Torque improvement of wound field synchronous motor for electric vehicle by PM-assist

Abstract

In order to improve the performance of the wound field synchronous motor (WFSM), the permanent magnet assist (PM-assist) is investigated in this paper. The effect of the permanent magnet assist is dependent on the inserted position of the permanent magnets. Thus, four models whose permanent magnets are inserted at each different positions are suggested. Then, the most effective position of the permanent magnet is decided by the mean torque per employed amount of the permanent magnet. By inserting the permanent magnets into the decided position of a WFSM designed for a small electric vehicle traction, the PM-assisted WFSM is designed. By comparing the torque and the efficiency of the original WFSM and the PM-assisted WFSM, the effectiveness of the PM-assist is figured out. Finally, the validity of this research is verified by the experiment using the manufactured WFSM.