Improved Full Control of Variable-Pitch Wind System Based on the DFIG using Third Order Sliding Mode Control in All Operating Zones

This paper suggests full control of a variable-pitch wind system (VPWS) based on a doubly fed induction generator (DFIG); by using the maximum power point tracking (MPPT) and pitch angle control strategies by employing a third order sliding mode controller (TOSMC) to ensure a better performance against stochastic wind variations. Knowing that the TOSMC constitutes an effective and promising solution regarding the minimization of the chattering caused by the first and second order sliding mode controllers on the one hand and on the other to ensure fast and good tracking. In this context, the MPPT strategy has been designed with the TOSMC to ensure maximum exploitation from the VPWS on the one hand, on the other hand, the pitch angle control strategy has been designed to limit the power extracted to its maximum value as well as to ensure the stability of the VPWS against high wind speeds. To test the robustness of the proposed controller, a comparative study between the other controllers was performed. Simulation results are validated using two different wind speed profiles (step and random change of wind speed) under Matlab/Simulink environment. The results obtained demonstrated the robustness of the proposed controller compared to other conventional controllers.