Active Fault-tolerant Fractional-order Terminal Sliding Mode Control for DFIG-based Wind Turbines Subjected to Sensor Faults

The recent high penetration of wind energy conversion system (WECS) -based power generators being integrated into power grids demands advanced control techniques to ensure an efficient power production performance. This paper presents an active fault-tolerant nonlinear control strategy for the rotor side converter (RSC) control of doubly fed induction generator (DFIG) driven WECS subjected to model uncertainties and rotor current sensor faults. Two fractional-order nonsingular terminal sliding mode controllers are proposed for rotor current regulation and speed trajectory tracking. Furthermore, the control scheme is incorporated with a state observer to estimate the rotor current dynamics during sensors’ faults. Benefitting from the proposed sliding surfaces, fast finite-time convergence of system states is guaranteed, and the chattering is effectively suppressed. Closed-loop stability analysis is investigated in the sense of the Lyapunov stability criterion. Comparative performance assessments under faulty situations are conducted, and the proposed fault-tolerant control scheme’s promising speed and power tracking performance over fractional-order sliding mode control technique is revealed.