Sub-synchronous Oscillation Mitigation of DFIG system Based on SVG Feedback Linearization

Abstract

To the doubly-fed induction generator(DFIG) system with static var generator(SVG), a feedback linearization control strategy for the SVG is proposed, and it is applied to the subsynchronous oscillation mitigation of the system. Firstly, combined with the principle of feedback linearization, the corresponding control method is designed for the SVG control link; Secondly, the eigenvalue analysis method is used to compare the influence of the control strategy on the stability of the system compared with the traditional control strategy when different parameters change under small disturbance; Finally, the phase diagram analysis method is used to analyze the mitigation effect of the control strategy on switching oscillation under different degrees of large disturbance. The results show that to the small/large disturbance caused by voltage sag, the SVG feedback linearization control strategy can better reduce the influence of voltage sag, and achieve better oscillation mitigation effect.