LVRT control strategy of CSC-DPMSG-WGS under unbalanced grid faults

A control strategy for direct-drive PMSG wind generation system based on three phase current source converter (CSC-DPMSG-WGS) is presented in this paper. By the proposed method, once unbalanced grid voltage fault happens, the generator-side converter limits the power which flows to DC-link rapidly, meanwhile the grid-side converter controls the positive and negative sequence currents respectively with a dc current closed loop to eliminate the power ripples of twice times fundamental frequency caused by unbalanced grid fault to maintain dc current stable. By coordinated control of generator-and grid-side converters, the stability of the CSC-DPMSG-WGS may be improved so that low voltage ride-through capability for CSC-DPMSG-WGS may be realized. Simulation results are provided to verify the proposed control strategy.