A novel control strategy of an active crowbar for DFIG-based wind turbine during grid faults

The crowbar resistance plays an important role in the protection of Doubly-fed induction generator (DFIG) wind power generation systems during grid voltage dips. This paper presents a novel control strategy primarily based on the real-time adjustable resistance crowbar structure. Design and control of the real-time adjustable resistance crowbar structure is described to limit the peak values of the rotor currents and DC-link voltage under a preset threshold. Further more, reactive power is provided both by grid side converter (GSC) and rotor side converter (RSC) in good time to assist the recovery of the grid voltage. The comparison of the response of single fixed crowbar resistance and real-time adjustable crowbar resistance is examined by simulation on a 1.5MW practical DFIG-based wind power generation system. The simulation results verify the correctness and effectiveness of the new control strategy.