Due to the high power density characteristics of permanent magnet (PM) traction motors and the strict loading conditions of electric vehicle (EV) engine compartments, the excessive losses inside the motors can elevate rapidly the temperature rises, deteriorate the magnetic property of PMs, limit the output torques, and even cause the overheating damages of the machines. In order to guarantee the operational reliability, it’s of vital importance to research and develop the effective, reliable and economical cooling systems for improving the working performances of the PM traction motors. In this paper, the three-dimensional (3D) fluidic-thermal coupled model of a high power density interior PM traction motor is established based on the basic theory of computational fluid dynamics (CFD) and numerical heat transfer. The fluid flow and thermal distributions are analyzed based on finite volume method (FVM), and verified by experimental results. According to the heating characteristics of the motor, the external water frame structure of the motor shell is modified to improve the cooling efficiency. Taguchi method is used to optimize the cooling structural parameters, so as to reduce the steady-state temperature rise of the motor. The research work in this paper has certain reference significance for the design and development of high power density PM traction motors used in EV applications.

由于永磁（PM）牵引电机的高功率密度特性和电动汽车（EV）发动机舱的严格负载条件，电机内部的过度损耗会迅速升高温度升高，恶化永磁电机的磁性能，限制输出扭矩，甚至造成机器过热损坏。为了保证运行的可靠性，研究开发有效、可靠、经济的冷却系统对于提高永磁牵引电机的工作性能至关重要。在本文中，基于计算流体动力学（CFD）和数值传热的基本理论，建立了高功率密度内置永磁牵引电机的三维（3D）流热耦合模型。基于有限体积法（FVM）对流体流动和热分布进行了分析，并通过实验结果进行了验证。根据电机发热特性，对电机外壳外水架结构进行改造，提高冷却效率。采用田口法优化冷却结构参数，降低电机稳态温升。本文的研究工作对电动汽车应用的高功率密度永磁牵引电机的设计和开发具有一定的参考意义。采用田口法优化冷却结构参数，降低电机稳态温升。本文的研究工作对电动汽车应用的高功率密度永磁牵引电机的设计和开发具有一定的参考意义。采用田口法优化冷却结构参数，降低电机稳态温升。本文的研究工作对电动汽车应用的高功率密度永磁牵引电机的设计和开发具有一定的参考意义。