A coordinated control strategy of DFIG-based WECS for high voltage ride-through enhancement

This paper presents an analysis and operation of a Doubly Fed Induction Generator (DFIG)-based wind energy conversion system (WECS) under voltage swell condition. By taking into account both converters´ current ratings, a coordinated control scheme of the Grid Side Converter (GSC) and Rotor Side Converter (RSC), with dynamic reactive power supporting to the grid and rotor demagnetization current compensation based on the stator transient DC flux linkage component, is proposed. When the terminal voltage swells beyond 1.1pu, the WECS is controlled to output corresponding reactive current to realize stability control of the DC link voltage and alleviate system failure by optimizing the GSC and RSC´s current settings. Meanwhile, a rotor current compensation is applied to counteract the undesired flux linkage, which mitigates the output power and electromagnetic torque oscillations as well as the DC-link voltage fluctuations. The proposed strategy improves the reliability of the DFIG-based WECS during overvoltage, as have been validated by simulation.