Investigation on characteristics and optimal shapes of interior PM synchronous motor for electric vehicle application

The torque ripple of interior PM synchronous motor (IPMSM) operated in wide speed range through flux weakening variously varies according to operating point. That is mainly generated because of the difference of magnetic saturation in each point. Moreover, from the torque performance point of view, the IPMSM with concentrated winding is relatively disadvantage compared with that with distributed winding and surface PM synchronous motor. Therefore, in this paper, each optimal model minimizing torque ripple at the base and maximum speed and cogging torque is investigated by an optimization method. In addition, the characteristics of each model are compared by finite element analysis and characteristic equation. In the end, the final results show the optimal shape according to the operating point of IPMSM must be changed to satisfy torque performance.