Comprehensive Efficiency Modeling of Electric Traction Motor Drives for Hybrid Electric Vehicle Propulsion Applications

Extensive research done in the recent past has proven that power electronic converters and electric propulsion motors are extremely critical components for modern hybrid electric vehicle (HEV) propulsion applications. Therefore, it is essential that both the traction motor and the associated drive operate at their optimal efficiencies throughout the driving schedule. In typical HEV propulsion applications, the traction motor and the drive are used over the entire torque/speed operational range. In view of this fact, this paper aims at modeling the inverter and motor losses/efficiencies over typical city and highway driving schedules. The noteworthy losses within a typical three-phase dc/ac traction inverter, such as the switching and conduction losses for both the insulated-gate bipolar transistors and the antiparallel diodes, are modeled and simulated over the city and highway driving patterns. An induction motor (IM) is used for a medium-sized sport utility vehicle, which was modeled in the advanced vehicle simulator (ADVISOR) software. The significant IM losses that were considered in the study include the stator copper losses, rotor copper losses, and core losses. Thus, the average efficiencies of both the inverter drive and the induction traction motor are evaluated and summarized under city as well as highway driving conditions. Finally, based on the individual-model-based efficiency analysis, the overall traction motor drive system efficiency is estimated.