Optimal design of cooling channel structure for surface-mounted permanent magnet synchronous motors based on genetic algorithm

Aiming at the problem of high pressure drop in the flow channel of a certain type of surface-mounted permanent magnet synchronous motor cooling system, an optimization design method for the flow channel structural parameters based on a genetic algorithm is proposed. The novelty of this study lies in its comprehensive consideration of the effects of five geometric parameters on the pressure drop: the width W, height H, and length L of the flow channel, and the inner and outer radii r and R of the bend in the channel. With pressure drop reduction as the dominant objective, simultaneous improvements in flow velocity uniformity and the thermal state of the motor are achieved. Through computational fluid dynamics simulations and the control variable method, the effects of the flow channel structural parameters on the pressure drop are obtained. It is found that the channel width W and height H are the main influencing parameters, while the channel length L and the inner and outer bend radii r and R are secondary influencing parameters. Taking W, H, L, r, and R as design variables and a flow channel pressure drop of 20 kPa as the optimization objective, a genetic algorithm is adopted for intelligent optimization of the flow channel structural parameters. The results of this optimization show that for values W = 16 mm, H = 8 mm, L = 151 mm, r = 2.5 mm, and R = 15 mm, the flow channel pressure drop is 20.1 kPa, representing a reduction of 27.96% compared with that before optimization. The flow velocity uniformity index is increased from 2.857 to 3.067 after optimization, an improvement of 6.9%. Compared with their values before optimization, the maximum temperatures of the motor stator and winding are decreased by 5.9% and 5.8%, respectively.