Evaluation of soft switching for EV and HEV motor drives

Soft switching has the potential of reducing switch stresses and of lowering the switching losses as compared to hard switching. To understand the effectiveness of the soft-switching technique, when applied to electric vehicle (EV) and hybrid electric vehicle (HEV) systems, it may be necessary to first evaluate their system requirements and performance. This evaluation process would require knowledge of the vehicle dynamics. The vehicle load requires a special torque-speed profile from the drivetrain for minimum power ratings to meet the vehicle's operational constraints, such as initial acceleration and gradability. The selection of motor and its control for EV and HEV applications are dictated mainly by this special torque-speed requirement. As a consequence, this requirement will have a strong influence on the converter operation. This paper makes an attempt to evaluate EV and HEV running in both standard Federal Test Procedure 1975 city driving and highway driving cycles. A simplified analysis is carried out for several of the most commonly used electric motors operating on the optimal torque-speed profile. Special attention is given to the converter conduction and switching losses, by analyzing the switching losses, and by assuming that an ideal soft-switching scheme will have zero switching losses, one can evaluate the improvement in the system efficiency if a soft-switching control is used. The relative significance of soft switching for EV and HEV systems is then established.

[1]  G. Venkataramanan,et al.  Pulse width modulation with resonant DC link converters , 1990, Conference Record of the 1990 IEEE Industry Applications Society Annual Meeting.

[2]  Mehrdad Ehsani,et al.  Soft switched capacitively coupled DC-AC converter for high power , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.

[3]  Mehrdad Ehsani,et al.  Optimized instantaneous torque control of switched reluctance motor by neural network , 1997, IAS '97. Conference Record of the 1997 IEEE Industry Applications Conference Thirty-Second IAS Annual Meeting.

[4]  Jih-Sheng Lai.  Resonant snubber-based soft-switching inverters for electric propulsion drives , 1997, IEEE Trans. Ind. Electron..

[5]  Tore Undeland,et al.  Power Electronics: Converters, Applications and Design , 1989 .

[6]  Mehrdad Ehsani,et al.  High-speed torque control of brushless permanent magnet motors , 1988 .

[7]  Timothy J. E. Miller.  Converter Volt-Ampere Requirements of the Switched Reluctance Motor Drive , 1985, IEEE Transactions on Industry Applications.

[8]  M. Ehsani,et al.  Optimized torque control of switched reluctance motor at all operational regimes using neural network , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[9]  Mehrdad Ehsani,et al.  Parametric Design of the Drive Train of an Electrically Peaking Hybrid (ELPH) Vehicle , 1997 .

[10]  Thomas M. Jahns.  Torque Production in Permanent-Magnet Synchronous Motor Drives with Rectangular Current Excitation , 1984, IEEE Transactions on Industry Applications.

[11]  Hamid A. Toliyat,et al.  Propulsion system design of electric and hybrid vehicles , 1997, IEEE Trans. Ind. Electron..

[12]  Jih-Sheng Lai,et al.  Efficiency consideration of DC link soft-switching inverters for motor drive applications , 1994, Proceedings of 1994 Power Electronics Specialist Conference - PESC'94.

[13]  T.A. Lipo,et al.  High frequency series resonant DC link power conversion , 1988, Conference Record of the 1988 IEEE Industry Applications Society Annual Meeting.

[14]  Deepak Divan,et al.  The Resonant DC Link Converter--A New Concept in Static Power Conversion , 1986, 1986 Annual Meeting Industry Applications Society.

[15]  V. A. Sankaran,et al.  Power electronics in electric vehicles: challenges and opportunities , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.

[16]  Hamid A. Toliyat,et al.  ELECTRIC MACHINES IN ELECTRIC AND HYBRID VEHICLE APPLICATIONS , 1995 .

[17]  Mehrdad Ehsani,et al.  A review of soft-switched DC-AC converters , 1996, IAS '96. Conference Record of the 1996 IEEE Industry Applications Conference Thirty-First IAS Annual Meeting.

[18]  W. McMurray,et al.  Resonant snubbers with auxiliary switches , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[19]  Keith Wipke,et al.  ANALYSIS OF THE FUEL ECONOMY BENEFIT OF DRIVETRAIN HYBRIDIZATION , 1997 .