Analysis and Experimental Validation of Rotor Optimal Design on the Noise Reduction of Permanent Magnet Synchronous Motor for Electric Vehicle

Since permanent magnet synchronous motor (PMSM) is the key component of electric vehicle (EV) propulsion system, the noise, vibration and harshness (NVH) behavior of PMSMs is essential to the riding amenity of EVs. The noise performances of PMSMs are mainly caused by the electromagnetic forces and can be amplified by the mechanical structure. Therefore, in this paper, the electromagnetic forces are comprehensively studied in terms of time and spatial harmonic distributions with the employment of 2D finite element analysis (FEA) and Fourier transformation (FFT) under different operating conditions. Then, in order to improve the noise performance, an optimal design of the rotor is proposed to minimize the radial electromagnetic force. Finally, the effectiveness of the optimal rotor design is verified by both anechoic chamber test and real vehicle test.