010-014 014 Modeling Power Semiconductor Losses in HEV Powertrains using Si and SiC Devices Proc. 2010 IEEE Vehicle Power and Propulsion Conference (VPPC), Sept. 1-3, 2010, Lille, France. Silicon carbide; ac-dc power conversion; power electronics; propulsion. Silicon carbide (SiC) power semiconductor devices are known to have potential benefits over conventional silicon (Si) devices, particularly in high power applications such as hybrid electric vehicles (HEVs). Recent literature studying the use of SiC JFETs in HEV inverters indicate a substantially increased gas mileage. This paper further investigates this change in inverter efficiency due to the adoption of SiC using analytical loss models and empirical loss data obtained from experimental Cree 1200V 10A DMOSFETs and Schottky diodes. A motor inverter efficiency map is developed and used in the VEHLIB simulator to evaluate fuel consumption benefits. Distribution of conduction and switching losses in both Si and SiC inverters is explored. J. K. Reed, J. McFarland, J. Tangudu, E. Vinot, R. Trigui, G. Venkataramanan, S. Gupta, T. Jahns
2010-015 015 System Identification-Based Lead-Acid Battery Online Monitoring System for Electric Vehicles 2010 IEEE Energy conversion Congress & Expo (ECCE ‘10) State-of-Charge (SOC), State-of-Health (SOH), State-of-Function (SOF), Electric Vehicle (EV), Battery Management System (BMS), Lead-Acid Battery. A system identification-based model for the online monitoring of batteries for electric vehicles (EVs) is presented. This algorithm uses a combination of battery voltage and current measurements plus battery data sheet information to implement model-based estimation of the stored energy, also referred to as state-of-charge (SOC), and power capability, also referred to as state-of-function (SOF), for deep-cycle batteries. This online monitoring scheme has been implemented for a bank of deep-cycle lead-acid batteries and experimental laboratory tests using simulated driving cycles have yielded promising results. In addition, actual road data from an EV powered by these same batteries has been analyzed with the proposed model to demonstrate the system’s usefulness in determining the battery state-of-health (SOH). Finally, the limitation of the use of a linear model for battery terminal voltage behavior is discussed. L.W. Juang, P.J. Kollmeyer, T.M. Jahns, R.D. Lorenz
2010-016 016 Core Loss Prediction Using Magnetic Circuit Model for Fractional- Slot Concentrated-Winding Interior Permanent Magnet Machines 2010 IEEE Energy conversion Congress & Expo (ECCE ‘10) Electric machines, magnetic circuits, permanent magnet machines, fractional slot concentrated winding, iron losses, core loss modeling. This paper presents a promising technique for estimating the cores losses of a fractional-slot concentratedwinding (FSCW) interior permanent magnet (IPM) machine using a simplified lumped-parameter magnetic circuit model (MCM). This model incorporates several key nonlinear phenomena including (i) magnetic saturation; (ii) crosssaturation effects between the d- and q-axesaffecting both flux linkages and inductances; (iii) stator slotting effects; and (iv) localized effects due to rotor bridges. The MCM is configured to predict the flux densities waveforms in the iron as the rotor rotates. Fourier transformation is then applied to extract the frequency components of the flux density in each iron core permeance element, followed by estimation of the losses in each element. These permeance losses can then be combined to provide the estimated iron losses in the total core. Very good agreement is demonstrated between core loss predictions delivered by this model for a target FSCW-IPM machine and those provided by finite element (FE) analysis. J.K. Tangudu, T.M. Jahns, A. El-Refaie
2010-017 017 Design, Analysis and Fabrication of a High-Performance Fractional-Slot Concentrated Winding Surface PM Machine 2010 IEEE Energy conversion Congress & Expo (ECCE ‘10) AC losses, brushless machines, high speed, surface permanent magnet synchronous machine, proximity losses. A high-performance 55 kW (peak) fractional-slot concentrated winding (FSCW) surface permanent magnet (SPM) machine has been designed to meet demanding performance requirements based on the FreedomCar advanced traction motor requirements prepared by the US Department of Energy. This paper describes key steps in the design, analysis, fabrication, and testing of this machine. Design challenges arising from the high-speed, high-efficiency requirements are presented followed by a discussion of design features that have been introduced to address them. A prototype version of the machine has been fabricated using a segmented stator configuration and segmented neodymium-iron rotor magnets. Test results gathered to date demonstrate promising torque production and efficiency characteristics that are consistent with the machine performance predictions. P.B. Reddy, T.M. Jahns, P.J. McCleer, T.P. Bohn
2010-018 018 Integration of Battery Energy Storage Element in a CERTS Microgrid 2010 IEEE Energy conversion Congress & Expo (ECCE ‘10) Battery, CERTS, Energy Storage, Inverter, Microgrid, SOC, VRLA. Microgrids can employ a variety of sources that work together to supply local power and offer significant system efficiency gains from combined heat and power (CHP). Energy storage elements offer the flexibility to supply power even when intermittent sources are not online, but accurate control of the energy level of the energy storage element is critical to maintaining the bi-directional power capabilities of the energy storage element. A controller is presented and demonstrated here that accomplishes the task of controlling the energy level to within an acceptable range autonomously when commands from a master controller are incorrect or lost. M.J. Erickson, R.H. Lasseter
2010-019 019 Regulation of Permanent Magnet Generators using Angle Control of Stator-Connected Voltage Source Inverters 2010 IEEE Energy conversion Congress & Expo (ECCE ‘10) AC generators, aircraft power systems, interior permanent magnet machines, angle modulation, power generation, power conversion, voltage control. The use of a permanent magnet AC generator (PMACG) with a salient-pole rotor design combined with an appropriate power converter has recently been shown to be an attractive practical approach for implementing small power systems. Although a classical approach to realizing voltage regulation may be developed on the basis of reactive power control in power systems, it presents special challenges for variable-frequency operation, made more difficult by the presence of lightly-damped machine dynamics. This paper presents a simple and effective means for regulating the terminal voltage of the generator by controlling the DC voltage of a stator-connected voltage-source inverter. The paper presents a dynamic model that illustrates the source of lightlydamped behavior, followed by theintroduction of power derivative equivalent feedback into the control system to obtain excellent performance. Computer simulations and experimental results are presented to demonstrate the effectiveness of this control approach. N. Clements, G. Venkataramanan, T.M. Jahns
2010-020 020 Modeling and Analysis of Proximity Losses in High-Speed Surface Permanent Magnet Machines with Concentrated Windings 2010 IEEE Energy conversion Congress & Expo (ECCE ‘10) AC losses, surface PM machines, high speed, permanent magnet, proximity loss, bundle proximity loss, strand proximity loss, conductor loss, eddy current loss, copper loss. Surface permanent magnet (SPM) machines can be designed with fractional slot-concentrated windings (FSCW) to achieve extended speed ranges. High-speed operation can lead to significant levels of proximity losses in the stator windings due to substantial spatial harmonic magnetic fields in the air-gap as well as the high-frequency currents themselves. An integrated analysis tool is presented in this paper to calculate the strand- and bundle-level proximity losses in slotted stator conductors without requiring finite element analysis. A combination of analysis techniques, including Laplace equation solutions and conformal mapping, is used to estimate the magnetic field in each stator slot, providing the basis for proximity loss estimation. The match between losses estimated using the analytical model and finite element analysis is very promising. P.B. Reddy, T.M. Jahns, T.P. Bohn
2010-021 021 Unsaturated and Saturated Saliency Trends in Fractional-Slot Concentrated-Winding Interior Permanent Magnet Machines 2010 IEEE Energy Conversion Congress & Expo (ECCE ‘10’) Electric machines, interior permanent magnet machines, fractional slot concentrated winding, saturated saliency, unsaturated saliency. This paper presents an investigation of trends in the unsaturated and saturated magnetic saliency values of interior permanent magnet (IPM) synchronous machines with fractional-slot concentrated windings (FSCW). This paper investigates alternative slot-pole combinations for FSCW-IPM machines, highlighting the key observation that the saliency of these machines is generally lower than their counterpart IPM machines with conventional distributed windings. The relative merits and challenges of FSCW-IPM machines are examined, with a focus on the contribution of reluctance torque to the total machine torque. A key design metric that proves useful in this discussion is “unsaturated saliency ratio”, defined as the ratio Lq/Ld in the limiting case of near zero stator current and “saturated saliency ratio”, defined as the ratio Lq/Ld at high stator current. An important objective is to use this parameter to help machine designers choose the most appropriate slot-pole configuration for an FSCW-IPM machine in order to achieve the desired performance requirements. J.K. Tangudu, T.M. Jahns, A. El-Refaie
2010-022 022 Surface Permanent Magnet Synchronous Machine Design for Saliency-Tracking Self-Sensing Position Estimation at Zero and Low Speeds Proc. of IEEE IAS Pulp and Paper Industry Conf., June 21-23, 2010, San Antonio TX. IEEE Trans. on Ind. Appl., Vol. 47, No. 4, Jul/Aug 2011 pp. 1612-1623 SPM machine, machine design, self-sensing, high frequency injection, saliency tracking Elimination of externally mounted position sensors and their associated cables is a goal for virtually all drive manufacturers. This paper addresses design methods of surface permanent magnet (SPM) synchronous machines for saliency-tracking self-sensing (position sensorless) position estimation. Machine saliency is created by stator magnetic saturation due to the rotor zigzag leakage flux from surface permanent magnets. Using the machine saliency created by zigzag leakage flux can allow a SPM machine to be suitable for saliency-tracking position estimation without the need of any further special rotor design modification. In addition, another major benefit is achieved, i.e. a saliency role reversal whereby Ld>Lq. This has the advantage of reducing machine crosssaturation and increasing the feasible region for accurate position estimation. All the design procedures are verified by the finite element analysis (FEA), and a 50W SPM machine prototype is used for performance validation. S.C. Yang, R.D. Lorenz, T.M. Jahns, T. Suzuki
2010-023 023 Deadbeat-Direct Torque & Flux Control Motor Drive Using a Single Control Law to Minimize Motor Losses Proc. of Int'l Conf on Electrical Machines and Systems, ICEMS, Oct. 10-13 2010, Incheon, South Korea. Deadbeat, direct torque control, flux control, high performance induction machine drive, loss minimizing control, efficiency optimization. This paper presents an implementation of deadbeatdirect torque and flux control (DB-DTFC) for AC induction machine drives that demonstrates nearly ideal properties over a wide range of flux and torque operating conditions and its application to motor loss minimization. A key attribute of DBDTFC is that the control law is the sameover the entire operating space, including steady-state and transient operation at the voltage limits. This DB-DTFC implementation allows for an additional degree of freedom to select a broad range of stator flux linkages at light to medium loads. This paper presents animplementation of DB-DTFC and experimentally demonstrates its performance over a full range of operating conditions and its application to minimizing machine losses. T. Obermann, Z. Hurst, B. Bradley, R.D. Lorenz
2010-024 024 State Space Decoupling Control Design Methodology for Switching Converters Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2010), Sept. 12-16, 2010, Atlanta, GA, Eletronica de Potencia (Brazilian Journal of Power Electronics), Vol. 17, No. 1, Dec 2011/Feb 2012, pp. 456-465 DC-DC converter, State space control, Voltage regulators, disturbance input decoupling. This paper derives a new approach for analyzing dc-dc converters for feedback control design. The control-tooutput voltage transfer function of the converters, usually predicted by averaging models, and the classical feedback control techniques are replaced by the state space average state block diagram analysis. These state block diagrams are obtained for state space averaging matrixes of the converters combined with their continuous conduction mode differential equations. This decoupling technique yields first order control transfer functions allowing easier synthesis of controllers. Thedisturbance rejection properties of the controller are analyzed and improved by disturbance input decoupling. The technique is applied to buck converters, and the controllers demonstrate good transient response compared to classical voltage controllers. The structure is easy implement with relevant applications in integrated circuit manufacturing and general industrial environments. E.C. Gomes, L.A.R. Souza, S. Catunda, R.D. Lorenz, J.V. Caracas
2010-025 025 An Examination of AC/HVDC Power Circuits for Interconnecting Bulk Wind Generation with the Electric Grid Energies 2010, 3, 1263-1289. bulk transmission; HVDC; multi-terminal; offshore; wind farm; VSC; CSC; modular multilevel converter The application of high voltage dc (HVDC) transmission for integrating large scale and/or off-shore wind generation systems with the electric grid is attractive in comparison to extra high voltage (EHV) ac transmission due to a variety of reasons. While the technology of classical current sourced converters (CSC) using thyristors is well established for realization of large HVDC systems, the technology of voltage sourced converters (VSC) is emerging to be an alternative approach, particularly suitable for multi-terminal interconnections. More recently, a more modular scheme that may be termed ‘bridge of bridge’ converters (BoBC) has been introduced to realize HVDC systems. While all these three approaches are functionally capable of realizing HVDC systems, the converter power circuit design trade-offs between these alternatives are not readily apparent. This paper presents an examination of these topologies from the point of view of power semiconductor requirements, reactive component requirements, operating losses, fault tolerance, multi-terminal operation, modularity, complexity, etc. Detailed analytical models will be used along with a benchmark application to develop a comparative evaluation of the alternatives that maybe used by wind energy/bulk transmission developers for performing engineering trade-off studies. D. Ludois, G. Venkataramanan
2010-026 026 Development and Validation of Models for 95% Efficiency, 220 W Wireless Power Transfer over a 30 cm Air-gap Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2010), Sept. 12-16, 2010, Atlanta, GA. IEEE Trans. on Ind. Appl., Vol. 47, No. 6, Nov/Dec 2011 pp. 2495-2504. equivalent circuit, large air-gap, proximity effect, skin effect, spatial layout, wireless power transfer. Although 60W wireless power transfer was demonstrated in 2007, still there is no equivalent circuit model for a sub-meter air-gap, hundreds of Watts, high efficiency wireless system. A design-oriented circuit model is needed for this technology to evolve. This paper proposes an equivalent circuit model for the wireless system and analyzes the system based on the proposed model. The proposed model and its analysis are validated by means of FEA and experimental results. Furthermore, as a viable solution for high power (over 10kW) applications, losses in the wireless power transfer system are investigated in the following section. Because of the high operating frequency (MHz), skin- and proximity effect were shown to be dominant. New spatial layout of a coil is proposed that significantly reduces losses caused by skin- and proximity effect. Proposed coil design is evaluated by means of FEA. S-H. Lee, R.D. Lorenz
2010-027 027 Integrating Giant Magneto-Resistive (GMR) Field Detectors for High Bandwidth Current Sensing in Power Electronic Modules Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2010), September 12-16, 2010, Atlanta, GA. IEEE Trans on Ind. Appl., Vol. 48, No. 4, Jul/Aug 2012 pp. 1432-1439. Integrated current measurement, giant magneto-resistance (GMR). This paper analyzes the placement of giant magneto-resistive (GMR) field detectors in power electronic modules. GMR field detectors can provide simultaneous high bandwidth (DC to MHz) current and temperature measurements in a small area (1.26 mm2 ). The GMR detects incident magnetic fields, and because the spatial magnetic field from current carrying conductors is dependent on frequency, a precise 5% Flat Bandwidth (FBW) metric is used to evaluate placement of the GMR detectors. One significant contribution of this paper is to identify the effects of conducting material near a current carrying conductor on the FBW performance, and to propose a methodology to achieve high FBW performance inside a power electronics module where conducting material is near the current carrying conductor. This paper also introduces a method using multiple GMR detectors to reduce the placement tolerances of the GMR detectors. P.E. Schneider, R.D. Lorenz, M. Horio
2010-028 028 Using the Motor Drive as a Sensor to Extract Spatially Dependent Information during Servo Operation Using the Motor Drive as a Sensor to Extract Spatially Dependent Information during Servo Operation," Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2010), Sept. 12-16, 2010, Atlanta, GA. IEEE Trans. on Ind. Appl., Vol. 47, No. 3, May/Jun 2011 pp. 1344-1351. AC Drives, Sampling Methods, State Estimation, Signal Representations, Order Tracking, Spatial Sampling, Fault Diagnosis This paper presents a methodology for extracting useful spatial signals using the motor drive as the sensor during servo operation. Spatially dependent phenomena yield nonstationary frequency content during servo operation. With variable frequency and frequency dependent amplitude in the current and torque signals, the underlying, valuable spatial information is difficult to extract using conventional frequency domain approaches. The methodology presented uses the motor drive to estimate the spatially dependent disturbance torque information during servo operation using spatial domain resampling of temporal domain signals internal to the motor drive. Spatial domain information is speed invariant, making it accessible even during servo operation. Additionally, this paper develops a framework to operate through varying speeds to help isolate the systematic, spatially dependent content using spatial synchronous averaging. These methods and concepts are evaluated through simulation as well as experimentation. This methodology can be utilized to provide robust control of machines through identification of spatial components, as well as improve diagnostics of machine and load degradation. C.M. Wolf, R.D. Lorenz
2010-029 029 Deadbeat-Direct Torque and Flux Control Motor Drive Over a Wide Speed, Torque and Flux Operating Space Using a Single Control Law Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2010), Sept. 12-16, 2010, Atlanta, GA. Deadbeat, direct torque control, flux control, voltage limited operation, high performance induction machine drive. This paper presents an implementation of deadbeatdirect torque and flux control (DB-DTFC) for AC induction machine drives that demonstrates nearly ideal properties over a wide range of flux and torque operating conditions, including deep field weakening. A key attribute of this DB-DTFC is that the control law is the same over the entire operating space, including steady-state and transient operation at the voltage limits. By comparison, field oriented control at the voltage limit is inherently compromised and requires adjustment of the current control laws. Similarly, PI control-based DTFC becomes oscillatory under voltage limit conditions. This DBDTFC implementation requires no change tothe control law under voltage limit conditions. This paper presents an implementation of DB-DTFC and experimentally demonstrates its performance over a full range of operating conditions, including operation at the voltage limit. T.R. Obermann, Z.D. Hurst, R.D. Lorenz
2010-030 030 Novel Design of Flux-Intensifying Interior Permanent Magnet Synchronous MachineSuitable for Power Conversion and Self-Sensing Control at Very Low Speed Proc. of IEEE Energy Conversion Congress and Exposition (ECCE2010), Sept. 12-16, 2010, Atlanta, GA. carrier signal injection, finite-element analysis (FEA), flux barriers, flux intensifying, flux weakening, interior permanent magnet synchronous machines, saliencytracking, saturation effects, self-sensing This paper proposes a new rotor design for flux intensifying, interior permanent magnet synchronous machine (FI-IPM SM) which has similar torque-speed and power capabilities to a traditional flux weakening, IPM SM (FW-IPM SM). Design steps for the rotor structure of the new machine are laid out and discussed to emphasize key design challenges. The proposed FI-IPM SM and a conventional FW-IPM SM with similar torque-speed capability, are used to evaluate performance in power conversion as well as self-sensing capability at very low speed. Finite-element analysis (FEA) is used to evaluate each machine's performance. The proposed FIIPM SM shows less variation in thesaliency when the machine is loaded, leading to a possibility of better self-sensing performance at very low speed as compared to the traditional FW-IPM SM. Experimental results on the efficiency and selfsensing performance of these two machines are presented to verify the design methodology. N. Limsuwan, Y. Shibukawa, D. Reigosa, and R.D. Lorenz
2010-031 031 Inductor Design Methods with Low-permeability RF Core Materials IEEE Energy Conversion Congress and Exposition, pp. 4376-4383, Sept. 2010 This paper presents a design procedure for inductors based on low-permeability magnetic materials for use in very high frequency (VHF) power conversion. The proposed procedure offers an easy and fast way to compare different magnetic materials based on Steinmetz parameters and quickly select the best among them, estimate the achievable inductor quality factor and size, and ?nally design the inductor. Geometry optimization of magnetic-core inductors is also investigated. The proposed design procedure and methods are verified by experiments. Y. Han & D.J. Perreault
2010-032 032 Scalable, Low-Cost, High Performance IPM Motor for Hybrid Vehicles IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 47, NO. 6, NOVEMBER/DECEMBER 2011,pp.2495-2504. Hybrid, Interior, Motor, Permanent Magnet, Scalable, Rotor, Windings Electric drive systems, which include electric machines and power electronics, are a key enabling technology for advanced vehicle propulsion systems that reduce the petroleum dependence of the ground transportation sector. To have significant effect, electric drive technologies must be economical in terms of cost, weight, and size while meeting performance and reliability expectations. This paper will provide an overview of the DoE/GE project to develop scalable, low-cost, highperformance next generation IPM traction motors for hybrid applications. The goal is to leap frog the state of the art and meet the FredomCar 2020 specifications. The paper will include the analytical and test results of the first proofof-principle machine, analytical and preliminary test results for the second proof-of-principle machine as well as next steps. A.M. EL-Refaie, J.P. Alexander, S. Galioto, M.R. Shah, K. Huh, W.D. Gerstler, J. Tangudu, T.M. Jahns
2010-033 033 Plug-in Electric Vehicle Interactions with a Small Office Building: An Economic Analysis using DER-CAM Invited Panel Paper presented at the 2010 IEEE Power Engineering Society. Meeting, July 2010, Minneapolis, MN. battery storage, building management systems, dispersed storage and generation, electric vehicles, load management, microgrid, optimization methods, power system economics, road vehicle electric propulsion It is generally believed that plug-in electric vehicles (PEVs) offer environmental and energy security advantages compared to conventional vehicles. Policies are stimulating electric transportation deployment, and PEV adoption may grow significantly. New technology and business models are being developed to organize the PEV and building interface and their interaction with the wider grid. This paper analyzes the PEVs’ integration into a building’s Energy Management System (EMS). This relationship is modeled by the Distributed Energy Resources Customer Adoption Model (DER-CAM), which finds optimal equipment combinations to meet microgrid requirements at minimum cost, carbon footprint, or other criteria. Results show that vehicle batteries are valuable to the building and a contractual relationship that shares the benefit between building and vehicle owner is possible. Under a simple annual fixed payment and energy exchange agreement, vehicles are primarily used to avoid peak demand charges and supply cheaper off-peak electricity to the building during workdays. I. Momber, T. Gomez, G. Venkataramanan, M. Stadker, S.Beer, J. Lai, C. Marnay, V. Battaglia
2010-034 034 On the Choice of Voltage Regulators for Droop-controlled Voltage Source Converters in Microgrids to Ensure Stability Proceedings of the IEEE ECCE 2010, Atlanta, GA. microgrids, voltage source converters, stability, droop. Microgrids are emerging to be an attractive means to cluster various distributed generation systems with local loads while operating either in a grid-connected mode or in an islanded mode in a semi-autonomous fashion. Voltage source converter (VSC) based distributed generation devices are often an essential component in such microgrids, particularly in interfacing dc energy storage devices. While system level control of VSCs that incorporate frequency and voltage droop have been shown to be essential in ensuring autonomous system operation in a distributed manner, the impact of VSC internal voltage regulator dynamics on system stability has not been de?nitively established. This paper presents a systematic comparison of voltage regulators using a dynamic phasor based model of an inverter system interfaced to an in?nite grid; the model is used to examine system stability boundaries. The impact of various options for realizing VSC voltage regulators in conjuction with varying interconnection system impedance parameters are studied to establish stability boundaries for each case. A dynamic phasor model is used to evaluate operating point stability and the results are verified using computer simulation results. S. Bala, G. Venkataramanan
