Sliding mode controller based on feedback linearization for damping of sub-synchronous control interaction in DFIG-based wind power plants

This paper presents a robust nonlinear controller based on feedback linearization technique and sliding mode control to alleviate sub-synchronous control interaction (SSCI) in doubly-fed induction generator (DFIG)-based wind farms connected to series-compensated transmission lines. To take full advantage of DFIG converter control, the feedback-linearized sliding mode controller (FLSMC) is designed for rotor side converter (RSC) and grid side converter (GSC) through scrutinizing system linearizability, performing feedback linearization, and designing sliding mode control based on the feedback-linearized system. Eigenvalue analysis and electromagnetic transient (EMT) simulation are carried out to assess the performance of the FLSMC at varied operating conditions, and the capability of the FLSMC in alleviating SSCI is compared to the sub-synchronous resonance damping controller (SSRDC) and proportional-integral (PI) controller. Besides the effectiveness in mitigating SSCI, the FLSMC also improves the robustness of the studied system under external disturbances and parameter uncertainties.