Improved FRT Control Scheme for DFIG Wind Turbine Connected to a Weak Grid

This paper presents an improved coordinated fault ride-through (FRT) control strategy for a doubly fed induction generator (DFIG) based wind turbine, (WT), in a weak grid. A technique for grid synchronization against voltage excursions, i.e., a Dual Second Order Generalized Integrator - Frequency Locked Loop (DSOGI-FLL) is utilized to extract a robust grid voltage synchronization signal irrespective of the mains condition to enhance the overall system performance. Besides, a decoupled double synchronous reference frame (DDSRF) dq current controller is devoted for the grid side converter, (GSC), controller to counteract current ripples and tackle the DC link voltage fluctuations. Also, a reactive power support scheme to manage the DFIG reactive power during contingencies and fulfill the grid codes obligations is presented. Moreover, additional control terms are employed with the DFIG converters controllers to counteract rotor as well as stator currents and regulate the rotor speed. Simulation results which assure the effectiveness of the proposed control scheme is presented.