多物理域耦合求解的轮毂电机温度场

为研究温度变化对电动汽车用轮毂电机的工作性能和使用寿命的影响，采用场路耦合法将轮毂电机有限元模型与外电路联合求解，建立了包含轮毂电机本体、外部驱动控制电路的联合仿真模型，充分考虑了外部激励中时间谐波电流对磁场的影响. 然后，将计算得到的绕组铜耗、定子铁芯损耗、永磁体涡流损耗以及杂散损耗等作为热源，采用磁热耦合法将其耦合到各部件进行瞬态温度场研究，综合考虑了电机工作过程中其损耗分布在时间和空间位置上的瞬态变化特性，热源损耗与温度场实时精确耦合. 详细研究了负载运行时轮毂电机各部件温度随时间的变化情况，以及温度的空间分布特性. 多物理域耦合法实现了电磁场与外电路的直接耦合，电磁场与温度场的顺序耦合. 最后，对轮毂电机进行台架试验. 研究结果表明:仿真计算结果与试验结果在额定工况下温度的最大误差为4.96%，峰值工况下最大误差为10.55%. 

Temperature Field of in-Wheel Motor Using Coupled Multi-physics Domain Solution

In order to study the influence of temperature change on the working performance and service life of in-wheel motor for electric vehicles, a coupled multi-physics analysis method is proposed. Firstly, the field-circuit coupling method is used to solve the finite element model of the in-wheel motor and the external circuit. A joint simulation model including the in-wheel motor and external drive control circuit is established, which takes into account the influence of the time harmonic current from external excitation on the magnetic field. Then, the calculated winding copper loss, stator core loss, permanent magnet (PM) eddy current loss and stray loss are used as heat sources, and they are coupled to each component by magneto-thermal coupling method to study the transient temperature field. The transient variation characteristics of the loss distribution in time and space are overall considered, and the thermal loss and temperature field are coupled accurately in real time. The temperature variation of each component over time and space is studied in detail. The direct coupling between electromagnetic field and external circuit, and the sequential coupling between electromagnetic field and temperature field are realized by the coupled multi-physics analysis method. Finally, the bench test of the in-wheel motor is carried out. The results show that the maximum temperature error between the simulation and tests is 4.96% under rated conditions, and the maximum error is 10.55% under peak conditions.