Development of Switched Reluctance Motor for EV Traction System 2001-01-0957

Switched Reluctance Motor (SRM) mainly has two advantageous characteristics such as no magnet and simple construction. These characteristics contribute lower cost and higher reliability compared with other motor systems such as brushless permanent magnet motors or induction motors. However, acoustic noise and output torque ripple should be improved when the SRM is applied to a traction system for passenger electric vehicle since these characteristics directly affect vehicle quietness and drivability.

In this paper, we describe a system configuration of the SRM traction system for passenger electric vehicle. The SRM traction system includes an electric motor, transmission gears and power inverter module. Then, an approach to improve acoustic noise and output torque ripple is introduced. Generation mechanisms of acoustic noise and output torque ripple are analyzed. It is found that reduction of magnetic attractive force between a motor stator and a rotor is very important factor to reduce acoustic noise and output torque ripple. We have developed a control algorithm to optimize the magnetic attractive force. This control algorithm is verified and evaluated through dynamometer and actual vehicle tests. As a result, we have successfully developed the SRM traction system which can be applicable for passenger electric vehicle.