Research on the Optimization of the Temperature Field of an Outer Rotor In-wheel Motor Based on Oil Cooling

In order to solve the heat dissipation problem of permanent magnet synchronous hub motor in pure electric vehicles during long-term operation, this study proposes a temperature field simulation and oil cooling structure optimization scheme. Based on MotorCAD, a 10 kW motor temperature field model is constructed, focusing on analyzing the influence mechanism of permanent magnet eddy current loss and rotor iron loss on temperature rise, and clarifying the internal temperature distribution law; combining Maxwell electromagnetic simulation to obtain heat source data, and determining the heat generation rate of components and key surface heat transfer coefficients through calculation models; designing a new oil cooling flow channel, and using Ansys to compare the temperature field before and after cooling. The results show that the maximum temperature rise of the optimized structure is reduced by 5%, and the heat dissipation efficiency is increased by 28% compared with the single water channel, providing an innovative solution for the design of hub motor cooling system.