High-Frequency Resonance Damping of DFIG-Based Wind Power System Under Weak Network

When operating in a micro or weak grid which has a relatively large network impedance, the doubly fed induction generator (DFIG)-based wind power generation system is prone to suffer high-frequency resonance due to the impedance interaction between the DFIG system and the parallel compensated network (series RL + shunt C). In order to improve the performance of the DFIG system as well as other units and loads connected to the weak grid, the high-frequency resonance needs to be effectively damped. In this paper, the proposed active damping control strategy is able to implement effective damping either in the rotor-side converter or in the grid-side converter, through the introduction of virtual positive capacitor or virtual negative inductor to reshape the DFIG system impedance and mitigate the high-frequency resonance. A detailed theoretical explanation on the virtual positive capacitor or virtual negative inductor has been given, and their parameters are also optimally designed. The proposed DFIG system damping control strategy has been validated by experimental results.