Comparison of different motor design drives for hybrid electric vehicles

This paper describes an investigation into different motor designs for an application dictated by the performance of an existing hybrid electric vehicle drive (an internal permanent magnet motor). An induction motor and switched reluctance motor are studied. Torque over a wide speed range is required (base speed of 1500 rpm and maximum speed of 6000 rpm) and the total torque per volume is used as a key marker indicator. The efficiency is studied and efficiency plots are introduced; predicted losses are used to investigate thermal conditions and temperature rise, which affect the machines described in the paper. Results indicate that at 1500 rpm very high current density exists in all the machines whilst at 6000 rpm the iron loss dominates. The paper illustrates that the permanent magnet motor is not the sole solution to specifying a drive motor for this application.