Robust Nonlinear Double Integral Sliding Mode Controller Design for Mitigating SSR in DFIG-Based Wind Farms

This paper proposes a nonlinear robust double integral sliding mode controller for mitigating the sub-synchronous resonance (SSR) while improving the steady-state error performance in a doubly-fed induction generator (DFIG)-based wind farm. The proposed controller is designed for the rotor-side-converter (RSC) as the RSC has a significant impact on mitigating the SSR as related to the grid-side-converter (GSC). Exterior disturbances are included in the RSC dynamical model to demonstrate the proposed controller’s robustness. The control law is obtained in a manner that it will satisfy the overall stability and it is proved using the Lyapunov stability theory. Finally, simulation studies are conducted on a DFIG-based wind farm which is developed in the MATLAB platform using the SIMPOWER Toolbox. The result compares with existing SMCs in terms of reducing capability the frequency of oscillations due to the SSR.