Abstract: The drive motor is one of the key components of the powertrain of new energy vehicles, and its performance index directly affects the quality of vehicle power output. With reference to the performance indicators of a new energy vehicle, permanent magnet synchronous motor is selected as the electric rear axle drive motor. The power, speed, torque and other key parameters of the motor are obtained through calculation. Based on the performance parameters of the motor, the motor structure parameters are selected. Based on MotorCad software, parametric method is used to reduce the peak of tooth groove torque as the optimization objective, the thickness, width and air gap length of the motor permanent magnet are optimized, and the efficiency MAP and external characteristic diagram of the motor are obtained. The results show that the cogging torque is significantly reduced compared with that before optimization. By selecting the driving China light-duty vehicle test cycle-passenger (CLTC-P) for simulation analysis, the rationality of the optimization design of permanent magnet synchronous motor is verified.

Key words: Electric rear axle; Permanent magnet synchronous motor; Structure design; Parameter optimization

摘要： 驱动电机是新能源汽车动力总成关键部件之一，其性能指标直接影响汽车动力输出品 质。参考某款新能源汽车整车性能指标，选用永磁同步电机作为电动后桥驱动电机，通过计 算获得电机的功率、转速及转矩等关键参数，基于电机的性能参数对电机结构参数进行选定， 基于 MotorCad 软件利用参数化方法以降低齿槽转矩峰值作为优化目标，对电机永磁体厚度、 宽度以及气隙长度进行优化设计，并得到电机的效率 MAP 图和外特性图，结果表明齿槽转矩 相比于优化前有较为显著的降低，选取中国乘用车行驶工况（CLTC-P）进行仿真分析，验证 了永磁同步电机优化设计的合理性。

关键词: 电动后桥；永磁同步电机；结构设计；参数优化