Rotor air-friction loss and thermal analysis of high-speed rotor for axial flux PM motor

This paper focuses on the air-friction loss and its effect on temperature of high-speed disc rotor for an axial flux PM motor with double rotors and sandwiched stator. The air-friction loss and the heat transfer coefficient on the rotor surface at different speed are obtained based on the formula method and Fluid-Solid coupling analysis. The rotor temperature distribution based on the coupling analysis of temperature and fluid field is obtained considering various losses and the impact of heat dissipation of air flowing in the motor cavity. Finally, the variation of rotor disc temperature with the rotating speed is presented for the high speed AFPM motor in this paper. The heat dissipation mechanism of rotor disc for the axial flux PM motor are revealed. Thus, it provides a significant guideline for the cooling structure design and the efficiency enhancement of high speed AFPM motor.