2010-035 035 Self-Synchronous Control of Doubly-Fed Linear Generators for Ocean Wave Energy Applications Proceedings of the IEEE ECCE 2010, Atlanta, GA, pp.2386-2391. ocean wave energy conversion; doubly-fed linear machine control; alternative energy conversion A versatile doubly-fed linear generator was recently presented for application in the point absorber ocean wave energy converter (WEC). Although the machine may be operated as a classical synchronous machine, or as a singly- or doubly-fed induction machine, a self-synchronous approach to operating the machine is found to be attractive in low speed, high force applications. This is particularly beneficial for WECs since operating conditions alternate between positive and negative velocity at low speeds with high force. This characteristic lends itself to the proposed unique control approach. This paper develops the analytical concepts behind this controller as well as detailed simulation results. J. Vining, T.A. Lipo, G. Venkataramanan
2010-036 036 Comparison of IGBT Cycling Capabilities for Different AC/AC Topologies IEEE Transactions on Industry Applications, Vol. 46, 2010, pp.2475-2483. Mean time to failure, power cycle, zero-current switching, zero-voltage switching. This paper analyzes the insulated gate bipolar transistor (IGBT) power cycling capability for a dual-bridge matrix converter (DBMC) used as a motor drive and compares the result with the traditional dc/ac inverter and the conventional matrix converter (CMC). Two pulsewidth modulation (PWM) control methods for the DBMC are investigated. One is called zero-current PWM (ZCPWM), which allows zero current commutation of the rectifier side switches. The other is named zero-voltage PWM (ZVPWM), which generates zero-voltage switching in the inverter IGBT. It is found that the DBMC under the ZVPWM method shows much higher power cycling capabilities in the IGBT than that of the ZCPWM and the other two topologies. Moreover, by appropriately selecting the sequence of the ZVPWM and ZCPWM methods, the DBMC shows overall advantages on the sizing of the IGBT and the balancing of the thermal system. It is also shown that the IGBT applied in the DBMC inverter is easier to operate under higher switching frequency conditions. L. Wei, T.A. Lipo, R.A. Lukaszewski
2010-037 037 Application of a Dual-Half-Controlled- Converter in a PMSG Wind Turbine International Symposium on Power Electronics Electrical Drives Automation and Motion(SPEEDAM), 2010, pp.673-677. DHCC, PMSG, coordinated hysteresis current regulator, complementary configuration, harmonics The configuration and control of a dual-halfcontrolled-converter (DHCC) designed for a permanent magnet synchronous generator (PMSG) wind turbine are proposed in this paper. The system performance is analyzed using Saber simulations. The simulations results demonstrate that by using coordinated current regulation techniques, pure sinusoidal input current waveforms can be achieved and shared equally between the two halfcontrolled-converters (HCC). For the same amount of power throughput and the same number of switches, the current rating required for the switches is significantly lower compared to a voltage source converter (VSC), which brings down the semiconductor cost without sacrificing system performance. Y. Wang, D. Panda, T. A. Lipo
2010-038 038 Half-Controlled-Converter-Fed Open-Winding Permanent Magnet Synchronous Generator for Wind Applications 14th International, Power Electronics and Motion Control Conference(EPE/PEMC), 2010, pp.T4-123-T4-126. Half-controlled-converter, open-winding PMSG, fault tolerance, speed control, current regulation The configuration and control of two cascaded half-controlled-converters (HCC) designed for use with an open-winding permanent magnet synchronous generator (PMSG) wind turbine are investigated in this paper. The system is modeled and simulated in Simulink with the assistance of PLECS. The simulations results demonstrate that by using speed-control-based hysteresis current regulator, pure sinusoidal phase current waveforms can be achieved in the machine windings at various power factors. Compared to an open-winding PMSG fed by two cascaded voltage source converters, the proposed system requires fewer switches but provides identical excellent performance and good fault tolerance. The proposed system is also free of shoot-through issues. Although HCC allows only unidirectional power flow, this is typically not an issue in the wind power applications. Y. Wang, T.A. Lipo, D. Pan
2010-039 039 Design of Grid-Connected to Rotor Type Doubly-Fed Induction Generators for Wind Turbine System 14th Biennial IEEE Conference on Electromagnetic Field Computation(CEFC), 9-12 May 2010. Doubly-Fed Induction Generators (DFIGs) are widely used for modern wind turbines. Although the stator winding of DFIG is directly connected to a grid while a rotor winding is connected to converters, it has a large outer size because of the high current in the stator winding. This paper proposes a grid-connected to a rotor type DFIG where rotor winding is connected to the grid instead of stator winding. In order to verify the size reduction of the proposed type, a loading distribution method (LDM) is utilized. Then the characteristic analysis is performed using the equivalent circuit method (ECM). As a result, the total volume of the proposed type was decreased by about 10.73 %. In addition, the total core weight of the proposed type was also decreased from 24.5 kg to 21.9 kg. S. Kim, Y. You, T.A. Lipo, B. Kwon
2010-040 040 New Control Method Including State Observer of Voltage Unbalance for Grid Voltage-Source Converters IEEE Trans. on Industrial Electronics, Vol.57, June 2010, pp.2054-2056. Disturbance observer, grid voltage-source converters (VSCs), power quality, voltage unbalance. New observer-based disturbance-estimation and control algorithms are introduced in this paper that compensate source voltage unbalances. The algorithms are also designed to compensate the detrimental impact of delay effects caused by the digital-signal processing. Consequently, these techniques are appropriate for higher power systems with reduced pulsewidth modulation switching frequency and limited current-controller bandwidth. Analytical, simulation, and experimental results are presented to illustrate the effectiveness of the new observer-based control techniques. K. Lee, T.M. Jahns, T.A. Lipo, V. Blasko
2011-001 001 Surface Permanent Magnet Machine Self-Sensing At Zero and Low Speeds Using Improved Observer for Position, Velocity, and Disturbance Torque Estimation Proc. of Int'l Electric Machines and Drives Conf (IEMDC), May 15-18, 2011, Niagara Falls, NY. IEEE Trans. on Ind. Appl., Vol. 48, No. 1, Jan/Feb 2012 pp. 151-160 High-frequency injection, observer design, selfsensing, sensorless control, surface permanent-magnet (SPM) machine. This paper proposes an improved method for the estimation of position, velocity, and disturbance torque in a surface permanent-magnet (SPM) machine self-sensing (position sensorless) drive that uses high-frequency (HF) voltage injection. SPM machines traditionally do not have enough position-dependent signals because their symmetric rotors result in near-zero spatial saliency. A separate disturbance observer and a saliency-tracking observer with speed-varying bandwidth (BW) tuning are used together to improve the disturbance rejection performance while maintaining the accuracy of self-sensing position and velocity estimation. According to the experimental evaluation, the proposed estimation method can achieve higher BW for the disturbance estimation and decoupling which can increase the stiffness of SPM machine closed-loop self-sensing control. This paper includes experimental comparative evaluation of closed-loop encoder-based versus closed-loop self-sensing-based operation of a SPM machine drive. S.C. Yang, R.D. Lorenz
2011-002 002 Estimation of Sheet Modulus of Elasticity Using Drive Field Signals Proc. of IEEE IAS Pulp & Paper Industry Conf., June 20-23, 2011, Nashville, TN. IEEE Trans. on Ind. Appl., Vol. 48, No. 5, Sept/Oct 2012 pp. 1758-1772. Control of modulus of elasticity, elastic strip control, modulus of elasticity, multispan systems, sensorless tension control. Online sensing of sheet modulus of elasticity in the dry-end spans of printing grade paper machines (PMs) will permit the machine operators to control the mechanical properties of the produced paper. This paper develops an integrated sensorless tension control and sheet modulus of elasticity estimation algorithm, which is tested using field-recorded signals from a production PM and using a full model of the dry-end sections of this machine. Results show the ability of the proposed estimation algorithm to predict the sheet tension (tensile force) and sheet modulus of elasticity even in the presence of rapid changes in the speed and/or in other process operating conditions. The developed algorithms offer the papermaker new insights into the papermaking process. The ability to understand how modulus changes in real time provides a pathway to optimizing the operation of the PM drive system. M.A. Valenzuela, J.M. Bentley, R.D. Lorenz
2011-003 003 Comparison of PV Inverter Controller Configurations for CERTS Microgrid Applications 2011 IEEE Energy Conversion Congress and Exposition (ECCE'11) September 18-22, 2011 Phoenix, AZ. Photovoltaic, PV, CERTS, energy storage, inverter, microgrid, grid forming, grid following. Microgrids are highly compatible with photovoltaic (PV) sources because of their ability to internally aggregate and balance multiple PV sources without imposing restrictions on the penetration of such intermittent power sources. There are two major types of inverter control configurations that are used in photovoltaic inverters to provide an interface to a CERTS microgrid. These control configurations exhibit important duality characteristics, and both are capable of tracking maximum input power while abiding by the CERTS droop algorithms. This paper investigates and demonstrates the comparative performance characteristics of these two major controller types: 1) a gridforming droop-style controller similar tothose used for controlling distributed generators; and 2) a current-regulated grid-follower controller. It is shown that only the grid-forming controller allows a PV source to operate alone in an islanded CERTS microgrid, but the grid-follower controller enjoys some inherent advantages with regard to faster dynamic response. M. Erickson, T.M. Jahns, R.H. Lasseter
2011-004 004 Design, Analysis and Loss Minimization of a Fractional-Slot Concentrated Winding IPM Machine for Traction Applications 2011 IEEE Energy Conversion Congress and Exposition (ECCE'11) September 18-22, 2011 Phoenix, AZ. Electric machines, fractional-slot concentrated windings, interior permanent magnet synchronous machines, electric traction motor. This paper presents details of the design and analysis of a high-performance fractional-slot concentrated winding (FSCW) interior permanent magnet (IPM) machine that has been designed to meet demanding FreedomCAR traction machine specifications. Attention is focused on the design of the IPM rotor, including investigations of the impact of varying the magnet height and the depth of the magnet chevron midpoint on key performance metrics. This paper also addresses interaction between the electromagnetic and structural characteristics of the rotor as bridge and post widths are varied. Predicted performance characteristics of the machine are presented and design techniques are described for improving the machine efficiency at high operating speeds. Test results gathered from an experimental machine exhibit promising agreement with the predicted performance. J.K. Tangudu, T.M. Jahns, T.P. Bohn
2011-005 005 Improved Nonlinear Model for Electrode Voltage-Current Relationship for More Consistent Online Battery System Identification 2011 IEEE Energy Conversion Congress and Exposition (ECCE'11) September 18-22, 2011 Phoenix, AZ. state-of-charge (SOC), state-of-function (SOF), electric vehicle (EV), battery management system (BMS), leadacid battery, Butler-Volmer equation, Kalman filter. An improved nonlinear model for the electrode voltage-current relationship for online battery system identification is proposed. In contrast with the traditional linear-circuit model, the new approach employs a more accurate model of the battery electrode nonlinear steady-state voltage drop based on the Butler-Volmer equation. The new form uses an inverse hyperbolic sine approximation for the Butler-Volmer equation. Kalman filter-based system identification is proposed for determining the model parameters based on the measured voltage and current. Both models have been implemented for lead-acid batteries and exercised using test data from a Corbin Sparrow electric vehicle. A comparison of predictions for the two models demonstrates the improvements that can be achieved using the new nonlinear model. The results include improved battery voltage predictions that provide the basis for more accurate state-of-function (SOF) readings. L.W. Juang, P.J. Kollmeyer, T.M. Jahns, R.D. Lorenz
2011-006 006 Comparison of Interior PM Machines with Concentrated and Distributed Stator Windings for Traction Applications 2011 IEEE Vehicle Power and Propulsion Conference (VPPC'11) September 6-9, 2011 Chicago, IL . Electric machines, fractional-slot concentrated winding, integral-slot distributed winding, interior permanent magnet machines, FreedomCAR, traction motor. This paper presents a detailed design comparison of two types of high-performance interior permanent magnet (IPM) synchronous machines designed to meet demanding FreedomCAR traction machine specifications, one with fractional-slot concentrated windings (FSCW) and the other with integral-slot distributed windings (ISDW). An IPM rotor that was originally designed for an FSCW stator with a slotsper-pole-per-phase (SPP) value of 2/5 and double-layer windings is used in all four of the studied designs. This comparative investigation is carried out using finite element analysis with both single- and double-layer winding configurations. Key performance metrics are compared including the predicted back-EMF, the characteristic current, cogging torque, and highspeed losses under full load operating conditions. J.K. Tangudu, T.M. Jahns
2011-007 007 Evaluation of an Electromechanical Model for a Corbin Sparrow Electric Vehicle 2011 IEEE Vehicle Power and Propulsion Conference (VPPC'11) September 6-9, 2011 Chicago, IL. An electromechanical model of a Corbin Sparrow, a small electric vehicle, is evaluated using a collection of experimental drive data. The vehicle's stock electromechanical drive train and a custom-designed data logging system are presented, and the model equations and parameters are summarized. The experimental results demonstrate that the model can deliver promising accuracy when estimating the vehicle power versus time as a function of the vehicle's velocity, acceleration, and vertical velocity. A single drive trip and a collection of drive trips are analyzed, and the model is shown to have a typical error range of approx. -5%/+20%. Statistics for the collected drive data are also provided, including the vehicle's measured energy consumption per mile, motor efficiency, and motor controller efficiency. Finally, the Sparrow's energy consumption is compared to that of electric vehicles tested by the US Department of Energy, and the Sparrow performance is predicted with installation of regenerative braking, a more efficient motor and controller, and a lithium-ion battery pack. P.J. Kollmeyer, L.W. Juang, T.M. Jahns
2011-008 008 Development of an Electromechanical Model for a Corbin Sparrow Electric Vehicle 2011 IEEE Vehicle Power and Propulsion Conference (VPPC'11) September 6-9, 2011 Chicago, IL. A method for modeling a Corbin Sparrow, a small electric vehicle (EV), is presented in this paper. The model is divided into two parts: (1) the mechanical dynamics model - the physics-based model that estimates how much power is necessary to accelerate the vehicle's mass and overcome various sources of friction; and (2) the electromechanical drive train model - the model of the motor and power electronics drive that estimates how much power must be drawn from the battery to develop the mechanical power at the motor shaft. This model improves on prior EV modeling by: 1) demonstrating how parameters can be measured from real-world driving data; 2) incorporating elevation data estimated with GPS and an electronic topographic map; and 3) using the model to estimate the vehicle energy consumption as a function of speed and rate of acceleration. More information about the performance of this model using actual drive data is presented in a separate paper. P.J. Kollmeyer, L.W. Juang, T.M. Jahns
2011-009 009 Inductor Design Methods with Low-permeability RF Core Materials IEEE Energy Conversion Congress and Exposition, pp. 4376-4383, Sept. 2010. This paper presents a design procedure for inductors based on low-permeability magnetic materials for use in very high frequency (VHF) power conversion. The proposed procedure offers an easy and fast way to compare different magnetic materials based on Steinmetz parameters and quickly select the best among them, estimate the achievable inductor quality factor and size, and finally design the inductor. Geometry optimization of magnetic-core inductors is also investigated. The proposed design procedure and methods are verified by experiments. Y. Han, D.J. Perreault
2011-010 010 A New Architecture for Battery Charge Equalization IEEE Energy Conversion Congress and Exposition, Sept. 2011, accepted.. One limitation of many battery charge equalizers is their slow equalization speed, especially when there are a largenumber of batteries in the series-string in high voltage and high power applications. This paper presents a newarchitecture for battery charge equalization. In this architecture, independent equalizers are placed in different layers and all the layers can equalize corresponding batteries simultaneously, thus reducing equalization time by 50%. We explore the operation, performance characteristics, and design of the architecture. Both simulation and experimental results are presented to validate the analysis in the paper. B. Dong, Y. Han
2011-011 011 Scalability Investigation of Proximity Losses in Fractional-Slot Concentrated Winding Surface PM Machines during High-Speed Operation 2011 IEEE Energy Conversion Congress and Exposition (ECCE'11) September 18-22, 2011 Phoenix, AZ. AC losses, surface PM synchronous machines, high speed, permanent magnet, fractional-slot concentrated windings, proximity losses, eddy current losses, copper losses. In previous work, an integrated analysis tool for predicting the strand- and bundle-level proximity losses was developed and experimentally verified using a 30 kW(continuous) surface permanent magnet (SPM) machinedesigned with fractional-slot concentrated windings. In this extended work, a new 200 kW (continuous) FSCW-SPM machine has been designed based on commercial specifications for a high-performance electric traction machine. Predicted proximity losses developed by applying the integrated analysis tool to this 200 kW machine match finite element analysis predictions very well over the speed range from 1500 r/min (corner point) to 6000 r/min (maximum speed). In addition to confirming the scalability of the proximity loss analysis tool to higher power machines, this investigation has also demonstrated that these larger FSCW-SPM machines are vulnerable to high proximity losses at high speeds. Special design features such as transposing the stator winding strands must be taken to suppress these losses that can otherwise reach unacceptably high levels without these techniques. P.B. Reddy, T.M. Jahns
2011-012 012 Comparison of Interior and Surface PM Machines Equipped with Fractional-Slot Concentrated Windings for Hybrid Traction Applications 2011 IEEE Energy Conversion Congress and Exposition (ECCE'11) September 18-22, 2011 Phoenix, AZ. Comparison, concentrated, fractional-slot, high speed, interior, machines, permanent magnet, surface, traction, windings. Electric drive systems, which include electric machines and power electronics, are a key enabling technology for advanced vehicle propulsion systems that reduce the petroleum dependence of the ground transportation sector. To have significant effect, electric drive technologies must be economical in terms of cost, weight, and size while meeting performance and reliability expectations. This paper will provide details of the design, analysis and testing of two permanent magnet (PM) machines that were developed to meet the FreedomCar 2020 specifications. The first machine is an Interior PM (IPM) machine and the second machine is a surface PM (SPM) machine. Both machines are equipped with fractional-slot concentrated windings (FSCW). The goal of the paper is to provide a quantitative assessment of how achievable this set of specifications is as well as a comparison with the state of the art. The paper will also quantitatively highlight the tradeoffs between IPM and SPM FSCW machines especially in the context of traction applications. P.B. Reddy, A. El-Refaie, K. Huh, J.K. Tangudu, T.M. Jahns
2011-013 013 Comparison of Resistance-Based and Inductance-Based Self-Sensing Control for Surface Permanent Magnet Machine Using High Frequency Signal Injection Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2011), Sep. 19-21, 2011, Phoenix, Arizona, IEEE Trans. On Ind. Appl., Vol. 48, No. 3, May/June 2012 pp. 977-986 SPM machine, sensorless control, self-sensing, high frequency injection, eddy current This paper presents injection-based self-sensing (position sensorless) control methods for surface permanent magnet (SPM) machines with highly symmetric rotors. Two suitable position-dependent spatial saliency signals are compared. The two signals relate to inductance variation due to stator tooth saturation and resistance variation due to high frequency (HF) eddy current losses. Finite element analysis (FEA) is performed to investigate the properties of two saliency signals in different SPM machines. Implementation methods as well as advantages for closed-loop self-sensing control are discussed. This paper includes experimental comparative evaluation of resistance-based versus inductance-based closedloop self-sensing control performance in a SPM machine using concentrated windings. S.C. Yang, R.D. Lorenz
2011-014 014 Deadbeat-Direct Torque and Flux Control for Interior PM Synchronous Motors Operating at Voltage and Current Limits Proc. of Int'l Conference on Electrical Machines and Systems (ICEMS), Aug. 20-23, 2011, Beijing, China. Wide-speed deadbeat-direct torque and flux control (DB-DTFC), inverter voltage and current constraints, interior permanent-magnet synchronous motors (IPMSMs), Available inverter voltage maximization. This paper proposes a wide-speed deadbeat-direct torque and flux control (DB-DTFC) method associated with inverter voltage and current constraints of interior permanentmagnet synchronous motors (IPMSMs).The proposed approach has potential advantages controlling torque and flux linkage at voltage and current limits since integrators are not involved for torque control or flux weakening. An automatic transition between non-limited operation and six-step modulation can be achieved without modifying the control law. To support this, we provide a graphical and analytic analysis that naturally leads to a unique stator voltage vector selection on the hexagon. The proposed controller can maximize the available inverter voltage and generate higher output torque than conventional current vector controllers at high speeds. The method developed in this paper also maintains beneficial DTC features, such as fast dynamics and direct manipulation of the stator flux linkage for flux weakening. C.H. Choi, J.K. Seok, R.D. Lorenz
2011-015 015 Position Self-Sensing Evaluation of a FI-IPMSM based on High Frequency Signal Injection Methods Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2011), Sep. 19-21, 2011, Phoenix, Arizona, IEEE Tans. On Ind. Appl., Vol. 49, No. 2, March/April 2013 pp. 880-888 Carrier signal injection, flux-intensi?ed interior permanent-magnet synchronous machine (IPMSM) (FI-IPMSM), interior permanent-magnet machines, self-sensing, sensorless. The flux-intensified interior permanent-magnet synchronous machine (IPMSM) (FI-IPMSM) lends itself to designing for good self-sensing properties. This paper begins by evaluating the self-sensing position estimation performance of a suitably designed FI-IPMSM machine using different high-frequency injection methods. This paper then uses an alternative square-wave injection method to estimate the FI-IPMSM rotor position. The experiment results show that the estimation accuracy and system robustness are improved. It is known that secondary saliencies and saliency offset caused by the saturation of the machine can degrade the estimation accuracy. This paper also includes modeling, measurement, and decoupling methods that mitigate these undesirable effects, which are also implemented using an experimental FI-IPMSM. Estimation accuracy and torque ripple caused by the injection current are examined for this FI-IPMSM. Comparisons of the methods are presented. C.Y. Yu, J. Tamura, D. Reigosa, R.D. Lorenz
2011-016 016 Secondary Resistive Losses with High-frequency Pulsating Injection-based Self-sensing IEEE Trans. on Ind. Appl., Vol. 49, No. 4, Jul/Aug 2013 pp 1499-1507. N. Limsuwan, T. Kato, C.Y. Yu, J. Tamura, R. Reigosa, K. Akatsu, R.D. Lorenz
2011-017 017 Evaluation of Point Field Sensing in IGBT Modules for High Bandwidth Current Measurement Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2011), Sep. 19-21, 2011, Phoenix, Arizona. This paper evaluates field-based current sensing integration in power electronic modules. Point field detectors, such as GMR detectors, can provide high bandwidth (DC to MHz) current measurements with a small footprint (1.26 mm2). Magnetic fields surrounding a current carrying conductor are frequency dependent, so the 5% Flat Bandwidth (FBW) metric is used to evaluate placement of the point field detectors to maximize the bandwidth of the current measurement. A significant contribution of this paper is an evaluation of the placement of point field detectors inside a power switching module. The paper focuses on detector placement for the interconnect structures commonly found in power switching modules. Experimental and finite element analysis of wire bond structures with multiple wire bonds and lead frame structures are evaluated for high bandwidth sensing performance.1 P.E. Schneider, R.D. Lorenz
