Control strategies of doubly fed induction generator-based wind turbine system with new rotor current protection topology.

A protection scheme of a doubly fed induction generator (DFIG) based wind turbine system during faults is crowbar activation. With this protection, the rotor side converter (RSC) is temporarily disconnected, and its vector control over the stator active and reactive power is lost, leading to poor power quality at the point of common coupling (PCC). This paper presents a new protection scheme for transient rotor current to improve the performance of DFIG during grid disturbance. The new scheme, consisting of a crowbar and series circuit, is connected between the rotor windings and RSC to enhance the low voltage ride-through capability of DFIG. The proposed scheme successfully limits the transient rotor current and dc-link voltage, and a disconnection of RSC from the rotor windings is avoided during fault. Additionally, RSC and grid-side converter controllers are modified to improve the voltage at PCC. Simulations on matlab/Simulink verify the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]