To study the temperature distribution and change the law of the permanent magnet synchronous motors used in vehicles during extreme driving, the concept of extreme variable working condition (a running process from a low-power condition where a motor can run for a long time, to peak power and then to a low-power condition) was proposed. To calculate the temperature field, an overall simplified model of a motor was established, and the three-dimensional temperature field of the motor under some single working conditions was obtained by finite element simulation. Then, the accuracy of the simulation model and the calculation results were verified by a comparison with bench test data. Finally, a temperature field simulation calculation of the motor was carried under extreme variable working conditions, and the temperature rise characteristics of the motor under extreme working variable conditions were obtained. The results were obviously different from those of the normal working conditions.

为了研究极端行驶期间车辆中使用的永磁同步电动机的温度分布并改变其规律，提出了极端可变工作状态的概念（从低功率状态运行到电动机可以长时间运行到峰值功率，然后达到低功率条件）。为了计算温度场，建立了电动机的整体简化模型，并通过有限元模拟获得了在某些单一工作条件下电动机的三维温度场。然后，通过与基准测试数据进行比较，验证了仿真模型和计算结果的准确性。最后，在极端可变的工作条件下进行了电动机的温度场模拟计算，获得了极端工作变量条件下电动机的温升特性。结果明显不同于正常工作条件。