2011-018 018 Analysis of Eddy Current Losses in Surface Permanent Magnet Machine for Injection-based Self-Sensing Position Estimation Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2011), Sep. 19-21, 2011, Phoenix, Arizona, IEEE Trans. on Ind. Appl., Vol. 48, No. 6, Nov/Dec 2012 pp. 1901-1910 High-frequency (HF) signal injection, iron loss, self-sensing, sensorless control, surface-permanent-magnet (SPM) machine. This paper presents a systematic analysis of iron and magnet losses in surface-permanent-magnet (SPM) machines for the position estimation using high-frequency (HF) signal injection. Standard SPM machines with cylindrical rotors are analyzed. It is shown that the magnet eddy current loss due to the superimposed HF signal should be considered for SPM-machine injection-based position estimation. With a proper machine design, the resulting HF armature flux linkage in the magnet can convert to the HF leakage flux in the stator. The decreased magnet eddy current loss can be achieved, leading to better performance on both power conversion and injection-based position estimation. This paper includes the experimental evaluation of two SPM machines with different winding configurations. S.C. Yang, R.D. Lorenz
2011-019 019 A Design Methodology for Wireless Power Transfer Systems Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2011), Sep. 19-21, 2011, Phoenix, Arizona. In a loosely coupled kW level wireless power transfer system, it is difficult to consider multiple design considerations simultaneously because of the system complexity. Circuit design methodology is critical to achieve efficient, low VA rating, and stable system. In this paper, a design methodology for a loosely coupled series-parallel resonant system is proposed. Proposed design methodology is evaluated by a 3kW, 30cm distance power transfer design example. Using the methodology, efficiency, VA rating, stability, and safety issues are considered simultaneously. The example model is implemented by means of FEA. A surface spiral winding transmitter coil is used in the FEA model. Quality factor (Q) dependence of surface spiral winding on mechanical design parameters is investigated to maximize the Q. Based on the investigation, a high Q coil is designed for the system and the coil is used as a transmitter to evaluate the proposed methodology. S.H. Lee, R.D. Lorenz
2011-020 020 In-Situ Measurement of Wirebond Strain in Electrically Active Power Semiconductors Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2011), Sep. 19-21, 2011, Phoenix, Arizona, IEEE Trans. on Ind. Appl., Vol. 49, No. 2, March/April 2013, pp. 973-981. Electronics packaging, optical interferometry, phase shifting interferometry, semiconductor device reliability, semiconductor device testing. Thermal–mechanical displacement/strain in power semiconductor devices is investigated using electronic speckle pattern interferometry (ESPI). Validated models for thermal–mechanical strain are key to improving the reliability of power electronics modules. ESPI is a noncontact optical technique capable of providing surface displacement measurements with submicrometer resolution. The significant contribution of this paper is an experimental methodology by which wire-bond displacement/strain can be measured in an active device. Simultaneous in-plane and out-of-plane measurements are combined to accurately measure the displacement field across the wire-bond interface, while decoupling thermal–mechanical deformation not related to wire-bond strain (such as base plate thermal expansion). Experimental results verify the electrical-loss-driven thermal–mechanical displacement/strain in an electrically active discrete insulated gate bipolar transistor switching at 5 kHz. S.M. Avery, R.D. Lorenz
2011-021 021 Surface Permanent Magnet Synchronous Machine Self-Sensing Position Estimation at Low Speed Using Eddy Current Reflected Asymmetric Resistance Proc. of European Power Electronics (EPE 2011), Aug. 30- Sep. 1, 2011, Birmingham, United Kingdom, IEEE Trans. on Power Electronics, Vol. 27, No. 5, May 2012 pp. 2595-2604 Motion control and permanent magnet motor, self-sensing machine, sensorless control. This paper proposes an alternative position estimation method of surface permanent magnet (SPM) machines at low speed using high frequency (HF) voltage injection. SPM machines traditionally do not have enough spatial saliency signals because of their symmetric rotors. The proposed solution is to track the HF eddy-current-reflected asymmetric resistance for position estimation. It is shown that the spatial variation of resistance can be enhanced when an HF voltage is superimposed. Finite element analysis is performed to investigate the asymmetric resistance in different SPM machines. By superimposing ad-axis pulsating vector HF voltage, SPM machines can achieve the position estimation performance with reduced degradation at high load conditions. Implementation methods are developed to track the resistancebased saliency signal for speed and position closed-loop control. An SPM machine prototype with a ring magnet rotor is used for the experimental evaluation. S.C. Yang, R.D. Lorenz
2011-022 022 Time Optimal Torque Control and Loss Minimization of AC Machines Using Deadbeat Direct Torque and Flux Control Proc. of Int'l Conference on Electrical Machines and Systems (ICEMS), Aug. 20-23, 2011, Beijing, China.. This paper presents time optimal torque control in overmodulation and switching level loss minimization control of an induction machine (IM) and an interior permanent magnet synchronous machine (IPMSM) via deadbeat, direct torque and flux control (DB-DTFC). Using DB-DTFC, the stator flux linkage can be manipulated each PWM cycle to minimize losses during normal operation. Due to voltage limits during overmodulation it may take a sequence of incremental torque commands over several PWM periods to achieve a desired air-gap torque that is physically infeasible in one step. In that case, the DB control becomes finite settling step (FSS) control in which the steps may be optimized using time optimal strategies. In this paper, a time optimal FSS control using a DB-DTFC solution during overmodulation and a loss minimizing DB-DTFC solution over the full torque-speed operating space are proposed and evaluated for IM and IPMSM drives. J.S. Lee, W. Xu, Z. Hurst, F. Quattrone, C. Rabus, R.D. Lorenz
2011-023 023 Percussive Drilling Application of Tubular Reciprocating Translational Permanent Magnet Synchronous Motor Proc. of Int'l Conf on Electrical Machines and Systems, ICEMS, Aug. 20-23 2011, Beijing, China. Journal International Conference on Electrical Machines and Systems, Vol. 1. no.4. 2012 pp. 23-28 Permanent magnet motor, Tubular reciprocating translational motor, Percussive drilling, Rate of penetration, Hard rock drilling This paper presents a tubular reciprocating translational motion permanent magnet synchronous motor for percussive drilling applications for offshore oil & gas industry. The motor model and rock model are built up by doing force analysis of the motor and analyzing the physical procesof impact. The optimization of input voltage waveforms to maximize the rate of penetration is done by simulations. The simulation results show that the motor can be utilized in percussive drilling applications and achieve a very large impact force. Simulation results for optimization also show that second harmonic input voltage produces a higher rate of penetration than the sine wave and fourth harmonic input voltages. S. Zhang, L. Norum, R. Nilssen, R.D. Lorenz
2011-024 024 Experimental Evaluation of a Doubly-Fed Linear Generator for Ocean Wave Energy Applications IEEE Energy Conversion Conference and Expo, Sept 2011, Phoenix, AZ. ocean wave energy conversion; linear generator; doubly-fed linear machine control; alternative energy conversion A versatile doubly-fed linear generator was recently presented for application in the point absorber ocean wave energy converter (WEC). Whereas this machine may be operated as a singly- or doubly-fed induction machine or via a self-synchronous approach, operation as a synchronous machine is found to be an attractive method for experimental testing. Using this mode of operation, the generator may be run with a DC field in either the translator or stator, thus producing power from the stator or translator respectively. Given the unique hybrid-flux architecture of this linear generator, synchronous testing in this manner provides a way to quantify the difference in electrical and reactive force production between the translator and stator topologies under WEC operating conditions, i.e. low speed with high force. This paper presents the testing procedure and setup along with detailed prototype results. J. Vining, T.A. Lipo, G. Venkataramanan
2011-025 025 Phase Locked Loop Control of Inverters in a Microgrid IEEE Energy Conversion Conference and Expo, Sept 2011, Phoenix, AZ. Microgrids are small-scale electricity supply networks that have local power generation. This paper considers a control strategy for inverter-based microsources within a microgrid. The general control philosophy within a microgrid is that sources must rely only on local information, yet must cooperate with other sources. To accomplish that goal, the proposed controller uses droop characteristics for active-power/frequency and reactive-power/voltage. The proposed control strategy is based on the use of a phase locked loop to measure the microgrid frequency at the inverter terminals, and to facilitate regulation of the inverter phase relative to the microgrid. This control strategy allows microgrids to seamlessly transition between grid-connected and autonomous operation, and vice versa. The controller has been implemented in an actual microgrid that incorporated multiple sources. The paper provides simulation results and documents the performance of the hardware implementation. M. Surprenant, I. Hiskens*, G. Venkataramanan
2011-026 026 Complex Phasor Modeling and Control of Modular Multilevel Inverters IEEE Energy Conversion Conference and Expo, Sept 2011, Phoenix, AZ. Modular multilevel power converters in a ‘bridge of bridge’ configuration have been introduced recently for realizing ac-dc, dc-ac and ac-ac power conversion functions with voltage step-up and step-down capability, bidirectional power flow and transformerless operation. While different modulation and control approaches have been introduced in an ad-hoc manner in the introductory literature, definitive models that may be used to characterize the steady state and dynamic performance are just beginning to be uncovered. It is the objective of this paper to introduce a canonical phasor or complex vector model to represent the ac variables along with the dc variables that are unique to this family of converters. The model is used to develop a suitable control approach using established techniques. The complex vector model is represented in the synchronously rotating dq reference frame, and illustrated using an application of a dc-ac step-up inverter for residential photovoltaic applications. J. Reed, G. Venkataramanan, F. Martínez
2011-027 027 Low-cost Light-weight Quick-Manufacturable Blades for Human-scale Wind Turbines IEEE Global Humanitarian Technology Conference, Oct 2011, Seattle, WA. small wind turbine, rural electrification, blades, CFD, PVC pipe A novel blade design for small wind turbines intended for residential use in rural locations and/or developing nations has been developed. Traditionally, blades for these turbines are carved from weather resistant woods which may be costly and difficult to manufacture. This work seeks to reduce cost and construction time by developing blades from readily available PVC drainage pipe. The blade design underwent airfoil optimization regarding the blade twist along its length and drop, via computational fluid dynamic (CFD) simulations with open source software. Blades were built of PVC using the new CFD design and tested on field operation; the manufacturing process as well as their performance was monitored and recorded in terms of comparison with classical wood-based design. P. A. Melendez-Vega, G. Venkataramanan, D. Ludois, J. Reed
2011-028 028 Reuse of Post-consumer E-waste for Low Cost Micropower Distribution IEEE Global Humanitarian Technology Conference, Oct 2011, Seattle, WA. rural electrification; transformers; developing nations; recycling; post consumer resources; microwave; E-waste A novel medium voltage distribution system to electrify rural areas in developing nations using post consumer resources is presented in this paper. Using transformers repurposed from discarded microwave ovens to form a medium voltage microgrid, power may be distributed over an area of a few square kilometers while interconnecting a wide variety of generation sources and storage at a fraction of the cost of traditional systems. Microwave oven transformers (MOTs) are systematically characterized for optimal performance in these cases and construction guidelines are provided. A candidate distribution system using MOTs was constructed to deliver power from a small wind turbine to a small building at a horticulture field station. Results from this demonstration project are provided. D. Ludois, J. Lee, P. Mendoza, G. Venkataramanan
2011-029 029 A High-Frequency Resonant Inverter Topology With Low-Voltage Stress IEEE Transactions on Power Electronics, vol. 26, no. 10, pp. 2980-2992, Oct. 2011. Class E inverter, class-F power ampli?er, class inverter, harmonic peaking, radio frequency inverter, very high frequency, VHF power converter. This paper presents a new switched-mode resonant inverter, which we term the 2 inverter, that is well suited to operation at very high frequencies and to rapid on/off control. Features of this inverter topology include low semiconductor voltage stress, small passive energy storage requirements, fast dynamic response, and good design ?exibility. The structure and operation of the proposed topology are described, and a design procedure is introduced. Experimental results demonstrating the new topology are also presented. A prototype 2 inverter is described that switches at 30 MHz and provides over 500 W of radio frequency power at a drain ef?ciency above 92%. It is expected that the 2 inverter will ?nd use as a building block in high-performance dc-dc converters among other applications. J. M. Rivas, O. Leitermann, Y.Han, & D. J. Perreault
2011-030 030 Performance Improvement of Dual-Half-Controlled-Converter and Its Applications in Utility Rectifiers IEEE ECCE-Asia, Jeju Island, May 30-June3, 2011. Half-controlled-converter, interleaving, PWM, volt-seconds This paper presents improved control techniques for the three-phase three-wire dual-halfcontroller- converter (DHCC) using an interleaved pulsewidth- modulation (PWM) technique. Compared with the hysteresis controller presented in earlier literatures, the proposed PWM controllers require smaller filtering elements and/or a lower sampling frequency. While the same number of active switches are used compared to a conventional voltage-source-converter (VSC), the current rating for each device in DHCC is significantly lower. The proposed system is free of shoot through and it provides system redundancy. Both simulations and experimental results are presented. Y. Wang, D. Panda, T. A. Lipo, D. Pan
2011-031 031 Robust Operation of Double-Output AC Machine Drive IEEE ECCE-Asia, Jeju Island, May 30-June3, 2011. Double-output, fault tolerance, open-winding machine, open circuit fault, short circuit fault This paper presents strategies for maintaining operation of a double-output AC machine drive in the presence of various component failures. With a short/open-switch fault, the drive is capable of operating the AC machine at a reduced power capability by creating an artificial neutral. The procedures of mode transition are shown to depend on the system configuration. This operating method can be applied to both induction and permanent magnet synchronous machines as long as they can sustain a few cycles of increased current. Robust operation of the drive in case of short-circuit fault in the phase winding is also presented. It is also demonstrated in this paper the operating method when one of the two isolated DC sources is interrupted. This work further discusses the two-phase operation mode in which one faulted phase is isolated from the remaining portion of the circuit. Simulink simulation results are presented. Y. Wang, T.A. Lipo, D. Pan
2011-032 032 Evaluation the Effect of Voltage Sags Due to Grid Balance and Unbalance Faults on DFIG Wind Turbines EPE Journal, Vol 20. No.4, Oct.2010, pp.51-61. Also in Proceedings of the International Conference on Sustainable Power Generation and Supply, 2009. SUPERGEN'09. oubly fed inductance generator (DFIG), wind turbine, balance fault, unbalance fault, voltage sag This paper demonstrated the dynamic behavior of DFIG wind turbine during grid balance and unbalance faults by using simulation results, the effect of voltage sag on DFIG wind turbine is discussed through comparing of the different voltage sag depth in a type of fault lengthways and contrasting one type of fault with another breadthwise. The response characteristics of DF1G wind turbine under PCC voltage sags are summarized by a typical example. Finally it is clear that some countermeasures on the rotor side convertor or the stator side must be taken into account for DFIG wind turbine ride through PCC extreme voltage sag. X. Yan, G. Venkataramnanan, P.S. Flannery, Y. Wang
2011-033 033 Voltage-Sag Tolerance of DFIG Wind Turbine With a Series Grid Side Passive-Impedance Network IEEE Trans. on Energu Conversion, Vol. 57, No. 4, December 2010, pp. 1048-1056. Doubly fed induction generator (DFIG), low voltage ride-through (LVRT), voltage sag ride through, wind turbine. Due to the increase of the number of wind turbines connected directly to the electric utility grid, new regulator codes have been issued that require low-voltage ride-through capability for wind turbines so that they can remain online and support the electric grid during voltage sags. Conventional ride-through techniques for the doubly fed induction generator (DFIG) architecture result in compromised control of the turbine shaft and grid current during fault events. In this paper, a series passive-impedance network at the stator side of a DFIG wind turbine is presented. It is easy to control, capable of off-line operation for high efficiency, and low cost for manufacturing and maintenance. The balanced and unbalanced fault responses of a DFIG wind turbine with a series grid side passive-impedance network are examined using computer simulations and hardware experiments. X. Yan, G. Venkataramanan, P.S. Flannery, Q. Dong, Y. Wang, B.Zhang
2011-034 034 Implementation of Sine-Wave Input/Output BLDC Inverter for Low Inductance Shipboard PM Motor Drives using Moduclar Power Platform Proceedings of the Electric Ship Technologies Symposium, Apr 2011. A 15kW Brushless DC (BLDC) motor drive system suitable shipboard applications has been developed. This platform meets shipboard interface requirements with low cost and high power density. It consists of a Pulse-Width Modulated (PWM) Current Source Rectifier (PWM-CSR) and front end Voltage Source Inverter (VSI) modules feeding a high efficiency PM Motor. Converter modules can be interchanged in order to optimize the power conversion function to the application. The design also includes controls networkability and flexibility to enable automation and end-user customization. This paper also investigates the optimal configuration in order to meet performance objectives without increasing size/weight. Experimental results are provided. W.R. Kranz, R.M. Cuzner, D.J. Drews, A.R. Bendre, G. Venkataramanan
2011-035 035 Capacitive Power Transfer for Slip Ring Replacement in Wound Field Synchronous Machines Energy Conversion Congress and Exposition (ECCE), 2011 IEEE, pp.1664-1669. Permanent magnet synchronous machines are utilized in a wide variety of applications due to their many desirable characteristics, including high torque density capability and high efficiency. In the near future, however, the demand for the permanent magnet rare earth materials is projected to exceed world production. As a result, electric machines which do not rely on rare earth materials, such as wound field synchronous machines (WFSMs), are receiving renewed attention for use in traction and wind energy applications. However, WFSMs require a current delivery mechanism to the rotor such as mechanical slip rings whose components require periodic replacement and generate adverse debris within the machine enclosure. Rotary transformers may replace slip rings but also introduce rotor speed dependencies and magnetic coupling difficulties. This paper proposes a capacitive non-contact power transfer technique to eliminate the need for mechanical slip rings while also avoiding the pitfalls of rotating transformer technologies. The capacitive power transfer system is compared to traditional rotor power coupling techniques and its performance is validated with experimental results. D.C. Ludois, K. Hanson, J.K. Reed
2012-001 001 Bidirectional High Conversion Ratio DC-DC Converter Proc. Power and Energy Conf. at Illinois, Champaign, 2012. multilevel, dc-dc, buck, boost, non-isolated, high frequency Recent trends in power conversion indicate a need for dc-dc power conversion at very high power levels and with high voltage buck/boost ratio for transmission/distribution purposes. No single conventional topology is well suited to these constraints. This paper proposes a new buck- or boost-derived multilevel nonisolated converter with superior scaling abilities. The paper derives the dynamic model in state space form, presents a suitable modulation method, and validates findings with computer simulations in MATLAB/Simulink and PLECS. J. K. Reed, G. Venkataramanan
2012-002 002 Fault Tolerant MVDC-HVAC Power Converter for Wind Farm Applications Proc.CIGRE HVDC Colloquium, San Francisco, 2012. Bridge of Bridge (BoB), M2C, Multilevel, MVDC, HVAC, Wind Farm, CSEB Recent expansion of wind farms into increasingly higher power regimes has spurred interest in alternative electrical architectures for wind farms and ac interconnections. Future wind turbines in the multiple MW range are expected to feature generation at medium voltage levels and using full electronic power conversion at each turbine. In this context, new electrical architectures may become more attractive alternatives to conventional systems. This paper proposes a converter for MVDC to HVAC conversion, realized using a novel “building block” which eliminates shoot?through faults and increases the fault tolerance of the converter as a whole. Analytical developments are validated using simulation and verified in hardware with a laboratory scale converter. J. K. Reed, G. Venkataramanan
2012-003 003 Evaluation of Magnetic Materials for Very High Frequency Power Application IEEE Transactions on Power Electronics, vol. 27, no. 1, pp. 425-435, Jan. 2012. Magnetic materials, resonant inductor, Steinmetz parameters, very high frequency (VHF). This paper investigates the loss characteristics of RF magnetic materials for power conversion applications in the 10 to 100 MHz range. A measurement method is proposed that provides a direct measurement of an inductor quality factor QL as a function of inductor current at RF frequencies, and enables indirect calculation of core loss as a function of flux density. Possible sources of error in measurement and calculation are evaluated and addressed. The proposed method is used to identify loss characteristics of several commercial RF magnetic-core materials. The loss characteristics of these materials, which have not previously been available, are illustrated and compared in tables and figures. The use of the method and data is demonstrated in the design of a magnetic-core inductor, which is applied in a 30-MHz inverter. The results of this paper are thus useful for the design of magnetic components for very high frequency applications. Y. Han, G. Cheung,A. Li, C.R. Sullivan, D.J. Perreault
2012-004 004 High Frequency Resonant SEPIC Converter with Wide Input and Output Voltage Ranges IEEE Transactions on Power Electronics, vol. 27, no. 1, pp. 189-200, Jan. 2012. This document presents a resonant SEPIC converter and control method suitable for high frequency (HF) and very high frequency (VHF) dc-dc power conversion. The proposed design features high efficiency over a wide input and output voltage range, up-and-down voltage conversion, small size, and excellent transient performance. In addition, a resonant gate drive scheme is presented which provides rapid startup and low-loss at HF and VHF frequencies. The converter regulates the output using an on-off control scheme modulating at a fixed frequency. This control method enables fast transient response and efficient light load operation while providing controlled spectral characteristics of the input and output waveforms. An experimental prototype has been built and evaluated. The prototype converter, built with two commercial vertical MOSFETs, operates at a fixed switching frequency of 20 MHz, with an input voltage range of 3.6V to 7.2V, an output voltage range of 3V to 9V and an output power rating of up to 3W. The converter achieves higher than 80% efficiency across the entire input voltage range at nominal output voltage, and maintains good efficiency across the whole operating range. J. Hu, A. D. Sagneri, J. M. Rivas, Y. Han, S. M. Davis, D. J. Perreault
2012-005 005 Design of an Electric Powertrain for a Ford F150 Crew Cab Truck Utilizing a Lithium Battery Pack and an Interior PM Synchronous Machine Drive IEEE International Transportation Electrification Conference (ITEC'12), Dearborn, MI, June 18-20, 2012. The design of an electric drive system for a Ford truck is presented. The electric drive system is designed to have similar performance to the stock truck, a 2002 model year Ford F150, with a 4.2L 150kW (peak) gasoline-powered engine. The power capabilities of lithium batteries from two manufacturers have been measured to aid in designing a battery pack that can supply sufficient voltage, power and range. A prototype interior permanent magnet (IPM) synchronous machine has been designed that can produce the desired output power with the chosen battery pack and a commercial motor controller. Dynamometer test results are provided for the machine that demonstrates a close match to the predicted performance. Additionally, the other vehicle system components that must be electrified as well as the custom data acquisition and battery management systems are described. P.J. Kollmeyer, W. Lamb, L.W. Juang, J.D. McFarland, T.M. Jahns, B. Sarlioglu
2012-006 006 Advances in AC-DC Power Conversion Topologies for More Electric Aircraft IEEE Transportation Electrification Conference and Expo (ITEC), 2012. The purpose of the paper is to review and compare the ac-dc electric power conversion topologies from the perspective of More Electric Aircraft (MEA) utilization. Advancements in power electronics encompass many evolving technologies including power semiconductor devices, microprocessors or digital signal processors (DSPs), thermal management, EMI and corona mitigation techniques, and mechanical packaging. The weight, volume, cost, and performance are critical design criteria, as is achieving other important requirements and specifications such as power quality, EMI/EMC, reliability, vibration, and shock for more electric aircraft applications. In this paper, an introduction will be made to the traditional versus modern aircraft power distribution systems illustrating the need of ac-dc power conversion systems. Then, the various power conversion topologies for more electric aircraft will be reviewed. B. Sarlioglu
