Evaluation of voltage sag ride-through of a doubly fed induction generator wind turbine with series grid side converter

With steadily increasing wind turbine penetration, regulatory standards for grid interconnection have evolved to require that wind generation systems ride-through disturbances such as faults and support the grid during such events. Conventional ride-through accommodations result in high currents and torque or are unable to ride-through down to zero volts. This paper explores two DFIG configurations in which a series grid side converter (SGSC) is employed exclusively for voltage sag ride-through. A control strategy applicable to both configurations is developed whereby the SGSC engages to stabilize the stator flux at the beginning and resolution of the sag event. Simulation results show excellent zero voltage ride-through response.