Harmonic Current Cancellation Method for PMSM Drive System using Resonant Controllers

In a permanent magnet synchronous motor (PMSM) drive system, many nonlinear effects in both the inverter and motor have a negative impact on the motor current and result in current distortion. In this paper, to reduce the current distortion, a resonant controller (RC) is used in parallel with a proportional and integral (PI) regulator in the current controller in the synchronous reference frame. To improve the stability of the RC, a modified transfer function is used. To avoid the interaction between the two types of controllers, a low-pass filter (LPF) is added to suppress the influence of a sudden change of reference. As a result, the harmonic components of the motor current can be reduced greatly, and the dynamic response can be kept the same as that of a PI regulator. Experimental results show that the proposed control method is effective.