2012-007 007 Reduced Magnet Designs and Position Self-Sensing Control Methods of Flux-Intensifying Permanent Magnet Synchronous Machines Proc.of SAE International, Apr.24-26, 2012, Detroit, Michigan. This paper presents advanced and cost-reducing technologies of a motor drive system with reduced permanent magnets but without a position sensor. The key enabler is the integration of novel designs of flux-intensifying interior permanentm magnet synchronous machines (FI-IPMSMs) and position self-sensing control technologies. In this paper, we focus on two advantages of FI-IPMSM over conventional fluxweakening interior permanent magnet synchronous machines (FW-IPMSMs). The first benefit is that thinner magnets are possible and there is less concern for demagnetization because of its significantly smaller flux-weakening current. This paper presents two design examples of FI-IPMSMs, one of which has not only smaller magnets but also similar power conversion capability. The second advantage is reduced saturation and cross-saturation effect, which leads to improved position self-sensing capability. However, even in the FI-IPMSM, non-ideal effects of both machine and inverter limit the position estimation accuracy. Therefore, this paper includes experimental evaluation of decoupling methods to improve position estimation accuracy. J.Tamura, C.Y. Yu, N. Limsuwan, R.D. Lorenz
2012-008 008 Concurrent Design of Interior Permanent Magnet Machines for Self- Sensing and Power Conversion IEEE Trans.On IAS-PELS Special Issues, October 2012. concurrent design, permanent magnet machine, interior permanent magnet, self-sensing, power conversion This paper presents the concurrent design of interior permanent magnet (IPM) machines for self-sensing and power conversion. Simulations with finite-element analysis are mainly used to gain insight of magnetic behavior and flux characteristics in the evaluated machines. Q-axis flux barriers are used in the concurrent rotor design due to their effective reduction in saturation effect from load current. A saliency characteristic with Ld > Lq is obtained and benefits in selfsensing and power conversion are found in the concurrent design of IPM machines. Design effects of different rotor structure parts are also evaluated. N. Limsuwan, T. Kato, R.D. Lorenz
2012-009 009 A New Course on Control of Wind Power Generation Systems Using Analysis and Simulation IEEE Symposium on Power Electronics and Machines in Wind Applications (PEMWA), July 16-18, 2012 Denver, Colorado, USA. Analysis, Control, Education Course, Education Activities, Electric Generators, Simulation, Wind Energy Generation, Wind Power Generation This paper presents a new graduate-level course that is designed, developed, and taught at the University of Wisconsin– Madison to further advance the education for wind power technologies. The objective of this course is to provide an indepth coverage of control of electric drives for wind turbines with an emphasis using state-of-the-art modeling and simulation techniques. Various generator types and their associatedm controlling techniques for wind power generation are reviewed in the course. The course begins with a thorough discussion of the performance requirements for electric power generating equipment controls in wind turbine applications. Analyses and simulations of electric generators combined with their controls are incorporated into the class curriculum to provide students with a thorough understanding of the achievable generating system performance. The course capitalizes on the student’s prior knowledge in drives, power electronics, and electric machines to develop highly skilled, advanced degree graduates that can readily become researchers or developers of nextgeneration wind power generation systems. B. Sarlioglu, D. Pan, G. Choi
2012-010 010 Machine Design Optimization Based on Finite Element Analysis in a High-Throughput Computing Environment IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. Although finite element (FE) analysis is a powerful analytical tool for electric machines, it is rarely used in iterative machine design optimization programs since it is computationally intensive, requiring excessive calculation times. This paper describes an approach for overcoming this obstacle using a high-throughput computing (HTC) environment that harnesses the parallel processing capabilities of large numbers of computers to evaluate many candidate designs simultaneously. Differential evolution has been selected as the optimization algorithm that applies FE analysis to maximize the electromagnetic performance according to an objective function in a computationally-efficient manner. This software has been applied using available HTC resources to optimize the design of a 30 kW (continuous) fractional-slot concentrated winding (FSCW) surface permanent magnet (SPM) machine for high torque density. Tests comparing the computational speeds achieved using the same optimization software with the HTC resources and a single computer have demonstrated a major reduction (approx. 30:1) of the computation time using the HTC approach. W. Jiang, T.M. Jahns, T.A. Lipo, W. Taylor, Y. Suzuki
2012-011 011 Simplified Dynamics and Control of Modular Multilevel Converter Based on a Terminal Behavioral Model IEEE-Energy Conversion & Expo Technical Conference, 2012, Raleigh, NC. Modular Multilevel Converters (MMCs) are emerging to be an attractive approach for high power applications. Equivalent circuit models and dynamic models for the MMC that provide a faithful representation of system behavior are quite complex given the large number of energy states and control variables. They are not particularly useful in studying the terminal behavior of the converter and for the development of an intuitive control approach to regulate power transfer. This paper reduces the complexity of the MMC analytical model to an equivalent boost-buck converter circuit while providing particularly insightful transparency of the converter’s physical operation from a terminal perspective. A control approach which manages throughput power as well as the MMCs internal capacitive states based on terminal quantities is developed eliminating individual feedback of module capacitor voltages to a centralized controller. An extension of the control to mitigate the circulating currents within the MMC caused by bridge voltage harmonics is also developed. The transformed boost-buck converter model and control performance are verified using simulations and experiments using a laboratory scale prototype. D. C. Ludois, G. Venkataramanan
2012-012 012 Power Density and Efficiency of System Compatible, Sine-Wave Input/Output Drives IEEE-Energy Conversion & Expo Technical Conference, 2012, Raleigh, NC. The benefits of Variable Frequency Drives (VFDs) have not been fully realized in many applications because they compete in the power density of legacy equipment, such as electro-mechanical motor controllers. This is especially the case in Navy shipboard systems where sensitive equipment is in close proximity to VFDs. In this context, this paper compares the power densities, efficiencies and costs of a Voltage Source Converter (VSC), Current Source Converter (CSC) and mixed VSC/CSC based VFDs. A meaningful comparison is made based upon an actual hardware implementation that meets stringent power quality and electromagnetic compatibility (EMC) requirements. Hardware results of a CSC/VSC based VFD are provided in order to support the findings of the study. Special consideration is given to operation at light loads. R. Cuzner, D. Drews, G. Venkataramanan
2012-013 013 Efficiency Improvement of Permanent-Split Capacitor Motors in HVAC Applications Using a Two-Phase Asymmetrical Inverter IEEE-Energy Conversion & Expo Technical Conference, 2012, Raleigh, NC. Permanent Split Capacitor motors are widely used in HVAC fan and pump applications less than 5 hp. These motors operate at efficiencies from 20% to 65%. These efficiencies can be increased if the motor is operated from a variable-frequency, variable voltage supply. However, application of power electronic controllers to realize the benefits of variable speed operation of these motors has generally been impeded due to a perceived lack of cost advantage. This paper presents a novel power converter based variable speed drive topology for the PSC motor, with appropriate dynamic efficiency control and a detailed evaluation of efficiency improvements. Simulation results that compare prior art in line-operated efficiency, and drive-operated efficiency are presented, illustrating that the proposed approach can result in efficiencies from 65% to 75%. The paper presenta hardware demonstrations and simuation results. K. Anderson, G. Venkataramanan, T. Lipo
2012-014 014 Scalability Characteristics of Magnetic Circuit Model for Fractional-Slot Concentrated Winding IPM Machines IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. Prior work has shown that it is possible to develop a magnetic circuit model (MCM) for fractional-slot concentrated winding (FSCW) interior permanent magnet (IPM) machines that captures the major sources of electromagnetic nonlinearity that are important in this type of machine. This MCM has been defined to incorporate several modularity principles in order to maximize its flexibility for different machine designs. An investigation has been carried out to evaluate the scalability characteristics of this MCM in several key dimensions including power rating, pole/slot number combinations, diameter/length aspect ratio, stator winding configuration, stator phase number, and external/internal rotor configurations. Several FSCW-IPM machine designs that have been evaluated for this scalability investigation, but one example, consisting of a direct-drive 500 kW FSCW-IPM wind turbine generator, is highlighted in this paper. Model delivers promising results as reflected in close matches between predicted flux densities, flux linkages, voltages and torque delivered by the MCM and finite element analyses. Electric machines, fractional slot concentrated winding, interior permanent magnet machines, magnetic circuit. J. K. Tangudu, T. M. Jahns
2012-015 015 Implementation of Online Battery State-of-Power and State-of-Function Estimation in Electric Vehicle Applications IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. State-of-Charge (SOC), State-of-Function (SOF), State-of-Power (SOP), electric vehicle (EV), battery management system (BMS), lithium iron phosphate battery, Kalman filter, HPPC. A method for estimating battery state-of-function (SOF) is presented with a mathematical probabilistic statement within the context of Kalman filter estimation. The traditional state-of-power (SOP) metric is replaced with an equivalent statistic that delivers the desired SOF estimate with defined variance characteristics. To reduce error in the recursive estimator, a model based on an offline test relating the opencircuit voltage (OCV) to its rate of change with battery charge is introduced that provides better temperature insensitivity than the SOC vs. OCV model typically used in literature. Experimental test results for a LiFePO4 battery with a vehicle drive cycle are used to build confidence in the estimator results. Additionally, results from the proposed estimator are compared with results from the hybrid pulse power characterization (HPPC) test and the important model assumptions are discussed. L. W. Juang, P. J. Kollmeyer, T. M. Jahns, R. D. Lorenz
2012-016 016 Improved Power Control Bandwidth of Grid- Forming Sources in a CERTS Microgrid IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. State-of-Charge (SOC), State-of-Function (SOF), State-of-Power (SOP), electric vehicle (EV), battery management system (BMS), lithium iron phosphate battery, Kalman filter, HPPC. A method for estimating battery state-of-function (SOF) is presented with a mathematical probabilistic statement within the context of Kalman filter estimation. The traditional state-of-power (SOP) metric is replaced with an equivalent statistic that delivers the desired SOF estimate with defined variance characteristics. To reduce error in the recursive estimator, a model based on an offline test relating the opencircuit voltage (OCV) to its rate of change with battery charge is introduced that provides better temperature insensitivity than the SOC vs. OCV model typically used in literature. Experimental test results for a LiFePO4 battery with a vehicle drive cycle are used to build confidence in the estimator results. Additionally, results from the proposed estimator are compared with results from the hybrid pulse power characterization (HPPC) test and the important model assumptions are discussed. M.J. Erickson, T.M. Jahns, R.H. Lasseter
2012-017 017 Power Electronics Loss Measurement using New Heat Flux Sensor based on Thermoelectric Device with Active Control IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. Grid-forming sources allow islanded operation of microgrids by providing closed-loop regulation of the microgrid voltage and frequency. Dynamic control of the voltage magnitude and frequency around their rated values provides the means for balancing the reactive power and real power using CERTS droop algorithms. Power-regulating algorithms are also applied to constrain operation within the power limits of each source, but the power regulation bandwidths are typically low because of low system damping. The limitations to increasing the power regulation bandwidth are derived, and two methods for increasing the bandwidth are introduced using either active damping or loop-shaping techniques. A combination of analysis and experimental verification are used to demonstrate the effectiveness of these techniques for raising the power control gains in order to increase the power regulation bandwidth without degrading microgrid stability. Y. Zhang, T. M. Jahns
2012-018 018 Investigation of the Rotor Demagnetization Characteristics of Interior PM Synchronous Machines during Fault Conditions IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. A new approach is presented for measuring the heat dissipation in power electronic devices using a commercial thermoelectric (TE) module as a heat flux sensor. The proposed sensor takes advantage of both the Seebeck and Peltier thermoelectric effects, yielding a new type of heat flux sensor with low thermal resistance and appealing accuracy/resolution characteristics. In order to explain the operating principles of this sensor, attention is focused on the model of the thermoelectric module and the method of controlling it as a heat flux sensor. The measured performance of early prototype versions of the sensor exhibits promising agreement with the calculated characteristics. Key performance metrics of the new heat flux sensor can be enhanced using new generations of thin-film thermoelectric modules that offer advantages compared to conventional modules using arrays of bulk TE material pellets. J. D. McFarland, T. M. Jahns
2012-019 019 PV Balancers: Concept, Architectures, and Realization IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. This paper presents a new concept of moduleintegrated converters called PV balancers for photovoltaic applications. The proposed concept enables independent maximum power point tracking (MPPT) for each module, and dramatically decreases the requirements for power converters. The power rating of a PV balancer is less than 20% of its counterparts, and the manufacturing cost is thus significantly reduced. In this paper, two architectures of PV balancers are proposed, analyzed, realized, and verified through simulation and experimental results. It is anticipated that the proposed approach will be a low-cost solution for future photovoltaic power systems. H. Zhou, J. Zhao, Y. Han
2012-020 020 Matrix Transformers for Renewable Energy Integration IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. this paper investigates the concept of using matrix transformers to achieve renewable energy integration. Matrix transformers can provide great design flexibility because they can be compatible with a variety of renewable energy sources as well as energy storage devices. Several key techniques raised by this concept are illustrated, and a high efficiency multipleinput and single output converter was designed to show how to use matrix transformers. Simulation and experimental results are presented that validate the approach presented in this paper. J. Wang, Y. Han
2012-021 021 Series Compensated Open-Winding PM Generator Wind Generation System EPE-PEMC 2012 ECCE Europe, Novi Sad, Serbia. This paper presents a new wind power generation system utilizing an open-winding permanent magnet synchronous generator (PMSG). A diode rectifier is used for the major portion of power conversion process. In addition, the proposed system controls the generated power by using an auxiliary voltage source inverter located at the neutral of the generator. The VA rating of the auxiliary inverter is only a fraction of the system rated power. Compared to wind power systems utilizing a PWM rectifier or diode rectifier having a DC/DC boost converter, the converter cost can be considerably reduced. In addition, the generator underutilization issue in a conventional diode rectifier fed wind power system can also be solved. D. Pan, T. A. Lipo
2012-022 022 Extension of the Operating Region of an IPM Motor Utilizing Series Compensation IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. This paper investigates the possibility of extending the operating region of a PM motor constrained by a given power supply voltage by using an open-winding motor drive configuration. A second inverter with a floating capacitor can be controlled to provide reactive power to the motor. A control method for the new open-winding PM machine drive employing FACTS concepts is proposed. Simulation and experimental studies on a lab scale IPM machine are presented. The results show that the proposed method is able to considerably improve the power capability of the motor beyond its base speed. D. Pan, F. Liang, Y. Wang, T. A. Lipo
2012-023 023 Design and Evaluation of a Variable-Flux Flux-Intensifying Interior Permanent Magnet Machine IEEE Trans. on Indus. Appl., Vol. 50, No. 2, Mar/Apr 2014, pp. 1015-1024. machine design, variable flux linkage, interior permanent magnet, flux-intensifying, low coercive force magnet This paper presents a design approach for interior permanent magnet (IPM) machines with variable-flux characteristics using low coercive force magnet material for improved efficiency and extended operating speed range. A flux-intensifying interior permanent (FI-IPM) type having Ld > Lq is used in the design due to positive Id operation and reduced load Iq effects. Design consideration of machine structures and variable-flux machine attributes are discussed. In addition, leakage flux in a rotor is specially designed to obtain another degree-of-freedom in variable-flux control as well. Evaluation of the designed machine is provided using FEA simulations and experimental evaluation of a proof-ofprinciple prototype machine. The designed machine shows benefits in improving efficiency and extending the range of the torque-speed map when magnetization level of the low coercive force magnet is operated at the optimal levels. N. Limsuwan, T. Kato, K. Akatsu, Robert D. Lorenz
2012-024 024 Rare Earth Reduction Using A Novel Variable Magnetomotive Force, Flux Intensified IPM Machine Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2012), Sep. 15-20, 2012, Raleigh, North Carolina, IEEE Trans. on Indus. Appl., Vol. 50 No. 3, May/June 2014, pp. 1748-1756. This paper presents a novel variable magnetomotive force, flux intensifying IPM (VFI-IPM) machine which uses only low coercive force magnets to reduce usage of rare earth metals. The VFI-IPM machine is designed with a characteristic of Ld>Lq, which is typical for FI-IPM machines, and uses low coercive force magnets with magnetization level control. A theoretical magnet operating point analysis was conducted to investigate the design methodology. A proof-ofprinciple prototype machine was then designed based on these principles. Simulation results show that the VFI-IPM prototype can achieve a wide torque-speed envelope and variable torque-speed characteristics, while not requiring high coercive force magnets that would include far more expensive rare earth materials, such as dysprosium. T. Kato, N. Limsuwan, C. Yu, K. Akatsu, R.D. Lorenz
2012-025 025 Using the Traction Drive as the Sensor to Evaluate and Track Deterioration in Electrified Vehicle Gearboxes IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. With the increase in electrified traction applications, high performance electric motor drives are now frequently coupled to gear transmissions in vehicles. It is appropriate to note that these drives have the capability to be used as a built-in sensor to estimate important characteristics of the mechanical system. The techniques to do this proposed in this paper do not require any change in the motor drive sensors, and can be performed in real time during continuously changing conditions. By estimating the states of each element as a function of its position, spatial synchronous averaging can be used on each element to identify its unique characteristics, including deterioration. This paper presents the development and evaluation of these technologies, and an exploration of the limitations of the proposed technologies. C.M. Wolf, K.M. Hanson, R.D. Lorenz, M.A. Valenzuela
2012-026 026 Time Optimal and Loss Minimizing Deadbeat-Direct Torque and Flux Control for Interior Permanent Magnet Synchronous Machines IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. This paper presents time optimal control of an interior permanent magnet synchronous machine (IPMSM) in voltage- and current- limited conditions using deadbeat-direct torque and flux control (DB-DTFC). A commanded air-gap torque and flux can be achieved by the end of each PWM period using DB-DTFC. However, it may take several PWM periods to achieve a desired torque that is physically infeasible in one step when operating near the voltage limit. The large torque command can be shaped as a feasible trajectory so that the deadbeat torque and flux is achieved for every sample time instant (switching period) along the trajectory. In this paper, the feasible trajectory is dynamically optimized to achieve a large torque command in the shortest time during voltage- and current-limited operation. Loss minimizing stator flux linkage is used during steady state operation to reduce computational complexity of the dynamic optimization and to operate the IPMSM at the loss minimizing condition. The voltage- and current-limited operation of IPMSM drives is evaluated in both simulation and experiment in this paper. J.S. Lee, R.D. Lorenz, M.A. Valenzuela
2012-027 027 Dynamic Modeling of Losses in Electrical Machines for Active Loss Control IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. This paper presents a dynamic core loss model for active loss control of permanent magnet synchronous machines. Deadbeat-direct torque and flux control (DB?DTFC) enables direct control of torque and stator flux linkage over each switching period. Total machine loss can be minimized by selecting the optimal flux level in every sampled time instant. Reliable models for dynamic copper and core loss are an essential requirement for this optimizing task. This paper presents an analytical dynamic core loss model in switching period time-domain, using stator flux linkage as the manipulated input variable. Combining numerical and analytical calculation methods is used to create an easy and practical approach to estimate core loss components based on stator flux linkage without running FEA calculations for every time instant. Additional effects like high frequency eddy current loss in electrically conducting permanent magnets as well as spatial harmonic content are taken into account. F. Quattrone, R.D. Lorenz
2012-028 028 Dynamic modelling and control of a shunt-series power flow controller based on AC-link IET Generation, Transmission & Distribution, Jan. 2012, pp. 1-11, doi:10.1049/iet-gtd.2011.0631. This study presents the dynamic modelling and proposes two control strategies for an AC-link shunt-series power flow controller (ShSPFC) based on a class of matrix converter termed vector switching converter (VeSC). This topology is intended for regulating the power flow between two buses in a power system by synthesising an adjustable voltage inserted in series to the transmission line. The study includes the principle of operation of this topology and a detailed modelling in abc and dq coordinates. Based on the dynamic model two control strategies are proposed: (i) a classical proportional integral (PI) approach and (ii) an alternative controller based on feedback linearisation (FL). These control algorithms have been compared in detailed via simulations using a benchmark power system. Results include a comprehensive analysis of the transient response owing to step changes in the reference signals and the impact on the power quality. M. Barragan-Villarejo, G. Venkataramanan, F. Mancilla-David, J.M. Maza-Ortega, A. Gomez-Exposito
2012-029 029 Dynamics and Stability of Matrix-Converter Based Permanent Magnet Wind Turbine Generator 2013 IEEE International(Industrial Electronics), Oct. 2012, Montreal, Canada. This paper proposes a boost configuration of wind turbine generation system based on matrix converters. The proposed boost configuration features i) the limitation of the voltage transfer ratio of 0.866 will not limit the terminal voltage at the stator winding under normal operating mode; and ii) low voltage ride through capability is enhanced when grid disturbances occur. The main attention of this paper is focused on the dynamics and stability issue of the matrix-converter based wind turbine generation system, which very much distinguishes itself from the systems that consist of voltage source inverters or current source inverters, where the dynamics of input and output state variables are naturally decoupled by the largeenough passive components in the dc link. Stability criterion that will guide proper design of the system is proposed and validated through numerical simulation. B. Wang, G. Venkataramanan
2012-030 030 Dynamic Loss Minimization using Improved Deadbeat-Direct Torque and Flux Control for Interior Permanent Magnet Synchronous Machines IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. Direct torque control (DTC) has become a widely acceptable alternative to field oriented control (FOC). Deadbeat-direct torque and flux control (DB-DTFC) is a significant improvement over the classical DTC methods and provides the opportunities for fast torque control and dynamic loss minimization control. The existing high switching frequency DB-DTFC solution is based on approximate discrete time models. This paper presents a low switching frequency model so that even at low switching frequencies, proper DBDTFC control can be achieved. The instantaneous dynamic loss model, which is a function of Volt-sec selection in each switching period, containing nonlinear effects such as minor hysteresis loops is theoretically derived and evaluated by both FEA simulation and experiments. With this calibrated dynamic loss model, deadbeat dynamic loss minimization control is implemented and integrated in DB-DTFC. Finally, the dynamic loss minimization control is evaluated experimentally and compared with the existing steady state loss minimization control. W. Xu, R.D. Lorenz
