Thermal Analysis and Cooling Structure Design of Axial Flux Permanent Magnet Synchronous Motor for Electrical Vehicle

The axial flux permanent magnet synchronous motor (AFPMSM) possesses various advantages, such as short axial length, compact structure, high power density and large torque density. At the same time, it will also bring high temperature rise to the motor. In this paper, four types of cooling structures are designed, and the best one is selected by comparing the cooling effect and cooling cost of the four given structures. Then, through optimizing the number of channels, the radial length and the axial length of cooling structure, the best parameters for a better cooling efficiency is rendered. To elevate the thermal analysis calculation efficiency of axial flux motors, a formula for calculating the best inlet velocity of cooling water is deduced, and the accuracy of the method is verified by the finite element simulation. According to the electromagnetic parameters and thermal physical parameters of AFPMSM, the 3D temperature field simulative model is established to analyze the temperature distribution of motor under rated operating conditions. Through the above analysis, a theoretical basis is provided for improving the thermal management of AFPMSM.