Stator Harmonic Currents Suppression for DFIG Based on Feed-Forward Regulator Under Distorted Grid Voltage

This paper presents a stator harmonic currents suppression method for doubly fed induction generators (DFIGs) under distorted grid voltage. In the proposed control strategy, the feed-forward regulator instead of the resonant regulator is employed to eliminate the negative impacts on the stator current caused by the distorted grid voltage. The leading phase compensator is applied to compensate the system delay when the sampling frequency is low. This approach can provide both the good dynamic response and strong rejection ability against the stator harmonic voltages. Based on the stator current model of DFIG, the feed-forward regulator is designed in detail. The comparison between the resonant controllers and the feed-forward regulator is also made on the basis of Bode diagram. Then, the robustness against the frequency variations and the parameter deviations is analyzed. Finally, the simulation and experimental results are presented to validate the effectiveness of the proposed control strategy.