2012-031 031 Performance Evaluation of Interior Permanent Magnet Synchronous Machines using Deadbeat-Direct Torque Flux Control in an Indirect Matrix Converter with a Reactor Free Boost Converter IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. Indirect Matrix Converter, PWM, AC/AC converter, Over modulation, Square wave, Trapezoidal wave This paper discusses the performance of an interior permanent magnet synchronous machine by using deadbeat-direct torque flux control (DB-DTFC) in a hybrid power circuit structure, which consists of an indirect matrix converter (IMC) and a reactor free boost converter (RFBC). The first section of this paper documents the performance of DB-DTFC when carrier comparison PWM and space vector modulation (SVM) are used as modulation techniques.Corresponding Volt-sec solutions for each modulation technique are shown via simulation and experiments. The second section discusses DB-DTFC properties in the proposed IMC/RFBC circuit. The results demonstrate that DB-DTFC is capable of delivering fast dynamic torque response in one sample period even when (i) variable switching frequency is applied in the inverter of the IMC and (ii) DC offset current occurs in the output current of the IMC. G.T. Chiang, J. Itoh, J.S. Lee, R.D. Lorenz
2012-032 032 Control Method for Calculating Optimum DC Bus Voltage to Improve Drive System Efficiency in Variable DC Bus Drive Systems IEEE Energy Conversion Congress & Exposition (ECCE 2012), Sep.15-20, 2012, Raleigh, North Carolina. adjustable DC bus voltage, interior permanent magnet machines, flux-intensified IPMSM In this paper, an online method to calculate the optimum DC bus voltage in variable DC bus voltage drive system is proposed. The required DC bus voltage in the low speed region is much lower than for the rated speed region. As a result, the machine drive system efficiency can be improved with lower DC bus voltage since the switching losses in the inverter are reduced. To achieve both desired machine output torque and minimized losses simultaneously, an optimum DC bus voltage is required. However, machine parameter estimation errors and spatial harmonics in the machine result in calculation errors for the required DC bus voltage. A voltage disturbance state filter (VDSF), which is formed by a Luenburger-style closed-loop stator current vector observer with voltage command feedforward, is used to mitigate the calculation errors. Voltage errors caused by the parameter deviations and machine spatial harmonics will inherently be estimated by the observer’s state feedback controller. Therefore, calculation voltage error can be corrected by the VDSF’s disturbance voltage, so that the optimum DC bus voltage can be obtained. C. Yu, J. Tamura, R.D. Lorenz
2012-033 033 Single Sensor three phase Permanent Magnetic Synchronous Motor Drive based on Lunberger Style-Observers Proc. of Int'l Conference on Electrical Machines and Systems (ICEMS 2012), Oct. 21-24, 2012, Sapporo, Japan. dc-link current measurement, vector controlled PMSM, three phase current reconstruction, PMSM position estimation. This paper presents a technique to estimate phase currents and rotor position in a vector-controlled PMSM drive using only dc-link current measurement. Three cascaded Luenberger style observers were used to perform this task. The first one estimates phase currents and motor back emf while the other two observers estimate the rotor position and velocity. The estimated signals were compared to the actual ones and their effects on the drive performance were reported. B. Hafez, A. Abdel-Khalik, A.M.Massoud, S. Ahmed, R.D. Lorenz
2012-034 034 Concurrent Designs of Surface Permanent Magnet Machines for Self-Sensing Position Estimation and Power-Conversion IEEJ Journal of Industry Applications, Vol. 1, No. 1, pp. 1-7, 2012. self-sensing machine, sensorless control This paper presents the concurrent designs of surface permanent magnet (SPM) machines for saliency-tracking selfsensing position estimation and power-conversion. Three SPM machine design approaches are discussed from the perspectives of position estimation and power-conversion. Finite element analysis (FEA) is mainly used in this study to obtain an insight into the magnetic behaviors in SPM machines. With the appropriate design modification, SPM machines can effectively increase the saliency for the closed-loop control while preserving their power-conversion capabilities. S.C. Yang, R.D. Lorenz
2012-035 035 Impact of Active Resistance on Dynamic Power Responses in a CERTS Microgrid in Proc. of 2012 IEEE Power and Energy Conference at Illinois (PECI'12), Urbana-Champaign, IL, Sept. 2012, pp. 1-5. Active resistance, CERTS, droop, inverter, microgrid. Frequency droop algorithms used by CERTS Microgrid inverters adjust power by changing the output frequency. This concept assumes that the interconnecting impedance is primarily inductive, but it can be shown that the reactance-to-resistance (X/R) ratio significantly affects the dynamic response and the rate at which steady-state behavior is restored following transient events. The concept of active resistance is introduced as a means to accelerate the rate of convergence to steady state following a transient without the dissipative losses associated with additional line resistance. With active resistance, the damping of the system is shown to significantly increase and the stable operating region is expanded. M.J. Erickson, T.M. Jahns, R.H. Lasseter
2012-036 036 Design and Analysis of a Novel Grid-Connected to Rotor Type Doubly Fed Induction Machine IEEE Transactions on Magnetics, Vol. 48, Issue:2, February 2012 , pp. 919-922. Doubly fed induction machine, equivalent circuit analysis, finite element analysis, loading distribution method. This paper proposes a novel grid-connected to rotor type doubly fed induction machine (DFIM) in which the rotor winding is connected to the grid instead of the stator winding. The size and weight of the stator can be reduced on the proposed grid-connected to rotor type DFIM, because the proposed type can use the rotor core more efficiently compared to a conventional grid-connected to stator type DFIM. In order to verify the size and weight reduction of the proposed type, the loading distribution method (LDM) is utilized. As a design result, the outer diameter and weight of the stator on the proposed type have been decreased. Equivalent circuit analysis and finite element analysis (FEA) were performed to verify the design results and to analyze the characteristics of the novel DFIM. Finally, these analysis results are con?rmed by experimental results. Y-M You, T.A. Lipo, B-I Kwon
2012-037 037 Modeling of Novel Permanent Magnet Pole Shape SPM Motor for Reducing Torque Pulsation IEEE Transactions on Magnetics, Vol. 48, No.11, Nov. 2012. Cogging torque, linear electromagnetic torque, permanent magnet (PM) pole shape, sinusoidal back EMF, surfacemounted permanent magnet (SPM) motor. This paper deals with the modeling of a novel permanent magnet (PM) pole shape for a surface-mounted permanent magnet (SPM) motor so as to generate sinusoidal back EMF and linear electromagnetic torque. Conventional SPM motors have a square-shaped PM pole structure; therefore, square back EMF is generated along with the torque pulsations. This novel SPM motor has sinusoidal PM pole shape in the axial direction; therefore, sinusoidalback EMF is generated due to the sinusoidal magnetic flux distribution. Sinusoidal back EMF eliminates most of the cogging torque; thus, a linear electromagnetic torque is generated. Square and sinusoidal current excitation is provided as to analyze the electromagnetic torque characteristics of SPM motor models. As compared to square current excitation, sinusoidal current excitation shows better linearity as well as average electromagnetic torque for the novel SPM motor model. 3-D finite element analysis (FEA) is utilized to analyze and compare the back EMF, cogging torque, and elect omagnetic torque of conventional and proposed novel PM pole shaped SPM motor models for both square and sinusoidal current excitation. S.Q.A. Shah, T.A. Lipo, B.-I. Kwon
2012-038 038 An Improved Direct Decoupled Power Control of Doubly Fed Induction Machine Without Rotor Position Sensor and With Robustness to Parameter Variation IEEE Trans. on Energy Conversion, Vol. 27, No. 4, December 2012, pp 873-884. Component, direct decoupled power control(DDPC), direct power control (DPC), doubly fed induction generator (DFIG), doubly fed induction machine (DFIM), model reference adaptive system (MRAS), sensorless. In this paper, coupling between active and reactive powers in conventional direct power control (DPC) strategies is analyzed and a new direct DPC method for doubly fed induction machine without rotor position sensors is presented. Coupling analysis is done on an improved DPC strategy with rotor flux controllers in the stator reference frame. The presented control strategy is done by controlling the rotor flux in the grid flux reference frame. The rotor flux command is calculated using a predicted stator flux, the stator current command, and the stator resistance. Moreover, the rotor position is estimated by comparing measured and estimated values of the rotor current. Furthermore, to reduce the method’s sensitivity to the parameter inaccuracies, the mutual inductance of the machine is updated during the machine operation by the error between the magnitudes of the measured and estimated values of the rotor current. N. Amiri, S.M. Madani, T.A. Lipo, H.A. Zarchi
2012-039 039 Open-Winding Power Conversion Systems Fed by Half-Controlled Converters Energy Conversion Congress and Exposition, (ECCE), Raleigh NC, Sept. 2012. Common mode (CM), half-controlled converter, open winding. An open-winding power conversion system with two conventional six-switch voltage-source converters (VSC) affords operation with a lower volt–ampere (VA) rating of each device for a given power rating, as well as a degree of fault tolerance. The disadvantages of such a configuration include a higher total device VA rating and increased conduction loss as compared to a single Y/?-connected VSC. In certain ac–dc applications, such as telecommunications, wind, and aerospace generator drives, it is desired to have regulated input currents and output voltage, but regenerative operation is either not required or prohibited. For such applications, an alternative open-winding power converter is proposed in this paper where half-controlled converter (HCC) is employe at each end of an open-winding structure. The resultant total switch count and total VA rating are reduced by half, compared to using full bridges. Besides, the basic advantages of an open-winding con?guration, use of HCCs also guarantees immunity to dc-bus shootthrough and simplifies the gate drive circuit. The total VA rating of the proposed topology is found to be 42% less than a six-switch VSC. The operating principle, control method, and analysis with simulation and experimental results of the proposed topology in both a grid-tied recti?er application and a PM generator application are illustrated in this paper. Y. Wang, D. Panda, T.A. Lipo, D. Pan
2012-040 040 Optimal Design of a Grid-Connected to the Rotor Type Doubly Fed Induction Generator for Wind Turbine System IEEE International Magnetics Conf. (INTERMAG), Vancouver BC, May 7-11, 2012. Doubly fed induction generator (DFIG), finite element analysis (FEA), genetic algorithm (GA), Kriging model, optimal design This paper performs a shape optimization of a grid-connected-to-the-rotor type doubly fed induction generator (DFIG) in which the rotor winding is connected to the grid instead of the stator winding. To analyze the characteristics of a DFIG accurately, a time step 2D-FEA is carried out, which is coupled with Simplorer. To maximize the torque per weight as well as to maintain the efficiency, the Kriging model based on latin hypercube sampling and genetic algorithm are utilized. As an optimal design result, the torque per weight on the optimal model has been increased. Finally, the analysis and the optimal design results are confirmed by the experimental results. Y-M You, T.A. Lipo, B-I Kwon
2012-041 041 Three-Level Hysteresis Current Control for a Three-Phase Permanent Magnet Synchronous Motor Drive ECCE Asia, Harbin P.R. China, May 2012. permanent magnet synchronous motor; current hysteresis control; eight-switch inverter This paper presents a novel three-level hysteresis current control scheme for a three-phase permanent magnet synchronous motor (PMSM) fed by two single-phase four-switch voltage source inverters. Based on two-level hysteresis current control techniques for a single-phase four-switch inverter, a novel three-level PWM method for three-phase PMSM motor is implemented to reduce the magnitude and variation of the switching frequency. To obtain better harmonic performance, an improved variable band hysteresis method for three-level threephase voltage source inverter is further proposed. Considering three states of output average voltage of the inverter, a new hysteresis controller with variable band calculated by the motor resistance, inductance, DC-link voltage, phase current and backemf is designed to maintain constant phase leg switching frequencies. The proposed method is simple and effective, and verified by the simulation. H. Lin, T.A. Lipo, B-I Kwon
2012-042 042 Field Weakening of a Surface Mounted Permanent Magnet Motor by Winding Switching International Symposium on Power Electronics,Electrical Drives, Automation and Motion,2012. PM Motors, Field Weakening, High Speed Operation, Electric Vehicle. A new method for flux weakening in surface per­manent magnet (SPM) machines is proposed in this paper. This method is called winding switching technique and can reliably double the field weakening speed range of PM motors. This is significant because extending the constant power speed ratio (CPSR) of SPM machines is usually challenging task due to the presence of low-permeability surface magnets and the resulting low machine inductance. In the new method of field weakening the usual three phase motor windings are separated into two portions and each portion is connected to an inverter. The paper discusses the stator winding arrangement which allows the normal and high speed operation of the machine along with the constant output power and reports simulation results taken from Finite Element Analysis. S.Hemmati, T.A. Lipo
2012-043 043 Power-Dense Shipboard-Compatible Low-Horsepower Variable-Frequency Drives IEEE Transactions on Industry Applications, Volume: 48, Issue: 6, 2012, Page(s): 2121- 2128. Marine equipment, permanent-magnet (PM) motors, power conversion, power quality, variable-speed drives. A variable-frequency drive (VFD) having a 440-V front-end current source rectifier (CSR) interface to a voltage source inverter (VSI) feeding a Permanent-Magnet Axial-flux Air Core motor combination is a solution for low-horsepower pump and fan control that is both power dense and compatible with a shipboard environment. This paper describes the control and power platforms for the CSR/VSI and provides experimental results for a 250-V 3.3-kW system. Power density and efficiency comparisons are made between equivalent CSR/VSI- and voltagesource-conversion-based VFDs to demonstrate that the CSR/VSI-based VFD is more power dense. R. Cuzner, D. Drews, W. Kranz, A. Bendre, G. Venkataramanan
2012-044 044 Realization of an AC Link Unified Power Flow Controller Institution of Engineering and Technology Journal of Generation, Transmission & Distribution, Volume: 6, Issue: 4, 2012, Page(s): 294-302. Unified power flow controllers (UPFC) have been demonstrated to be a versatile approach for realizing ac power flow control in transmission systems. Although the conventional approach for UPFC has been based on dc link converters, direct ac link power conversion at the power frequency is being introduced as an alternative means for unified power ?ow control. In this study, the realisation of an ac link UPFC based on vector switching converters is presented. The control function that can independently control real and reactive power throughput in a transmission line is accomplished by direct ac ? ac conversion without frequency change, adopting the strategy of pulse width modulation and operated in conjunction with an appropriate configuration of typical power transformers. Operating principles, equivalent circuits, computer simulation and experimental results are presented on the basis of a laboratory-scale prototype. F. Mancilla-David, G. Venkataramanan
2012-045 045 Frequency/Sequence Selective Filters for Power Quality Improvement in a Microgrid IEEE Transactions on Smart Grid, Volume: 3, Issue: 4, 2012 , Page(s): 2039-2047. Active filters, bandpass filters, bandstop filters, digital signal processors, distributed energy resources, microgrids, negative sequence filters, positive sequence filters, voltage source inverter. A microgrid is capable of providing highly reliable power supply to sensitive loads like semiconductor fabrication or computer data processing equipment. This is especially required when the sensitive loads are located in distribution systems that also contain several single-phase and/or nonlinear loads. Voltage source inverter (VSI) based distributed energy resources can provide power quality conditioning support. They require ?lters to accurately detect unbalance and harmonics in the system. The state-of-the-art ?ltering techniques in three-phase power systems involve employing complex bandpass ?lters that pass frequencies within a band without much attenuation. Such methods however give good dynamic performance only when there is a wide separation between the desired and undesired frequencies. In power distribution systems containing imbalances and harmonic generating loads, the gap between the two frequencies may be very small, and therefore such methods don’t offer good performance. This paper proposes improved methods of ?ltering signals in three-phase, three-wire power systems, especially when there is a narrow gap between the desired and undesired frequencies. The proposed techniques contain both complex bandpass and bandstop sections and are designed on three-phase space-vector quantities. Simulation and experimental results are presented to validate these novel filtering concepts. M. llindala, G. Venkataramanan
2012-046 046 Aluminum Foil Coils for Human Scale Wind Turbines Proceedings of the 2012 IEEE Global Humanitarian Technology Conference (GHTC), 2012, Page(s): 1-5. small wind turbine; rural electrification; aluminum foil coil; axial flux permanent magnet generator A novel coil design for an axial flux permanent magnet generator to be used in small wind turbines has been realized. While traditional designs comprise enamel copper wire, the novel coil uses aluminum foil for it being low cost and readily available. Commercial home video tape is employed to provide insulation between turns, promoting the recycling of video cassettes and enhancing the magnetic properties of the generator. Three study cases were analyzed and tested; their manufacturing process and performance were recorded. The test results are presented in terms of comparison with the original copper design, indicating that aluminum foil coils have the potential to enhance the performance of the generator. The design and manufacturing approaches are unveiled so that a fabricator may redesign and build similar coils based on the materials available. P. Melendez-Vega, G. Venkataramanan
2012-047 047 High-Frequency Resonant SEPIC Converter With Wide Input and Output Voltage Ranges IEEE Transactions on power electronics, Vol.27, No.1, pp.189-200, January 2012 Class E inverter, high frequency, ON–OFF control, quasi-resonant single-ended-primary-inductor-converter (SEPIC) converter, resonant dc–dc converter, resonant gate drive, resonant recti?er, VHF integrated power converter. This paper presents a resonant single-ended-primaryinductor-converter (SEPIC) converter and control method suitable for high frequency (HF) and very high frequency (VHF) dc–dc power conversion. The proposed design provides high efficiency over a wide input and output voltage range, up-and-down voltage conversion, small size, and excellent transient performance. In addition, a resonant gate drive scheme is presented that provides rapid startup and low-loss at HF and VHF frequencies. The converter regulates the output using an ON–OFF control scheme modulating at a fixed frequency (170 kHz). This control method enables fast transient response and efficient light-load operation while providing controlled spectral characteristics of the input and output waveforms. A hysteretic override technique is also introduced which enables the converter to reject load disturbances with a bandwidth much greater than the modulation frequency, limiting output voltage disturbances to within a fixed value. An experimental prototype has been built and evaluated. The prototype converter, built with two commercial vertical MOSFETs, operates at a fixed switching frequency of 20 MHz, with an input voltage range of 3.6–7.2 V, an output voltage range of 3–9 V, and an output power rating of up to 3 W. The converter achieves higher than 80% efficiency across the entire input voltage range at nominal output voltage and maintains good efficiency across the whole operating range. J. Hu, A. D. Sagneri, J. M. Rivas, Y. Han, S. M. Davis, D. J. Perreault
2012-048 048 Evaluation of Magnetic Materials for Very High Frequency Power Applications IEEE Transactions on power electronics, Vol.27, No.1, pp.425-435, January 2012 Magnetic materials, resonant inductor, Steinmetz parameters, very high frequency (VHF). This paper investigates the loss characteristics of RF magnetic materials for power conversion applications in the 10 to 100 MHz range. A measurement method is proposed that provides a direct measurement of an inductor quality factor QL as a function of inductor current at RF frequencies, and enables indirect calculation of core loss as a function of flux density. Possible sources of error in measurement and calculation are evaluated and addressed. The proposed method is used to identify loss characteristics of several commercial RF magnetic-core materials. The loss characteristics of these materials, which have not previously been available, are illustrated and compared in tables and figures. The use of the method and data is demonstrated in the design of a magnetic-core inductor, which is applied in a 30-MHz inverter. The results of this paper are thus useful for the design of magnetic components for very high frequency applications. Y. Han, G. Cheung, A. Li, C. R. Sullivan, D. J. Perreault
2012-049 049 Inductor Design Methods With Low-Permeability RF Core Materials IEEE Transactions On Industry Applications, Vol.48, No.5, pp.1616-1627, September/October 2012 Design optimization, magnetic materials, resonant inductor, Steinmetz parameters, very high frequency (VHF). This paper presents a design procedure for inductors based on low-permeability magnetic materials, for use in very high frequency power conversion. The proposed procedure offers an easy and fast way to compare different magnetic materials based on Steinmetz parameters and quickly select the best among them, to estimate the achievable inductor quality factor and size, and to design the inductor. Approximations used in the proposed methods are discussed. Geometry optimization of magnetic-core inductors is also investigated. The proposed design procedure and methods are verified by experiments. Y. Han, D. J. Perreault
2012-050 050 Aerodynamic Fluid Bearings for Capacitive Power Transfer and Rotating Machinery Energy Conversion Congress and Exposition (ECCE), 2012 IEEE, pp. 1932-1937. Wireless power transfer (WPT) and electromechanical power conversion are traditionally accomplished with magnetic (inductive) techniques for a wide range of applications. Electrostatic (capacitive) approaches to WPT for electric machinery have had limited success over the history of power conversion due to the low power density, low mechanical robustness and cost that could not compete with magnetic steel. Recently, high frequency (kHz-MHz) power electronics have reintroduced capacitive techniques as a viable option for WPT over short distances (<2mm) and in niche rotating machinery designs. To further the practicality of capacitive techniques, capacitive coupling must be maximized. This paper proposes the use of aerodynamic fluid bearings to maximize capacitive coupling between stationary and rotating surfaces by minimizing their separation distance. This technique also allows for the estimation of mechanical system parameters such as speed. Operational characteristics and design techniques are presented and corroborated with experimental results. D.C. Ludois, J. Reed, M. Erickson
2012-051 051 Capacitive Power Transfer for Rotor Field Current in Synchronous Machines IEEE Trans. Power Electron., Vol.27, No.11, pp.4638-4645, Nov. 2012. Brushless, capacitive power transfer, noncontact, resonant converter, rotating capacitor, slip rings, wireless power transfer, wound field synchronous machine (WFSM). Permanent magnet (PM) synchronous machines are utilized in a wide variety of applications due to their many desirable characteristics, including high torque density capability and high efficiency. In the near future, however, the demand for the PM rare earth materials is projected to exceed world production. As a result, electric machines that do not rely on rare earth materials, such as wound field synchronous machines (WFSMs), are receiving renewed attention for use in traction and wind energy applications. However, WFSMs require a current delivery mechanism to the rotor such as mechanical slip rings whose components require periodic replacement and generate adverse debris within themachine enclosure. Rotary transformers may replace slip rings but also introduce rotor speed dependences andmagnetic coupling difficulties. This paper proposes a capacitive noncontact power transfer technique to eliminate the need for mechanical slip rings while also avoiding the pitfalls of rotating transformer technologies. The capacitive power transfer system is compared to traditional rotor power coupling techniques and its performance is validated with experimental results. D.C. Ludois, J.K. Reed, K. Hanson
