Research on Torque Pulsation Suppression of Permanent Magnet Synchronous Motor Based on Harmonic Injection

Permanent magnet synchronous motor (PMSM) is affected by the nonlinearities of the inverter during operation resulting in harmonics in the motor stator current, which causes the motor to pulsate in torque and cause additional losses. To address this problem, an adaptive harmonic injection algorithm is proposed to suppress the harmonic currents of the motor. First, the mathematical models of the 5th and 7th harmonics of the motor are established respectively. Secondly, the harmonic extraction module uses Kalman filter to extract harmonic currents, and the harmonic suppression module introduces Model Reference Adaptive Parameter Identification (MRAI), which, combined with multi-rotation PI control, constitutes an adaptive harmonic suppression algorithm that effectively avoids the effects of inductance, resistance, and magnetic chain changes on the suppression of harmonics during the motor dynamics. Finally, the effectiveness of the proposed algorithm to suppress torque pulsation is verified by comparing the simulation results before and after adding the algorithm.