Resonance Damping of DFIG System Based on Multi-branch Virtual Impedance

This paper proposes a method to effectively suppress the resonance by reshaping the output impedance of doubly-fed induction generator(DFIG). Firstly, the impedance model of a typical DFIG system is established, and the mechanism of parallel resonance in DFIG system and its influencing factors are studied. Then, with the goal of effectively suppressing high-frequency resonance, this paper seeks the optimum values of the virtual resistances added to the stator branch and the grid-side converter(GSC) branch, uses the notch filter to implement the impedance reshaping of only harmonics, and optimizes the GSC and rotor-side converter(RSC) control strategies. Finally, using PSCAD, the effectiveness of this resonance suppression strategy is verified.