2012-052 052 Modular Multilevel Converter as a Low Inductance Machine Drive in Power and Energy Conference at Illinois (PECI), 2012 IEEE , vol., no., pp.1-4, 24-25 Feb. 2012. Many high performance machines are high speed, use permanent magnets, and have a low turns number in conjunction with minimal to no iron. Under these circumstances, the inductance of the machine is very low, i.e. the design of a voltage sourced power electronics drive is challenging from a current regulation/ripple perspective. Traditional approaches to correct this issue include external line reactors between the drive and machine or high switching frequencies. Implemented individually, these techniques are not optimal as external reactors may be bulky and high switching frequencies may cause additional losses in the drive and degrade the mechanical structure of the machine via parasitic coupling. This paper presents the use of a modular multilevel converter (MMC) to drive a low inductance machine. The MMC topology is unique via its ability to combine the operational characteristics of voltage and current source converter topologies to drive zero inductance loads while regulating current. D.C. Ludois, G. Venkataramanan
2013-001 001 Surface Spiral Coil Design Methodologies for High Efficiency, High Power, Low Flux Density, Large Air-Gap Wireless Power Transfer Systems in Proc. of the Applied Power Electronics Conference (APEC), Long Beach, CA, March 17-21, 2013. It was demonstrated that a surface spiral winding coil has low skin- and proximity effect losses in MHz, high power wireless power transfer systems. However, it was not clearly explained why the surface spiral winding coil is appropriate to use in kW level, low flux density, and safe wireless power transfer systems. Furthermore, research has not focused on the losses of a dielectric substrate of a surface spiral winding coil, even though the dielectric loss can overwhelm the skin- and proximity effect losses at MHz frequencies. In the first part of this paper, the benefits of the surface spiral winding coils for large air-gap, kW level wireless power transfer systems are discussed. In the following section, various sources of the power dissipation in surface spiral coils are identified. The discussion focuses on the dielectric losses in the substrates of surface spiral winding coils. Low-loss substrate design guidelines are proposed using the investigation results. The proposed design guidelines are evaluated by means of FEA simulation. S.H. Lee, R.D. Lorenz
2013-002 002 Observer-Based Estimation of Modulus of Elasticity for Papermaking Process Proc. of IEEE IAS Pulp & Paper Industry Conf., June 23-27, 2013, Charlotte, NC. modulus of elasticity, paper machine, adaptive observer. Real-time estimation of the modulus of elasticity (E) in paper machines would enable it to be controlled, improving final product quality and reducing the occurrence of sheet breaks. This paper develops a novel topology to estimate E on web machines based on an adaptive observer structure that combines model reference adaptive control (MRAC) with a closed loop observer using field signals such as tension force, velocity/position and torque. The evaluation of the proposed topology is performed on the dryer-calender span of the dry-end section of a (LWC) paper machine. Results show a fast and accurate estimation of E, confirming the robustness of the adaptive observer structure. G. Ramirez, R.D. Lorenz, M.A. Valenzuela,
2013-003 003 Generalized Correlations for the Estimation of Condensate Torque and Power in Dryer Cylinders Proc. of IEEE IAS Pulp & Paper Industry Conf., June 23-27, 2013, Charlotte, NC, IEEE Trans. on Indus. Appl., Vol. 50 No. 3, May/June 2014, pp. 1678-1686. paper machine, dryer cylinders, condensate observer, power requirements. Condensate accumulated inside dryer cylinders will produce an increased power demand and eventually the inability of the dryer drive to accelerate the section. In a previous paper these authors presented an online estimation algorithm capable of detecting the presence of condensate during a section starting. In this paper a complete set of tests is run over two experimental cylinders covering up to 40% of cylinder volumes and the complete set of power curves are reported and analyzed. Specifically, the presence of a combined cascading – rimming region in the medium to high condensate loads is confirmed. This combined mode modifies the pattern followed by the maximum power in the low condensate region. Using this data, high-order and simplified correlations are proposed for the estimation of condensate in flooded dryer cylinders. These new correlations increase the capacity of the online estimation algorithm to give good estimations of the condensate load present inside the dryer cylinders up to 55 mm of rim thickness. G. Ramirez, M.A. Valenzuela, R.D. Lorenz
2013-004 004 Estimation of Condensate inside Dryer Cylinders during Section Shutdown Proc. of IEEE IAS Pulp & Paper Industry Conf., June 23-27, 2013, Charlotte, NC, IEEE Trans. on Indus. Appl., Vol. 50 No. 3, May/June 2014, pp. 1668-1677. paper machine, dryer cylinders, condensate observer, power requirements. The presence of condensate inside the dryer cylinders produce a significant increase in the power requirements during starting putting at risk the capacity of the drive to complete a successful start. In past papers authors developed estimation algorithms for the detection of condensate during section starting. This paper proposes and evaluates a new strategy that will complement the previous algorithms. This strategy will detect the presence of condensate from the condensate collapsing during the section shutdown. Proposed correlations are derived through a complete experimental evaluation in two experimental cylinders covering rim thicknesses up to 55 mm. The estimation algorithms are split in a low/moderate condensate load zone, and in a high condensate load zone. Results confirm the robustness and accuracy of the proposed algorithms. M.A. Valenzuela, J.M. Bentley, R.D. Lorenz
2013-005 005 Suggested Design Space in a PMSM Parameter Plane for Variable Flux Machines Proc. of Int'l Electric Machines and Drives Conf (IEMDC), May 12-15, 2013, Chicago, IL. variable flux machine, variable flux linkage interior permanent magnet, PMSM parameter plane, fluxintensifying In this paper, design space for variable flux (VF) machines is examined in a permanent magnet synchronous machine (PMSM) parameter plane based on constant parameter, lossless power conversion properties, and estimated total loss distributions (i.e. copper and iron losses) while applying a d-axis current constraint based on an assumed demagnetization characteristic. Medium-to-high speed, partial torque operation is typical for duty cycle loads, such as in the case of the electric vehicle. VF machines can reduce losses in these operating conditions by reducing the internal magnetization state of the magnet, thereby reducing flux linkage associated with flux produced by the magnet. In this paper, VF machines with large normalized permanent magnet flux linkage which are in the highly salient, flux intensified (FI) machine design space (VFIIPMs) are shown to have large maximum torque, rated power, inverter utilization, and constant power speed ratio (CPSR) as well as low losses in the low torque region over a wide speed range when compared to conventional fixed magnet flux PMSMs. B. Gagas, T. Fukushige, N. Limsuwan, C.Y. Yu, K. Akatsu, R.D. Lorenz
2013-006 006 Reduced Parameter Sensitivity Stator Flux Linkage Observer in Deadbeat-Direct Torque and Flux Control for IPMSMs. Proc. of Int'l Electric Machines and Drives Conf (IEMDC), May 12-15, 2013, Chicago, IL. Direct torque control (DTC) has become a widely acceptable alternative to field oriented control (FOC). Deadbeatdirect torque and flux control (DB-DTFC)is a significant improvement over the classical DTC methods and provides the opportunities for fast simultaneous control of torque and dynamic loss minimization. DB-DTFC uses estimated torque and stator flux magnitude from a stator flux observer as feedback. The constant parameter state observer utilizes the system model to estimate immeasurable physical states or dynamics of the real system. However, the constant parameter stator flux observer is parameter sensitive at low frequencies. This paper presents a flux observer that utilizes disturbance input decoupling (DID) so that even under varying or inaccurately identified machine parameters, stator flux linkage and torque can be accurately estimated. The structure of the DID flux observer is theoretically derived and discussed. The flux estimation error due to the parameter variations is decoupled through the disturbance information from a stator current observer. Comparative evaluation of the DID flux observer versus the constant parameter flux observer has been performed via both simulation and experiments. W. Xu, R.D. Lorenz
2013-007 007 Integration of GMR's in Power Electronic Package Layout to Achieve Multifunctional Sensing Proc. of the Magnetoresistive Sensors and Magnetic Systems Symposium, March 19-20, 2013, Wetzlar, Germany, pp. 2-9. The spatially varying magnetic field within a power electronics package contains information of the semiconductor junction temperature and strain, and the interconnect currents, temperature, displacement, and strain. By integrating GMR detectors into the package, the field can be measured, and these signals can be decoupled for control feedback. The barriers to integrating GMRs into semiconductor packaging are discussed along with proposed solutions. The design of semiconductor interconnects for high bandwidth current and strain sensing is investigated using finite element analysis (FEA) and verified by experimental results. High bandwidth (10MHz) current sensing was achieved by interconnect design based field shaping and concentration. This high bandwidth current sensing enables junction temperature estimation. A displacement sensing resolution of 0.6 µm was achieved by eddy current based high frequency field shaping. This high displacement sensing resolution enables accurate interconnect strain estimation. J.D Hoffman, B.A. Dow, R.D. Lorenz
2013-008 008 Efficiency Comparison of SiC and Si-Based Bidirectional DC-DC Converters IEEE Transportation Electrification Conference and Expo (ITEC), Detroit, Michigan, June 16-19, 2013. silicon-carbide power devices; bidirectional DCDC converter; electric vehicle; hybrid vehicle; loss calculation; efficiency With the advancement of technology on wide band gap materials such as silicon-carbide (SiC), there are now better choices of SiC power devices available than ever before. It is widely known that SiC-based switching devices provide significant performance improvements on many aspects including lower power dissipation, higher operating temperatures, and faster switching frequencies compared to conventional Si devices. However, the tremendous benefits of SiC devices have not yet been fully explored by researchers. In this paper, a popular topology of bidirectional DC-DC converter that is suitable for hybrid vehicle or electric vehicle applications is considered. Comparative analyses regarding the power loss reductions of power devices and efficiency improvements are carried out for the converter based on three sets of device combinations, e.g. all-silicon (conventional silicon IGBTs and diodes), hybrid (silicon IGBTs with SiC Schottky diodes), and all-SiC (SiC MOSFETs with SiC Schottky diodes). D.Han, J.Noppakunkajorn, B.Sarlioglu
2013-009 009 Development of Efficient Electromagnetic-Thermal Coupled Model of Electric Machines based on Finite Element Analysis in Proc. of 2013 IEEE Intl. Electric Machines and Drives Conf. (IEMDC'13), Chicago, May 2013. Multi-physics optimization of an electrical machine design requires that its electromagnetic (EM) and thermal performance must be analyzed and optimized simultaneously since electric machines are heavily constrained by thermal limits. This paper presents the development of coupled models for the EM and thermal finite element (FE) analysis of electrical machines. Temperature-dependent material properties are used so that temperatures inside the machine can be predicted simultaneously with the EM performance. Three 30 kW fractional-slot concentrated winding surface PM machines optimized for maximum torque density, minimum cost, and maximum efficiency have been investigated in order to demonstrate this approach. The results show that the coupled EM/thermal models provide an efficient means of determining the maximum steady-state current density for electric machines that will meet predefined thermal constraints and avoid demagnetization of the rotor magnets. A procedure for efficiently identifying the maximum allowable current density using numerical methods is presented. W. Jiang, T.M. Jahns
2013-010 010 Design of Electric Machines for Electric Vehicles based on Driving Schedules in Proc. of 2013 IEEE Intl. Electric Machines and Drives Conf.(IEMDC'13), Chicago, May 2013. Electric machines, fractional-slot concentrated windings, distributed windings, interior permanent magnet (IPM) synchronous machines, electric vehicles This paper presents a specialized design evaluation tool for electric machines intended for use in electric vehicles that seeks to maximize the machine’s efficiency in the operating regions that most closely correspond to the vehicle’s driving schedules. The influences of different designs on a production battery-electric vehicle are studied. A combination of closed form and finite element analysis is applied in the design process to incorporate both vehicle driving patterns and machine electromagnetic characteristics in order to optimize the machine efficiency optimization in the most frequent operating regions. The total required energy and relative losses of each of the candidate machines is calculated for the driving cycles using the predicted machine and vehicle performance characteristics. Finally, the Nissan Leaf's energy consumption is calculated using simplified combined city/highway driving schedules and compared to the EPA's published range, demonstrating that the developed analytical model can deliver promising accuracy. G. Choi, T.M. Jahns
2013-011 011 Pulsewidth-Modulated Dual-Half-Controlled Converter IEEE Transactions on Power Electronics, Vol. 28, No.2, February 2013. The dual-half-controlled-converter (DHCC) is a voltage-source active recti?er which can be considered as a potential alternative to the conventional three-phase six-switch boost recti?er. The DHCC is attractive due to its lower component current rating, immunity to shoot-through, simpler gate drive circuitry, lower semiconductor losses, and fault redundancy. Compared to a six-switch voltage-source-converter and a diode recti?er with a shunt active ?lter, DHCC presents some advantages and has good potentials for grid-tied and generator-tied applications. In the previous literature, the DHCC was controlled through a hysteresis regulator. This paper discusses in detail the current compensation and harmonic cancellation methodologies and presents improved control techniques for the three-phase three-wire DHCC using interleaved pulsewidth modulation (PWM). Compared with the existing hysteresis controller, the proposed ?xed-frequency PWM controllers require smaller ?ltering elements and/or a lower sampling frequency. Both simulation and experimental results are presented to demonstrate the superiority of the proposed PWM control algorithm. The impacts of input reactor sizing and dc-link voltage rating are analyzed and discussed. Y. Wang, D. Panda, T.A. Lipo, D. Pan
2013-012 012 Integration of Point Field Detectors Within Power Electronic Packages to Achieve Multifunctional Sensing Proc. of ASME International Technical Conf. and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems (InterPACK), July 16-18, 2013, Burlingame, CA. The spatially varying magnetic field within a power electronics package contains information of the semiconductor junction temperature and the interconnect currents, temperature, displacement, and strain. The design of semiconductor interconnects for point field detector based highbandwidth current and strain sensing is investigated using finite element analysis (FEA) and verified by experimental results. High bandwidth (10MHz) current sensing was achieved by interconnect design based field shaping and concentration. A displacement sensing resolution of 0.6 µm was achieved by eddy current based high frequency field shaping. Design methodologies to achieve this multifunctional integration of sensing are the primary new contribution of this work. J.D. Hoffman, B.A. Dow, R.D. Lorenz
2013-013 013 High Efficiency, MHz Frequency, Resonant Converter for Sub-meter (30cm) Distance Wireless Power Transfer Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2012, Denver, CO. This work investigates efficient power converters for MHz frequency wireless power transfer. MHz operation is used to reduce the magnetic field strength to very low levels in the space between the coils. A design methodology is developed for the selection of the power amplifier topology along with the resonant tank compensation for the transmitting and receiving coils. The Class E power amplifier with a series-series resonant tank configuration is selected for the design of a 50 W, 30 cm air gap, 3.45 MHz wireless power transfer system with a system level peak efficiency of over 80%. The design is verified via simulation and methods for manipulating the output power are compared. A physical system is built to better understand the challenges specific to the MHz frequency power converter for wireless systems. An experimental evaluation of system performance and design limitations is presented. R. Calder, S.H. Lee, R.D. Lorenz
2013-014 014 Robustness analysis of deadbeat, direct torque and flux control for IPMSM drives Proc. of European Power Electronics (EPE 2013), Sept. 3-5, 2013, Lille, France. Permanent magnet motor, direct torque and flux control, robustness, control of drive This paper presents robustness evaluation of deadbeat-direct torque and flux control (DB-DTFC) of IPMSM drives with respect to machine parameter variation. For performance comparison, current vector control (CVC), one of the most widely used control methods, is also implemented under identical operating conditions as DB-DTFC. As the metrics to evaluate dynamic performance of DBDTFC and CVC IPMSM drives, command tracking is used to investigate torque command tracking performance and dynamics stiffness is used to evaluate disturbance rejection performance. In addition, the torque estimation accuracy of DB-DTFC and CVC is investigated with respect to parameter variation. Simulation and experimental results of robustness evaluation of DB-DTFC and CVC are presented in this paper. Furthermore, the dynamic robustness of DB-DTFC and CVC drives are evaluated via eigenvalue (EV) migration. Since an IPMSM drive is a nonlinear system, an operating point model of an IPMSM drive is derived for linear analysis of EV migration. Finally, the US06 Supplemental Federal Test Procedure (SFTP) automotive driving cycle is applied to investigate the EV migration of a test IPMSM drive over a wide operating space. J.S. Lee, R.D. Lorenz
2013-015 015 Efficiency Contours and Loss Minimization over a Driving Cycle of a Variable-Flux Flux-Intensifying Interior Permanent Magnet Machine Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. In this paper, experimental evaluations for the efficiency of a novel interior permanent magnet (IPM) machine with variable-flux characteristics using low coercive force magnets is presented. The variable-flux characteristics allow improving the efficiency of machine and also reducing the usage of rare-earth material in the high-coercive magnets, which are currently used for the IPM machines in electrified vehicles. A flux-intensifying interior permanent magnet (FIIPM) type having positive saliency is employedfor a positive daxis current to mitigate a demagnetizing field in the magnet due to a q-axis current. A proof-of-principle machine is designed, fabricated and evaluated. A series of experiments are conducted to capture the efficiency contours with different magnetization states of the low coercive force magnets. The designed machine shows benefits in improving efficiency when the magnetization state is optimally operated. With these results, the loss over a driving cycle is then simulated and the benefits of changing the magnetization state are quantified. T. Fukushige, N. Limsuwan,T.Kato, K. Akatsu, R.D. Lorenz
2013-016 016 Sensing Power MOSFET Junction Temperature Using Circuit Output Current Ringing Decay Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. Junction temperature sensing requirements for fast MOSFET junction temperature control and high power fast switching power converter protection are not easily met with non-intrusive techniques. This paper presents a non-invasive circuit model-based sensing method suitable for a high bandwidth, hard-switching converter power MOSFET junction temperature estimation without any additional temperature detector. For the purpose of demonstrating MOSFET junction temperature sensing, a chopper circuit is used. The ringing superimposed with a circuit load current is used for MOSFET junction temperature estimation. A ‘gate drive-RDS-on-L-C’ resonant model is implemented indicating the mechanism of power MOSFET turn-on dynamics. Modeling includes the gate-drive output parasitics, power MOSFET intrinsic parameters, PCB parasitics and load parasitics. To evaluate the methodology, LTSpice Simulation and experimental results are studied. H. Niu, R.D. Lorenz
2013-017 017 High Frequency Injection-based Parameter Identification for DB-DTFC Implementation on IPMSMs Considering Cross-Saturation Effects Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. Deadbeat-direct torque and flux control (DBDTFC) has demonstrated several technical advantages over classical hysteresis DTC and PI regulator based direct torque control (DTC) methods. These include fast torque control, low ripple, easily integrated dynamic loss minimization control, and one control law that uses the inherent Volt-sec. source properties of power electronics to enable operation over all operating conditions including voltage limits. DB-DTFC uses the fundamental machine model to form the inverse solution for Volt-sec selection at each switching period. Therefore, DBDTFC is a model-based discrete timecontroller that relies on accurate machine parameter estimation to provide accurate dynamic torque control. In this paper, a new method for high frequency injection-based real-time self- and mutual inductance estimation is proposed and evaluated in both simulations and experiments. In this new method, the estimated inductances including cross-coupling inductance due to cross-saturation are then used to estimate the stator resistance and permanent magnet flux linkage. The stator flux linkage observer using the identified machine parameters, yields improved stator flux linkage estimates that enable precise torque calculation. Experimental evaluation of the HFI-based flux estimates on torque estimation and control accuracy is performed at an IPMSM drive test bench with torque transducer mounted. W. Xu, R.D. Lorenz
2013-018 018 Design Methodology for Variable-Flux, Flux-Intensifying Interior Permanent Magnet Machines for an Electric-Vehicle-Class Inverter Rating Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. This paper presents a design methodology for variable-flux, flux-intensifying interior permanent magnet (VFI-IPM) machines for a 30 kW electric vehicle class inverter rating requirement. Feasible VFI-IPM design considering current in operating range limits of 1 pu is a design objective. Positive Id vector control with positive reluctance torque, resulted from having Ld > Lq, under loaded conditions and magnetization state changes within 1 pu current (defined at continuous current rating) are primary constraints. Analytical relationships between magnet size, rotor and stator design parameters are used to facilitate a feasible design. Impact of design parameters on machine torque capability and saliency characteristics is evaluated. N. Limsuwan, T. Fukushige, K. Akatsu, R.D. Lorenz
2013-019 019 Using Loss Location and Loss Magnitude Manipulation for Slip Gain Tuning in Field Oriented Induction Machine Controllers Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. This work investigates loss location and loss magnitude manipulation via slip gain tuning in indirect field oriented induction machine drives. By using finite element analysis (FEA), the spatial distribution of the losses and the extent to which the distribution is manipulated via control tuning of the slip gain is investigated. Practical slip gain tuning variations across the full operating range, such as low speed when convection-based heat transfer is less effective, as well as high speed, are investigated. In addition, the dynamic performance corresponding to loss location manipulation tuning is investigated and documented. In this work, it is seen that using inadequate slip gain for field orientation reduces the total rotor losses within the machine. There is an opportunity to balance the shift of rotor loss to stator loss with the marginal degradation in torque dynamic performance when the slip gain is reduced for loss location manipulation. This work leads to a systematic method for understanding how loss location and magnitude change as a function of indirect field oriented controller tuning, with a goal of expanding the controller tuning paradigm to add a loss location objective to the classical dynamic torque performance objective. M. Kringle, R.D. Lorenz
2013-020 020 Deadbeat, direct torque and flux control of IPMSM drives using a minimum time ramp trajectory method at voltage and current limits Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. This paper presents the voltage and current limited operation of an interior permanent magnet synchronous machine (IPMSM) using deadbeat, direct torque and flux control (DB-DTFC). A commanded air-gap torque and stator flux can be achieved by the end of each PWM period using DBDTFC. However, it may take several PWMperiods to achieve a desired air-gap torque that is physically infeasible in one step due to voltage limits. In that case, the torque and flux command trajectories operating over multiple periods can be developed to achieve deadbeat torque and flux response for every PWM period. The torque and flux command trajectories can be developed in different shapes depending on desired objectives. In this paper, a minimum time ramp trajectory method is proposed to achieve both simple real time implementation and fast and stable transient dynamics of IPMSM drives. Simulation and experimental results for the minimum time ramp trajectory method for an IPMSM drive are presented. J.S. Lee, R.D. Lorenz
2013-021 021 Digital Implementation of Deadbeat-Direct Torque and Flux Control on Low Switching Frequency Induction Machine Drives Using Enhanced Flux Observer and Improved Torque Model Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. This paper presents a digital implementation of deadbeat-direct torque and flux control (DB-DTFC) for induction machines at low switching frequencies. For high switching frequencies, existing discrete time flux observers and Volt-sec.-based inverse torque models used for DB-DTFC achieve acceptable flux estimation accuracy and fast torque response. However, the flux estimate is less accurate when switching frequency is reduced and DB-DTFC performance degrades. This paper develops a more suitable flux observer and Volt-sec.-based inverse torque model that minimizes flux estimation error and improves torque control for DB-DTFC. Simulation and experimental results are provided to evaluate the performance of the proposed observer and torque model at very low switching frequencies. Consequently, digital implementation of low switching frequency DB-DTFC on high power induction machines is feasible. Y.K. Wang, S. Tobayashi, R.D. Lorenz
