Low Voltage Ride-Through of Directly Driven Wind Turbine with Permanent Magnet Synchronous Generator

A model of the directly driven wind turbine with permanent magnet synchronous generator (D-PMSG) was described in this paper. The D-PMSG was connected to a host AC power grid by a full scale power converter system which comprised two back-to-back PWM voltage source converters (VSCs) and a common DC-link. Active and reactive power of the two VSCs were controlled independently by employing PI current controllers with cross-coupling decoupling. In order to enhance its capability of low voltage ride-through (LVRT), the control strategy was proposed, the generator power was reduced according to the ratio of actual and rated grid voltage when the power characteristic of windmill was analyzed. Simulation results show that during voltage dip the proposed strategy can limit DC voltage and the rotational speed to their reference values, respectively, by adjusting the power of the generator and the pitch angle of the windmill, and supply reactive power for the grid.