Analysis of Temperature Field and Water Cooling of Outer Rotor In-Wheel Motor for Electric Vehicle

In view of the narrow installation space of high power density and high torque in-wheel motor, the heat existed the in-wheel motor is balanced by cooling water channel to ensure the heat dissipation of the high power density in-wheel motor. In this paper, Ansoft Maxwell software is used to establish the two-dimensional loss simulation model of in-wheel motor, and the winding loss, stator core loss, rotor core loss and permanent magnet eddy current loss of in-wheel motor are calculated respectively. The temperature field calculation model of in-wheel motor is established. The heat exchange coefficient of motor is calculated, and the equivalent treatment of windings is carried out. The spiral channel is selected to cool the motor. The CFD software is used to simulate and analyze the cooling fluid in the channel. The heat dissipation coefficient curve is calculated. Finally, the calculated results of in-wheel motor loss and heat dissipation coefficient curve are imported into the transient temperature field for simulation, and the temperature field distributions before cooling and after cooling are obtained. The results show that the temperature drop of winding is 32%, the temperature drop of stator core is 30%, the temperature drop of permanent magnet is 26%, and the temperature drop of rotor is 25%. The spiral channel structure adopted in this paper is reasonable and feasible, which provides a certain theoretical reference value for the research and development of in-wheel motor heat dissipation system.