A Terminal Sliding Mode Approach for the Rotor Side Converter of a DFIG-Based Wind Energy System

This paper proposes a terminal sliding mode approach for the rotor side converter of a DFIG-based wind turbine. It aims at enabling the wind turbine to satisfactorily operate under unbalanced grid conditions such as voltage sags, while ensuring high performance dynamic responses in the presence of uncertainties and external disturbances. The controller was derived using a novel terminal sliding mode structure based on the tracking errors of the rotor currents. The controller parameters were auto-tuned using a fuzzy logic approach. The performance of the proposed approach was assessed using realistic settings including voltage sags of various depths and parameter variations. A comparison analysis with a standard SMC was also carried out.