Research on Vibration and Noise Suppression of Permanent Magnet Motor via Variable Air-gap Based Multi-level Topology Optimization

With the increasing sales of new energy electric vehicles(EVs), the market has put forward higher demands on vehicle performance, and vibration noise has become a key index for the performance evaluation of automotive permanent magnet(PM) drive motors. In order to suppress the vibration-noise characteristics of permanent magnet drive motors under multi-variable operating conditions, a multi-level topology optimization design method based on variable air-gap domain is proposed. First, the characteristic electromagnetic forces that cause different vibration sources of the motor are derived, and the concept of variable air-gap domain hierarchical topology design is elaborated. Then, the variation characteristics of the characteristic electromagnetic force of the case motor under multiple operating conditions are analyzed. Then, the topology of the motor is divided into two parts: stator-rotor basic domain and air-gap design domain, and the electromagnetic performance of the motor is improved by optimizing the parameters of the stator-rotor basic domain, respectively, and then the characteristic electromagnetic force of the motor is weakened by the topology optimization method of air-gap domain, so as to suppress the vibration noise of the motor. Finally, the electromagnetic performance and vibration-noise characteristics of the motor are compared and analyzed by finite element simulation, which verifies the effectiveness of the proposed optimization design method. This study provides a new solution for the design of automotive drive motors with low vibration and noise under multiple operating conditions.