Design and Experimental Study of Water Cooling System for External Rotor Permanent Magnet Synchronous Motor

In response to the harsh working conditions of high-power external rotor permanent magnet synchronous motors, a water-cooling structure is utilized to balance the heat generated by an external rotor permanent magnet synchronous motor, ensuring effective heat dissipation. In this study a two-dimensional electromagnetic simulation model was established to obtain a cloud diagram illustrating the temperature field distribution of a permanent magnet motor using the magnetic-thermal coupling method. Three cooling water channel models were designed: the axial Z-type, rectangular water channel opening circumferential spiral type, and circular water channel opening circumferential spiral type. Additionally, the temperature field distribution of the motor windings during stable operation is obtained using the electromagnetic field-fluid field-temperature field coupling method. By comparing different cooling schemes, the optimal cooling system was selected, which showed a 32.57% decrease in the winding temperature after the implementation of the water-cooling system. The water-cooling system designed in this study has some theoretical and practical value in the study of heat dissipation systems for external rotor permanent magnet synchronous motors.