2013-022 022 Variable flux machine torque estimation and pulsating torque mitigation during magnetization state manipulation Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. This paper focuses on dynamic control, under loaded conditions, of the magnetization state of suitably designed variable flux (VF) permanent magnet (PM) machines. Such VF-PM machines have been shown to achieve low loss operation over a wide range of load and speed. For this type of machine, the PM flux linkage varies during the magnetization manipulation process. Published magnetization techniques have occurred at zero load conditions and thus did not generate torque pulsations. However, under loaded conditions, the existing methods would produce unwanted torque pulsation. This paper proposes a parameter insensitive method to solve this issue. This method generates a decoupling current command which is calculated from accurately estimated stator flux linkage. Accurate flux estimation, i.e. insensitive to inductance saturation and PM flux linkage variation (e.g. temperature or magnetization level) is achieved by using the voltage disturbance estimated by a closed-loop stator current vector observer. In both simulations and experiments, it is shown that even during magnetization processes under loaded conditions, the flux can be estimated correctly and smooth torque output can be achieved. C.Y. Yu, T. Fukushige, N. Limsuwan, D. Reigosa, R.D. Lorenz
2013-023 023 A Transient Core Loss Calculation Algorithm for Soft Magnetic Composite Material Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. In order to investigate the feasibility of dynamic loss minimization for DC-to-DC converters by control methods, transient core loss analysis for soft magnetic composite material is presented in this paper. A practical calculation model based on equivalent elliptical loop (EEL) model is developed to obtain the transient losses, and the algorithm is modified to adapt to non-sinusoidal waveforms by checking inflection points of the magnetic flux trajectory. With this model, time domain information of trajectories can be calculated automatically. And because of the simplicity of this model, it is easy to apply the calculation to finite element analysis. In experiments, a 200 Hz sinusoidal wave and also the 200 Hz wave combined with a single odd harmonic (3rd, 5th, …49th) are applied to a ring core made of one-percent SiFe alloy powder and used to evaluate and document accuracy. M. Wasekura, C.M. Wang, Y. Maeda, R.D. Lorenz
2013-024 024 Analysis of Pulsating Torque in Squirrel Cage Induction Machines by Investigating Stator Slot and Rotor Bar Dimensions for Traction Applications Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. The purpose of this paper is to analyze the pulsating torque in squirrel cage induction machines by studying the stator slot and rotor bar dimensions. To mitigate the pulsating torque produced by the non-sinusoidal spatial distribution of magnetomotive force (MMF) and permeance in the air-gap, design options are evaluated at various stator and rotor slot dimensions and operating conditions. Analytical and finite element analyses are conducted to evaluate the influences of changing slot dimensions to the output average and ripple torque. Design trade-offs are also discussed in the end. Y. Li, Silong Li, B. Sarlioglu
2013-025 025 Core Loss Estimation of High Speed Electric Machines: An Assessment IEEE, IECON, Vienna, Austria, November, 10-13, 2013 Core loss, high speed electric machines, modified Steinmetz equations, flux density at high frequency High speed electric machines have been gaining significant interest over the last several years. This is mainly due to several advantages including increased power density and lower cost. High speed machines can allow for the elimination of gear box to achieve higher reliability and reduced maintenance of the full drive system. One of the challenges with designing high speed machine is accurate estimation of core loss. This paper will introduce both opportunities and challenges of estimating core loss for high speed electric machines. First, this paper will summarize core loss characterization and modeling based on physical and mathematical formulation. The limitation of classical Steinmetz equation is explained and a modified Steinmetz equation with variable coefficients is presented to improve accuracy of the core loss estimation for wide frequency and flux density range. Several contributing factors are also reviewed for estimation of core loss with consideration of arbitrary excitation waveform, flux density distribution, and the skin effect. This paper explains a core loss model for permanent magnet electric machines and discusses the dependency of core loss on machine dimensions as well. Finally, future opportunities are suggested for core loss estimation of high speed machines. W. Choi, S. Li, B. Sarlioglu
2013-026 026 Analysis of a SiC Three-Phase Voltage Source Inverter Under Various Current and Power Factor Operations IEEE, IECON, Vienna, Austria, November, 10-13, 2013 silicon carbide power devices; three-phase voltage source inverter; semiconductor loss; efficiency; wide bandgap semiconductors Due to the superior physical properties of Silicon Carbide (SiC) material, SiC MOSFETs and Schottky diodes are becoming available for voltages higher than 600 V, which has been dominated by conventional silicon (Si) IGBTs and P-N diodes. Compared to the Si devices, SiC devices excel in many areas such as faster switching speed, lower conduction and switching losses, and higher temperature capability. This paper thoroughly investigates the performance of a 12 kVA SiC-based three-phase voltage source inverter in simulation. The proposed inverter is first compared with a conventional Si inverter of the same rating under given loading conditions. In addition, high frequency operations up to 100 kHz are investigated. Finally, the SiC inverter is evaluated for different load currents and power factor angles. Loss and efficiency values for each case are calculated and reported. D. Han, J. Noppakunkajorn, B. Sarlioglu
2013-027 027 Design of Axial Flux Permanent Magnet Machine for Marine Current Turbine IEEE, IECON, Vienna, Austria, November, 10-13, 2013 axial flux machine; torus machine; machine design; permanent magnet; marine current turbine; double rotor; direct drive; This paper presents an analytical analysis and application of axial flux permanent magnet machine design to marine current turbine. Marine current is a prominent renewable energy source because of its predictable current profile. Rim-driven, direct-drive type is favorable for the marine current turbine application in terms of maintenance and reliability. The axial flux permanent magnet machine is a candidate machine type that not only reduces machine manufacturing costs, but also achieves high performance. The general sizing equation technique is implemented to produce the machine size. The magnetic flux relationship among air gap, stator yoke, rotor yoke, and permanent magnet is taken into account to calculate core material size of the machine. FEA simulation results are compared with analytical calculations. The proposed machine and the reference machine design results are briefly compared. Moreover, machine cost is estimated based on the volume of the proposed machine. J.H. Kim, B. Sarlioglu
2013-028 028 Observer Based Active Damping of LCL Resonance in Grid Connected Voltage Source Converters Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. Voltage source converters (VSC) with LCL filters are attractive in grid connected applications because they greatly reduce pollution of the utility voltage due to switching harmonics. However, LCL network has very low impedance at frequencies close to resonance and therefore even small voltage magnitudes at those frequencies can excite currents of large magnitudes or even cause instability. In this paper novel current controller structure is proposed that uses Luenberger observer as a sensor replacement and state predictor to predict filter capacitor current which is passed through virtual resistor to create damping effect. Predicted filter capacitor through virtual resistor is inner fast loop, while outer loop with appropriate feedforward terms ensures fast command tracking and zero steady-state error. The use of the observer alleviates the impact of sampling delay which greatly improves active damping capability and eliminates the need for additional sensors. This paper with simulation and experimental results demonstrates true active damping and the effectiveness of the virtual resistance in actively stiffening input impedance of AFE drive at frequencies close to resonance. V. Miskovic, V. Blasko, T.M. Jahns, A. Smith, C. Romenesko
2013-029 029 Analysis of Stator Iron Loss in Interior PM Machines under Open and Short-Circuit Conditions Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. This paper describes an analytical approach for calculating the stator iron loss for multiple-barrier interior permanent magnet (IPM) machines with distributed windings, under open and short-circuit (deep field-weakening) conditions. It is based on using a lumped equivalent-circuit model to predict the rotor mmf and then the harmonic components of the airgap flux density. A “filter function” approach is used to calculate the stator tooth and yoke flux densities and hence iron loss components. It provides an insightful means for visualizing the effect of stator and rotor design changes on the stator iron losses. The analytical stator iron loss predictions for four IPM machine configurations are compared with finite element results. C. Tang, W.L. Soong, G.S. Liew, N. Ertugrul, T.M. Jahns
2013-030 030 Influence of d- and q -Axis Currents on Demagnetization in PM Synchronous Machines Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. This paper investigates the influence of d- and q- axis current components on the static demagnetization behavior of permanent ma g net (PM) synchronous machines. Finite element (FE) analysis is used to analyze and simulate the behavior of an interior permanent magnet (IPM) machine. The flux density is recorded at several points inside the magnets for various magnitudes of both d- and q- axis current and compared to a threshold value that would result in irreversible demagnetization. Both current components are found to have a significant influence on the demagnetization behavior of the permanent magnets, particularly in the regions that are most at risk for demagnetization. Results show that q- axis current supplied to the machine under some circumstances can offset the de grading effect of d- axis current that would otherwise result in demagnetization. Similar trends are exhibited in IPM machines with both rare-earth and ferrite magnets. Implications of this current component interaction for reducing ma g net vulnerability to demagnetization are examined to better understand the opportunities to use it constructively in the design future IPM machines and control strategies with improved electromagnetic robustness. J.D. McFarland, T.M. Jahns
2013-031 031 Interior Permanent Magnet Synchronous Machine Rotor Demagnetization Characteristics under Fault Conditions Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. This paper presents the dynamic response of an interior permanent magnet synchronous machine (IPMSM) drive to various fault conditions and their effects on the PM demagnetization characteristics. Attention is focused on modeling the IPMSM drive including nonlinear magnetic behavior under asymmetrical inverter fault conditions, demonstrating the significant risks of irreversible demagnetization caused by the large transient fault currents. Other types of inverter faults are discussed, including phase-leg open-circuit fault and uncontrolled generator (UCG) mode fault. Finite element (FE) analysis is used to simulate the demagnetization characteristics under a variety of fault conditions. Three-phase symmetrical short circuit fault characteristics for several different IPM machine designs are discussed. G. Choi., T.M. Jahns
2013-032 032 Coupled Electromagnetic-Thermal Analysis of Electric Machines Including Transient Operation Based on Finite Element Techniques Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. Since the mass and volume of electric machines are heavily dependent on their thermal constraints, it is important to find ways to analyze and simultaneously optimize their electromagnetic (EM) and thermal performances. This paper presents an approach for coupling the finite element EM and thermal analyses of electrical machines using temperaturedependent material properties so that temperatures inside a candidate machine can be predicted simultaneously with its electromagnetic performance. In addition to steady-state conditions, the coupled analysis has been extended in this paper to transient operation for machines that are required to deliver high torque/power for short intervals. Three 30 kW 10-pole 12-slot surface PM machines optimized for maximum torque density, minimum cost, and maximum efficiency, respectively, have been investigated. This coupled EM-thermal analysis makes it easier for designers to maximize the winding current density to achieve the highest possible torque/power ratings within thermal limits set by the winding insulation or demagnetization limits. W. Jiang, T.M. Jahns
2013-033 033 Evolving and Emerging Applications of Power Electronics in Systems IEEE Journal of Emerging and Selected Topics in Power Electronics, Vol. 1, No. 2, June 2013 Adjustable speed drives, data centers, energy conversion, flexible ac transmission system (FACTS), GaN, HVDC, integrated magnetics, power electronics, power supplies, semiconductor devices, SiC. The continuing trend toward greater electric cation and control of functions in consumer, commercial, industrial, transportation, and even medical applications promises a dynamic and increasingly important role for power electronics.The growing penetration of power electronics in energy systems is driven by new materials such as SiC and GaN, as well as new packaging technologies which allow the physical integration of electronics with powered and controlled devices such as motors. Advances in very high-frequency conversion led by the application of SiC and GaN devices promises to make converteron-a-chip technology possible, but concurrent advances in passive component technology are necessary.The principal challenge to application penetration remains cost reduction. J.G. Kassakian, T.M.Jahns
2013-034 034 Reducing Switching Losses in BLDC Motor Drives by Reducing Body Diode Conduction of MOSFETs IEEE Energy Conversion Congress and Expo, Denver, CO, Sept.15-19, 2013. This paper focuses on switching losses in hard switched converters. More specifically, on reverse conduction losses of MOSFET intrinsic body diodes as employed in BLDC motor drive inverter circuits. Synchronous rectification (SR) has been extensively implemented in low-voltage switch-mode dc/dc power conversion to reduce diode conduction losses. Extending the benefits of SR to high-voltage applications requires careful attention to the reverse conduction behavior of the synchronous rectifier MOSFET’s intrinsic body diode. The proposed technique for reducing body diode conduction is to add a MOSFET back-to-back, in series with the rectifying switch, and a Schottky or SiC type diode around the series switch combination. This research builds on previous patented work in which the proposed technique is used in low voltage dc-dc converter applications. This new work focuses on higher voltage motor drive applications. C. Brown, B. Sarlioglu
2013-035 035 Application Engineering of Wide Bandgap Semiconductors 224th Electrochemical Society Meeting, San Francisco, CA, Oct.27-Nov.1, 2013. This paper will address the importance and benefits of wide bandgap (WBG) semiconductors and provide example research results on utilization of these new devices in power electronic circuits. The paper will elaborate on device and circuit level opportunities, challenges, and potential solutions for various power electronic applications using WBG semiconductors. The paper will also present the current power electronic curriculum and education for undergraduate, graduate, and outreach education. Furthermore, suggestions are included on changes that can be made to include and promote WBG devices in power engineering education to develop a new workforce. B. Sarlioglu, D. Han, J. Noppakunkajorn, A. Ogale
2013-036 036 V2G Integration and Experimental Demonstration on a Lab-scale Microgrid Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. Electric and plug-in hybrid-electric vehicles are soon likely to be integrated as bidirectional energy storage elements with the electric grid or local microgrids. This paper discusses the interfacing of a plug-in vehicle with a lab-scale microgrid, and how this integration was successfully achieved with a power electronics converter that utilizes a powerfollowing droop controller. Simulations, which are verified with experimental results obtained with two electric research vehicles and a lab-scale microgrid, demonstrate that for both single and three-phase cases the imbalances created by vehicle charging and discharging meet, or nearly meet the required power quality and phase imbalance standards. The powerfollowing droop control is validated as an effective way of supporting the microgrid during transients as well as maintaining, in the long term, a desired charging rate. Fast charging is also briefly introduced as part of the future work. P.A. Mendoza-Araya, P.J. Kollmeyer, D.C. Ludois
2013-037 037 Reduction of Permanent Magnets in Small-Scale Wind Turbines Proc. of IEEE Energy Conversion Congress and Exposition (ECCE 2013), Sept. 15-19, 2013, Denver, CO. Small scale wind turbines offer an attractive method for electrification of remote locations using a renewable source of energy. The popular permanent magnet axial flux alternator design for small turbines published by Scoraig Wind Electric has been widely constructed using readily available materials, but requires a relatively large amount of costly rare earth magnets. The prohibitive magnet cost is a result of an ironless stator, which serves to eliminate cogging torque but ultimately introduces a large air gap in the magnetic circuit. This paper investigates the use of powered iron and other ferrous materials to fill the centers of concentrated windings in an attempt to balance magnet utilization and acceptable cogging torque. Simple techniques in line with the accessible manufacturing approach for these turbines are proposed. Experimental results using either a ferrous filing based soft magnetic composite or a steel slug configuration embedded in the stator windings are demonstrated. A 50% magnet reduction is achievable while maintaining or enhancing electrical performance with an acceptable increase in cogging torque. A. Shea, D. C. Ludois
2014-001 001 Simplified Terminal Behavioral Model for a Modular Multilevel Converter IEEE Transactions on Power Electronics Vol.29 No.4, April 2014 Circulating currents, control, modular multilevel converter, terminal model Modular multilevel converters (MMCs) are emerging to be an attractive approach for high-power applications. Equivalent circuitmodels and dynamicmodels for theMMCthat provide a faithful representation of system behavior are quite complex given the large number of energy states and control variables. They are not particularly useful in studying the terminal behavior of the converter and for the development of an intuitive control approach to regulate power transfer. This paper reduces the complexity of the MMC analytical model to an equivalent boost–buck converter circuit while providing particularly insightful transparency of the converter’s physical operation from a terminal perspective. The transformed boost–buck converter model and control performance are verified using simulations and experiments using a laboratory scale prototype. D.C. Ludois, G.Venkataramanan
2014-002 002 Analysis of High-Speed PCB with SiC Devices by Investigating Turn-off Overvoltage and Interconnection Inductance Influence Proc. of IEEE Applied Power Electronics Conference and Exposition (APEC), Forth Worth, TX, March 16-20, 2014. The purpose of this paper is to analyze the impact of interconnection inductances to overvoltage during turn-off transient of silicon carbide (SiC) devices. To understand the switching behavior of the SiC devices, the ringing and overshoots of the voltage caused by the device capacitance and interconnection inductances are considered. Parametric studies are conducted to compare the influences of printed circuit board (PCB) and packaging inductances on the peak turn-off overvoltage under various operating conditions. A prototype half-bridge buck converter with SiC MOSFETs is constructed for the experiments. Experimental results are shown to validate the simulation results. J.Noppakunkajorn, D.Han, B.Sarlioglu
2014-003 003 Efficiency Characterization and Thermal Study of GaN Based 1 kW Inverter Proc. of IEEE Applied Power Electronics Conference and Exposition (APEC), Forth Worth, TX, March 16-20, 2014. Rapid advancement of gallium nitride (GaN) based device technologies enables the possibility to design inverters that have superior performance capabilities compared to Sibased inverters. It is prevalently acknowledged that GaN-based switching devices outperform the Si-based counterparts in many aspects such as lower power consumption, and faster switching frequencies. GaN devices will benefit many applications such as hybrid and plug-in electric vehicles, solar power inverters, industrial motor drives, and aerospace. Nevertheless, the superiorities of GaN devices in inverter design have not been fully explored by researchers, and the purpose of this paper is to evaluate the high-efficiency capabilities of inverters that can be achieved using these new devices and the resulting benefits on the thermal aspect. As a case study, 1 kW GaN FETs inverter is considered. Loss and efficiency analysis is performed under various load conditions, and the requirements on heat sink for various ambient temperatures are specified according to the loss values obtained. Analysis results are compared with conventional Si-based inverters. D.Han, A.Ogale, S.Li, Y.Li, B.Sarlioglu
2014-004 004 CERTS Microgrid Demonstration with Large-Scale Energy Storage and Renewable Generation Special Issue: Energy Storage Applications for the Smart Grid. Distributed Generation, Distributed Resource, Islanding, Microgrid, Smart Grid, Renewable Energy, Advanced Energy Storage. The Consortium for Electric Reliability Technology Solutions (CERTS) Microgrid concept captures the emerging potential of Distributed Energy Resource (DER) using an automatous plug-and-play approach. CERTS views generation and associated loads as a subsystem or a “Microgrid.” The sources can operate in parallel to the grid or can operate in island, providing high levels of electrical reliability. The system can disconnect from the utility during large events (i.e., faults, voltage collapses), but also may disconnect intentionally when the quality of power from the grid falls below certain standards. CERTS Microgrid concepts have been demonstrated at the Alameda County Santa Rita Jail in California. The existing system included a 1-MW fuel cell, 1.2 MW of solar photovoltaic, and two 1.2-MW diesel generators. Adding a 2-MW, 4-MWh storage system, a fast static switch, and a power factor correcting capacitor bank enabled microgrid operation. The islanding and resynchronization methods met all Institute of Electrical and Electronics Engineers Standard 1547 and the reliability requirements of the jail. E. Alegria, T. Brown, E. Minear, R. H. Lasseter
2014-005 005 Real-world Performance of a CERTS Microgrid in Manhattan IEEE Transactions on Sustainable Energy. Distributed Generation, Distributed Resource,Islanding, Microgrid, CHP, Low Emissions, CERTS CERTS microgrid technology enabled the Brevoort, a 1950’s era luxury co-op tower in Greenwich Village,NY, to maintain power, water and heat during the week of wide spread utility outages left in the wake of Hurricane Sandy in late 2012. The microgrid system, anchored by four 100kW hybrid CHP units, powered the entire building including the central boilers, domestic water pumps, elevators and all apartments while most buildings in the lower third of Manhattan were without power, heat, and, in many cases, water. The Brevoort co-op board elected to convert the 20–story building from oil heat to the natural gas CHP system as part of an energy-efficiency green initiative that was fully implemented in 2010. In New York City, these hybrid cogeneration systems can operate in parallel with Con Edison utilities during periods of regularly available power. During a power grid failure, the units, with its permanent magnet generator and inverter with built in CERTS microgrid technology, will continue to power the residences. R. Panora, J. Gehret, M. M. Furse, R. H. Lasseter
2014-006 006 Voltage Source Control of PV Inverter in a CERTS Microgrid Transactions on Power Delivery Jan. 2014. Photovoltaic (PV), CERTS, microgrid, controller, intentional islanding. Microgrids are highly compatible with photovoltaic (PV) sources because of their ability to internally aggregate and balance multiple renewable sources. Traditional grid-connected PV inverter control configurations are basically current sourced and cannot easily control ac voltage or frequency. PV inverter using CERTS concepts can control ac voltage and frequency but has a major problem with load transients. During a load transient the PV microsource becomes overloaded with the possibility of collapsing the dc bus voltage resulting in ac voltage drop. This paper presents a PV inverter control strategy which enables PV to behave as a voltage source and be capable of maintaining dc bus voltage stability during load transient. With this PV inverter control configuration it is shown that the PV microsource can operate as a voltage source in the CERTS microgrid. W. Du, Q. Jiang, M. J. Erickson, R. H. Lasseter
