Thermal calculation of high speed permanent magnet synchronous motor based on equivalent thermal network and CFD method

Aiming at accuracy of temperature field calculation of high-speed permanent magnet synchronous motor, the equivalent thermal network method and fluid structure coupling numerical method were used to calculate the thermal performance of a water-cooled amorphous alloy stator motor. The fluid structure coupling model of the motor was established, and the effects of uneven air temperature distribution in the motor on density, specific heat capacity, dynamic viscosity and thermal conductivity were considered. Based on the principle of least square method, the expression of air physical properties changing with temperature was obtained. The variable temperature physical properties were applied to the air in the motor, and compared with the temperature field calculation results of the constant temperature physical properties of the air in the motor and the air friction loss calculation results of the outer surface of the rotor. The results show that after the variable temperature physical property is applied to the air inside the machine, the area of the high temperature area of the rotor increases, the calculated value of the temperature rise is closer to the reality, and the air friction loss on the outer surface of the rotor decreases by 4.0%. Finally, the temperature rise experiment platform of the prototype was built to verify accuracy of the calculation results of the equivalent thermal network and fluid solid coupling method. © 2022 Editorial Department of Electric Machines and Control. All rights reserved.