Design of two-phase switched reluctance motor (SRM) for two-wheel electric vehicle and torque-density based comparison with three-phase SRM

Abstract

In this work, literature is presented for motor drives of two-wheel electric vehicle. There is a strict space constraint for accommodating the hub-motor in a two-wheel electric vehicle. Permanent magnet (PM) motors are widely used in these applications as they have high flux density and magnetic loading. Hence, they can meet high torque requirements at low speed. Switched reluctance motor is a PM free alternate for the application. However, torque-density is poor in the lowerspeed region. The two-phase switched reluctance motor offers an advantage over the three-phase motor in terms of torque density. A comparison of two-phase and three-phase SRM is presented to highlight the advantage of the two-phase motor for torque-density. A two-phase SRM is designed with higher torque density to meet the space constraints and typical torque-speed requirements of electric two-wheeler. A two-phase 8/4 motor is designed to demonstrate the advantages of a two-phase switched reluctance motor over the three-phase motor. Simulation results are presented for the designed motor compared to a commercial 3 kW brushless DC permanent magnet motor used in a two-wheel electric vehicle. Comparison is drawn in terms of torque-speed characteristics for a fixed battery voltage and current rating. The results show suitability of a two-phase switched reluctance motor candidate for the application.