2014-007 007 Comparative Study on Novel Dual Stator Radial Flux and Axial Flux Permanent Magnet Motors with Ferrite Magnets for Traction Application 2014 INTERMAG Conference in Dresden Germany, May 4-8. Axial flux permanent magnet motor (AFPMM), dual stator, finite element method (FEM), ferrite permanent magnet motors, hybrid electric vehicles (HEVs), radial flux permanent magnet motor (RFPMM), traction motors, torque density. High performance synchronous motors with less or no rare earth magnets for hybrid electric vehicles (HEVs) have attracted much attention due to the high cost and limited supply of the rare earth materials. Accordingly, this paper proposes two novel traction motors with ferrite magnets for HEVs, which have competitive torque density and efficiency as well as operation range with respect to a referenced rare earth magnet motor employed in the third-generation Toyota Prius, a commercialized HEV. The two proposed traction motors named as dual stator radial flux permanent magnet motor (DSRFPMM) and dual stator axial flux permanent magnet motor (DSAFPMM) adopt the same design concept which incorporate the unaligned arrangement of two stators together with the use of spoke-type magnet array and phasegroup concentrated-coil winding for the purpose of increasing torque density and reducing torque ripple. Finite element method (FEM) is utilized for predicting the main characteristics such as back EMF, cogging torque, electromagnetic torque, iron loss and efficiency in both motors. Moreover, a comparative study between the proposed DSRFPMM and DSRFPMM is performed under the same rated power condition. As a result, it is demonstrated that both the proposed ferrite permanent magnet motors could be good alternatives for traction application replacing the rare earth magnet motors. W. Zhao, T. A. Lipo, B. Kwon
2014-008 008 Material-Efficient Permanent Magnet Shape for Torque Pulsation Minimization in SPM Motors for Automotive Applications 2014 INTERMAG Conference in Dresden Germany, May 4-8. Electrical machines, electromagnetic force, finite element method (FEM), finite element analysis (FEA), permanent magnet (PM) machines, sinusoidal electromotive force (EMF). This paper focuses on the design and analysis of a novel material-efficient permanent magnet (PM) shape for surface-mounted PM (SPM) motors used in automotive actuators. Most of such applications require smooth torque with minimum pulsation for an accurate position control. The proposed PM shape is designed to be sinusoidal and symmetrical in the axial direction for minimizing the amount of rare earth magnets as well as providing balanced axial electromagnetic force, which turns out to obtain better sinusoidal electromotive force (EMF), less cogging torque and consequently smooth electromagnetic torque. The contribution of the novel PM shape to motor characteristics is firstly estimated by 3-D finite element method (FEM), and all the simulation results are compared with those of SPM motors with two conventional arched PM shapes, one previously reported sinusoidal PM shape and one step skewed PM shape. Finally, some finite element analysis (FEA) results are confirmed by experimental results. W. Zhao, T. A. Lipo, B. Kwon
2014-009 009 Optimal Design of a Novel V-type IPM Motor with Assisted Barriers for the Improvement of Torque Characteristics 2014 INTERMAG Conference in Dresden Germany, May 4-8. Finite element method (FEM), frozen permeability method (FPM), genetic algorithm (GA), magnetic torque, optimal design, torque, torque ripple, V-type interior permanent magnet motors (VIPMMs). This paper performs a study on the optimal design of V-type interior permanent magnet motors (VIPMMs) in which the rotor is equipped with assisted barriers for the improvement of average torque and torque ripple. The approach differs from conventional IPM motors in which the reluctance torque due to saliency reaches a maximum value at a rotor angle located 45 electrical degrees with respect to the maximum value obtained from the magnetic PM torque produced by the rotor magnets. Adoption of assisted barriers is employed to improve the torque production by making rotor asymmetric making the reluctance torque and the magnetic torque reach a maximum near or at the same current phase angle. In order to evaluate the contribution, the frozen permeability method (FPM) is utilized to segregate the torque into its reluctance and magnetic torque components. Firstly, an iterative optimization is performed on a concept design of a 6/4 VIPMM for demonstrating the design principle. Then the VIPMM is further optimized by algorithms such as Kriging method and genetic algorithm (GA) for improving the torque characteristics and efficiency. The optimal motor with assisted barriers shows substantially improved performance compared to a conventional design. W. Zhao, T.A. Lipo, B. Kwon
2014-010 010 A Novel Dual-Stator Axial-Flux Spoke-Type Permanent Magnet Vernier Machine for Direct Drive Applications 2014 INTERMAG Conference in Dresden Germany, May 4-8. Direct drive, double stator, finite element method (FEM), power factor, vernier machines. This paper proposes a novel topology as a double-stator axial-flux spoke-type permanent magnet vernier machine (PMVM), which has a high torque density feature as well as a high power factor at low speed for direct-drive systems. The operation principle and basic design procedure of the proposed machine are presented and discussed. Three-dimensional finite element method (3D FEM) is utilized to analysis its magnetic field and transient output performance. Furthermore, the analytical method and a simplified twodimensional finite element method (2D FEM) are also developed for the machine basic design and performance evaluation, which can effectively reduce the modeling and simulation time of the 3D FEM to achieve adequate accuracy. F. Zhao, T.A. Lipo, B. Kwon
2014-011 011 Aerodynamic Fluid Bearings for Translational and Rotating Capacitors In Non-Contact Capacitive Power Transfer Systems Industry Applications, IEEE Transactions on, Vol.50, No.2, pp.1025,1033, March-April, 2014. Wireless power transfer (WPT) is commonly accomplished with magnetic (inductive) techniques for a wide range of applications. Electrostatic or capacitive power transfer (CPT) approaches to WPT have had limited exposure primarily due to lower achievable power density when compared to inductive WPT techniques. Recently, high frequency (kHz-MHz) power electronics have reintroduced capacitive techniques as an option for WPT over short distances (<2mm) for applications such as slip ring replacement. To further the practicality of CPT, capacitive coupling must be maximized in an effective manner, i.e. the volumetric capacitance density of rotating/translational capacitors must be increased significantly. This paper proposes the use of aerodynamic fluid bearings to maximize capacitive coupling between stationary and moving surfaces by minimizing their separation distance allowing for greater surface area per unit volume. The technique allows microns of separation distance between moving surfaces while maintaining manufacturability and mechanical robustness. Coupling capacitance is increased up to 100 times greater than rigid plate rotating and translational CPT systems. Additional benefits include the estimation of mechanical system parameters such as speed. Operational characteristics and design highlights are presented and corroborated with experimental results for general slip ring replacement applications. D.C. Ludois, M.J. Erickson, J.K. Reed
2014-012 012 Quasi-Parallel Switched-Capacitor and Regulating PWM DC-DC Converter 2014 IEEE Applied Power Electronics Conference and Exposition(APEC), Forth Worth, TX, March 16-20, 2014. Datacenter power consumption makes up two percent of United States electricity consumption or 80TWhr. Roughly half of this energy is spent on cooling or lost in power conversion. Further as datacenters try to maximize compaction, the need for small and highly efficient power supplies is highlighted. Telecom power supplies often rely on large and lossy transformers to achieve large conversion ratios or to provide isolation for Quasi-Parallel or Sigma configurations. Low power switched capacitors converters can eliminate the large magnetic components and even provide ground isolation. Switched capacitor converters suffer from poor load regulation, poor line regulation, and discontinuous conversion ratios. Using a multilevel modular switched capacitor converter in a quasiparallel structure, a lesser power rated regulating converter can provide load regulation and line regulation. This configuration can provide lightweight, efficient, and magnetic-less power. K.Yeates, Y.Han
2014-013 013 Portable Electrification using Biogas Systems Humanitarian Technology: Science, Systems and Global Impact 2014,Boston, MA, May 13-15,2014. Electrification; developing countries; anaerobic digestion; biogas There is a strong correlation between electrification and rise in human development, but in developing countries access to electricity is often unreliable, unavailable, or unobtainable, especially from a centralized electric grid. Portable electrification using batteries provides an affordable energy source while sidestepping costs and regulations associated with physical transmission lines. In this paper, an anaerobic digestion system consumes organic waste and produces biogas that fuels an electric generator for battery charging. The paper presents a detailed approach for conducting an engineering economic analysis of the system. Two candidate business models to evaluate the potential of portable energy storage device distribution services of different sizes to return profit are proposed. The results offer a promising starting point for local entrepreneurs to implement similar business models, particularly at a small scale with a modest capital investment of about $1500, with revenue of about $100 per week, and a payback period of 18 months on the investment. C.A.Cherry, M.Riosa, A.McCordb, S.Stefanosb, G.Venkataramanana
2014-014 014 High Frequency Resonant Bidirectional SEPIC Converter Suitable for Battery Equalization and Charger Applications 2014 IEEE Applied Power Electronics Conference and Exposition(APEC), Forth Worth, TX, March 16-20, 2014. This paper proposes a DC-DC converter that can be used in battery equalization and charging and discharging applications. The proposed topology is a high frequency (? 5 MHz) resonant bidirectional SEPIC DC-DC converter. The resonant technology and high frequency operation will allow the size and cost of a battery equalizer to be reduced because of the ability to reduce the size of the magnetic components. The topology of the DC-DC converter is proposed, analyzed, and realized, and then verified by simulation and experimental results. It is shown that this converter can obtain an efficiency that is greater than 81%. T.Florencki, Y.Han
2014-015 015 Power Electronics Integration on Battery Cells 2014 IEEE Applied Power Electronics Conference and Exposition(APEC), Forth Worth, TX, March 16-20, 2014. This paper introduces a distributed battery equalization structure for battery strings in which power electronic converters are integrated on battery cells. Because each cell is managed individually, the proposed structure has many advantages over traditional ones. Design issues about power converters are discussed. A two-level control algorithm is proposed to perform global and local functions including battery monitor, protection, sensing, and control. At last, the authors built a prototype, which successfully validated the proposed concept. Y.Li, Y.Han
2014-016 016 A Flexible and Cost Effective Gate Drive Platform for Rapid Prototyping 2014 IEEE Applied Power Electronics Conference and Exposition(APEC), Forth Worth, TX, March 16-20, 2014. There is a current movement within the scientific,engineering, educational and entrepreneurial communities called “making.” Most electronics makers are familiar with hardware offerings ArduinoTM and XbeeTM, which are user friendly rapid prototyping platforms for microcontrollers and wireless networks respectively; however an equivalent solution for power electronics is not available at comparable cost. This paper presents a well designed, low cost, flexible gate driver capable of interfacing with a variety of IGBT and MOSFET discrete or module packages over a wide operating space. The gate driver provides more than 2kV of isolation with an isolation capacitance of less than 5pF while supporting gate drive powers of up to 5W with bipolar 15V rails in ambient temperatures up to 40C. Measurements of the prototype gate driver verify performance and other design metrics while keeping the cost significantly below commercially available offerings. A.Shea, D.C.Ludois
2014-017 017 Novel Field Weakening Technique for Surface Mounted Permanent Magnet Machine using Current Regulated Voltage Source Inverters Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), Ischia, Italy, June 18-20, 2014. windng switching; Current Regulated Voltage Source Inverter; Field Weakening; Internal Power Factor Field weakening control is a key technique for high speed operation of electrical machines. A novel Current Regulated Voltage Source Inverter (CRVSI) operation strategy is adopted in this paper to achieve high speed operation from Surface Mounted Permanent Magnet Synchronous Motor (SMPMSM). This strategy avoids any kind of previously proposed winding switching and achieves same benefits of high flux weakening. Machine operation is divided into two modes: two 3-phase CRVSI operation and three single phase CRVSI operation. During first mode of operation machine can be operated at maximum torque conditions as well as d-axes current control is applied for first stage of flux weakening. In second mode of operation, when machine reaches its constant power operation limit, CRVSIs operation is modified. Three 1-phase CRVSI are established such that machine operation reverts to achieve unity internal power factor at the elevated speed. Suitability of suggested current flow paths for the proposed topology is supported by inductance variation calculations. Furthermore effect of slot per pole per phase configuration on this flux weakling topology is discussed. Initial experimental results are provided to validate the simulation results. S.Atiq, T.A.Lipo, B.Kwon
2014-018 018 A Novel Topology for a Voltage Source Inverter with Reduced Transistor Count and Utilizing Naturally Commutated Thyristors with Simple Commutation Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), Ischia, Italy, June 18-20, 2014. Novel Topology, Inverter, VSI, Transistor, Thyristor. This paper discloses a novel topology for a voltage source inverter with certain advantages over conventional topologies. In particular, the circuit uses only three high performance transistor switches rather than six switches as in the conventional three leg inverter circuit. Thus, this circuit could prove to be attractive in applications requiring high cost switching components such as new silicon carbide and gallium nitride based devices. In addition to the three switches, two low cost thyristors are used per phase to provide commutation from positive to negative current. Theoretical analysis and simulation results are provided to verify its performance and feasibility. S.H. Rafin, T.A. Lipo, B. Kwon
2014-019 019 Investigating the Influence of Interconnection Parasitic Inductance on the Performance of SiC Based DC-DC Converters in Hybrid Vehicles Proc. of IEEE Transportation Electrification Conference and Expo (ITEC), Metro Detroit, Michigan, June 15-18, 2014. silicon carbide power devices; parasitic inductance; semiconductor loss; efficiency; DC-DC converters; hybrid electric vehicles Silicon carbide (SiC) based devices are known to outperform Si devices in many aspects, such as lower power dissipation, higher operating temperatures, and higher switching frequencies. SiC devices will benefit hybrid vehicles when applied into the DC-DC converters and inverters as part of the electrical power conversion needed to drive the powertrain. Nevertheless, SiC devices can suffer from oscillations as a result of the underdamped response to an RLC circuit composed of device output capacitance, parasitic inductance, and on-state resistance. This paper aims at investigating the influence of the interconnection parasitic inductance on the performance of SiC-based DC-DC converter in hybrid vehicles. D.Han, W.Lee, J.Noppakunkajorn, B.Sarlioglu
2014-020 020 Investigation of Dual-Inverter-Fed Drives for Permanent Magnet Synchronous Motor with Winding Switching IEEE IECON Conf., Dallas TX, Oct 28-Nov. 1, 2014. PM motors; field weakeing; high speed operation; winding switching A new method for Flux Weakening (FW) of Surface Permanent Magnet (SPM) motor is proposed. This method is termed a dual inverter-fed drive system with winding switching and can significantly extend the field weakening speed range of SPM. As a particular design example, the proposed method can increase the maximum output of a SPM motor by 73% without changing the battery ratingS, and can extend the constant power speed up to about 4 times the base speed without using demagnetizing current. The stator winding arrangement which allows the motor operate in various speed operations is discusses in this paper. The simulation and analysis of the drive system with respect to a SPM motor is implemented, and the simulation results show the motor operates reliably and flexibly by the proposed method. B.Tian, Z.Zhang, T.A.Lipo
2014-021 021 Loss Optimization and Ultracapacitor Pack Sizing for Vehicles with Battery/Ultracapacitor Hybrid Energy Storage Proc. of IEEE Transportation Electrification Conference and Expo (ITEC), Metro Detroit, Michigan, June 15-18, 2014. Battery and ultracapacitor hybrid energy storage systems have long been proposed as alternatives to battery-only systems for electrified vehicles. Prior research has focused on system topologies, dc/dc converter design, control methods, and evaluating specific applications. This work utilizes a rule-based control method and dynamic programming combined with a vehicle model to evaluate the reduction in energy storage losses that can be achieved for various drive cycles and ultracapacitor pack sizes. Dynamic programming is used to determine the optimum power split between the battery and ultracapacitor pack for a specified drive cycle and calculates the best performance a causal control algorithm could achieve. The analysis shows that dynamic programming can significantly improve the loss reductions compared to the basic rule-based control, making it possible to reduce the size of the ultracapacitor pack needed to deliver meaningful energy savings. Experimental tests have been carried out on battery and ultracapacitor cells that raise confidence in the accuracy of the model predictions for drive cycle metrics. P.J. Kollmeyer, L.W. Juang, T.M. Jahns
2014-022 022 Improved Modeling of Lithium-Based Batteries using Temperature-Dependent Resistance and Overpotential Proc. of IEEE Transportation Electrification Conference and Expo (ITEC), Metro Detroit, Michigan, June 15-18, 2014. State-of-Charge (SOC), battery management system (BMS), electric vehicle (EV), lithium iron phosphate battery, Kalman filter, Hybrid Power Pulse Characterization The temperature-dependent behavior of the resistance and overpotential of a lithium-iron-phosphate (LiFePO4) battery cell is explored in this paper. Offline experimental results from hybrid pulse power characterization (HPPC) tests and electrochemical impedance spectroscopy (EIS) methods for resistance and overpotential are explained using Arrhenius equations. Using a nonlinear regression technique, simulated drive cycle data are used to confirm the experimental findings and construct a generic cell model that explicitly takes temperature effects on the resistance and overpotential into account. The significance of the work lies in its confirmation of the inadequacy of the baseline linear-circuit model for lithium batteries at low temperatures and its presentation of a modeling approach that provides much better agreement with measured battery characteristics. L.W. Juang, P.J. Kollmeyer, T.M. Jahns, R.D. Lorenz
2014-023 023 Variable Characteristic Permanent Magnet Motor for Automobile Application SAE International, April 8-10, 2014, Detroit. This paper describes a variable magnetomotive force interior permanent magnet (IPM) machine for use as a traction motor on automobiles in order to reduce total energy consumption during duty cycles and cut costs by using Dy-free magnets. First, the principle of a variable magnetomotive force fluxintensifying IPM (VFI-IPM) machine is explained. A theoretical operating point analysis of the magnets using a simplified model with nonlinear B-H characteristics is presented and the results are confirmed by nonlinear finite element analysis. Four types of magnet layouts were investigated for the magnetic circuit design. It was found that a radial magnetization direction with a single magnet is suitable for the VFI-IPM machine. Magnetization controllability was investigated with respect to the magnet thickness, width and coercive force for the prototype design. The estimated variable motor speed and torque characteristics are presented. Following the explanation of the design process, the experimental results obtained for the prototype machine are described. The torque characteristic and the transient torque behavior during magnetization state (MS) control were confirmed experimentally. Based on the experimental results, the total loss in a typical duty cycle was calculated. Since too frequent manipulation of the magnetization state results in larger loss due to the loss caused by the MS control current, hysteresis control was implemented to reduce the number of MS changes. Using the proposed control algorithm, the total energy consumption was calculated in comparison with that of a conventional motor. It was found that the VFI-IPM motor reduces the total energy consumption significantly T.Kato, T.Fukushige, K.Akatsu, R.Lorenz
2014-024 024 Position Self-Sensing Evaluation of Novel CW-IPMSMs with a HF Injection Method IEEE Trans. on Industry Applications Self-sensing, sensorless control, interior permanent magnet synchronous machines (IPMSMs), high frequency injection, multi-saliencies, finite element methods. The paper introduces two different novel designs of interior permanent magnet synchronous machines with concentrated windings (CW-IPMSMs) which are attractive to a self-sensing control system. The new machines have some advantages: lower sub-harmonics of air-gap flux density & magnetomotive force (MMF) and lower machine losses including eddy current losses. The machines have been adapted for self-sensing applications by using a high frequency (HF) injection method. The main machine parameters affecting the estimation accuracy are analyzed such as: fundamental frequency saliencies, cross saturation, HF inductance, HF resistance and harmonic distortion due to multi-saliencies. The experimental results verify that the novel machines can reach very high performance with good selfsensing properties regarding the accuracy of the estimated position/speed of electric drives even without the multisaliencies decoupling compensation method. X.Wang, W.Xie, G.Dajaku, R.M.Kennel, D.Gerling, R.D.Lorenz
2014-025 025 Influence of Pole and Slot Combinations on Magnetic Forces and Vibration in Low-Speed PM Wind Generators IEEE Trans. on Magnetics Electromagnetic forces, finite element method (FEM), generators, permanent magnet (PM) machines, vibration. In this paper, radial forces and torque ripple characteristics are investigated in permanent magnet (PM) machines having different pole and slot combinations. Using the PM machines with concentrated windings could be beneficial in direct-drive wind generators since it is possible to reduce the size and weight of the generator. The PM machines with concentrated windings having a large number of poles are compared to investigate the effect of pole and slot combinations on force and vibration characteristics in lowspeed generators. Cogging torque waveforms and torque ripple are investigated using time-stepping finite-element analysis. Analysis of radial forces is presented, including investigation on radial force density distribution, total forces on teeth, and time-dependent force waveforms on a tooth. Structural analysis and experimental modal analysis are performed on the prototype generator. The main mode of vibration in the prototype machine is observed experimentally and the results are in good agreement with the simulations. M.Valavi, A.Nysveen, R.Nilssen, R.D.Lorenz, T.Rolvag
2014-026 026 Investigation of Key Factors Influencing the Response of Permanent Magnet Synchronous Machines to Three-Phase Symmetrical Short-Circuit Faults Proc. of IEEE Transportation Electrification Conference and Expo (ITEC), Metro Detroit, Michigan, June 15-18, 2014. This paper investigates the three-phase symmetrical short-circuit characteristics of a permanent magnet synchronous machine (PMSM). Closed-form solutions are derived to predict both the steady-state and transient response of a PMSM to three-phase symmetrical short-circuit (SSC) faults. The developed expressions account for the impact of pre-fault operating conditions and include provisions for incorporating magnetic saturation effects. The influence of machine parameters is studied to identify the key parameters that have a major influence on the steady-state and peak transient values of the fault currents. It is shown that increased inductance saliency ratio, reduced stator resistance, and higher magnetic saturation all increase the peak transient value of the demagnetizing d-axis current. Finite-element (FE) analysis is used to build confidence in the fault current predictions of the developed analytical model. G.Choi, T.M.Jahns
2014-027 027 Optimal Design of a Novel Asymmetrical Rotor Structure to Obtain Torque and Efficiency Improvement in Surface Inset PM Motors Conference on the Computation of Electromagnetic Fields, Annecy, France, May, 25-28,2014. Asymmetrical rotor, finite element method, frozen permeability method, genetic algorithm, magnetic torque, optimal design, reluctance torque, surface inset PM motor, surface-mounted PM motor. This paper proposes an optimal design of a novel asymmetrical rotor structure for surface inset PM motors to obtain torque and efficiency improvement. Different from the conventional approach, the proposed design of asymmetrical rotor structures is employed to improve the torque production by creating rotor asymmetry to allow the reluctance torque and the magnetic torque reach a maximum at the same current phase angle. In order to evaluate the contribution, the frozen permeability method (FPM) is utilized to segregate the torque into its reluctance and magnetic torque components. For demonstrating the design concept and obtaining a criterion for improving torque by making full use of torque components, an optimal design by iterative computation is first to be performed utilizing finite element method (FEM). Based on the obtained criterion, the optimal design by algorithms such as Kriging method and genetic algorithm is applied to further improve the torque and efficiency. As a result, the performance of the proposed surface inset PM motor by 2-step optimization is dramatically improved compared with that of the conventional surface inset PM motor. Furthermore, a comparison between the optimized surface inset PM motor and a conventional surface-mounted PM (SPM) motor is also performed under the same operating condition, which demonstrates that the optimized surface inset PM motor can significantly save the magnet amount compared to the conventional SPM motor for producing the same output torque. W. Zhao, T.A. Lipo, B. Kwon
2014-028 028 Optimal Design of Ultra-High Speed Axial Flux Permanent Magnet Motor with Sinusoidal Back-EMF The Korean Institute of Electrical