Sliding-Mode Control for a DFIG-based Wind Turbine under Unbalanced Voltage⋆

This paper reports a first-order sliding-mode control (1-SMC) design for controlling the doubly-fed induction generator (DFIG)-based wind turbine's rotor-side power converter. The design is particularly focused on keeping the generator successfully in operation under unbalanced grid voltage conditions, as today's grid codes require. Aside from controlling the stator-side active and reactive powers’ average value, the rotor-side converter is commanded so as to remove the fluctuations affecting the electromagnetic torque and the reactive power during unbalanced voltage. The paper aims to put forward the bases of the proposed design together with the described algorithm's stability proof. Finally, the appropriateness of the sliding-mode control to deal with the aforementioned disturbed scenarios is supported by means of simulation results.