An LVRT Control Strategy Based on Flux Linkage Tracking for DFIG-Based WECS

For doubly fed induction generator (DFIG)-based wind energy conversion systems (WECSs), large electromotive force will be induced in the rotor circuit during grid faults. Without proper protection scheme, the rotor side of DFIG will suffer from overcurrents, which may even destroy the rotor-side converter (RSC). To mitigate this problem, a new flux-linkage-tracking-based low-voltage ride-through (LVRT) control strategy is proposed to suppress the short-circuit rotor current. Under the proposed control strategy, the rotor flux linkage is controlled to track a reduced fraction of the changing stator flux linkage by switching the control algorithm of RSC during grid faults. To validate the proposed control strategy, a case study of a typical 1.5-MW DFIG-based WECS is carried out by simulation using the full-order model in SIMULINK/SimPowerSystems. In the case study, a comparison with a typical LVRT method based on RSC control is given, and the effect of the control parameter on the control performance is also investigated. Finally, the validity of the proposed method is further verified by means of laboratory experiments with a scaled-size DFIG system.