Sliding Mode Control of DFIG Wind Turbines with a Fast Exponential Reaching Law

This paper proposes a novel sliding mode control (SMC) technique for doubly fed induction generators (DFIGs) based on the fast exponential reaching law (FERL). The proposed FERL-based SMC is capable of reducing to a large extent the chattering phenomena existing in the sliding stage. Meanwhile, the reaching stage is accelerated with the introduction of an adaptive gain. The proposed method is employed in a DFIG-based wind energy conversion system (WECS) for direct power control (DPC). The FERL-based DPC approach is tested with simulations conducted in Matlab/Simulink under the scenarios of unbalanced grid voltage, grid fault conditions and highly unstable wind speed accompanied by an experimental study. The simulations and experimental results reveal the better performance of the proposed control method in active/reactive power tracking and dc-link voltage maintenance.