Torque and current pulsation suppression method based on harmonic compensation for PMSM drive system under fluctuating DC-link voltage

For a single-phase rectifier, due to its operating characteristics, the DC-link voltage contains a second-order fluctuating component generated by fluctuating input power, which causes severe torque and current pulsations (TACP) in the motor. The hardware solution of adding an LC resonant filter is simple, but it does not meet the design goal of lightweight. An alternative solution to eliminate the TACP of the motor is using a suppression algorithm. However, it is difficult to obtain satisfactory suppression performance with conventional frequency compensation methods. To address this, a TACP suppression (TACPS) method based on harmonic compensation is proposed. Specifically, the specific harmonics are designed to inject into the stator voltage, thereby enabling to effectively suppress TACP while maintaining satisfactory performance. Moreover, with the assistance of the linear time-invariant (LTI) model, the stability and dynamic performance of the system with the proposed TACPS method are analyzed. Finally, extensive experimental tests are conducted to verify the effectiveness of the proposed TACPS method.