Sizing a switched reluctance motor for electric vehicles

This paper proposes a methodology to determine the peak and continuous power ratings of a switched reluctance motor (SRM) used for the electric propulsion of an Electric Vehicle (EV). The input data consist of the EV main specifications (e.g., rated and maximum velocities, vehicle mass, city and highway driving schedules, etc.). Estimation of the variations of copper and core losses with vehicle speed and motor output power is necessary to calculate the SRM continuous power rating. These loss variations are estimated by taking into account the operation principles of SRMs and assumed (or known) loss values at only one operating point. Using the obtained expressions, the SRM efficiency contours can be then estimated before the SRM is actually designed and built. This paper shows that the thermal duty of the SRM can be reduced by appropriate choice of the individual loss components in the design process