SMES Based Reconfigured Converter Architecture for DFIG to Enhance FRT and Grid Forming Capability

Grid forming control (GFM) based wind farms can support the safe and stable operation of power systems dominated by renewable energy. However, GFM based Doubly Fed Induction Generators (DFIGs) have difficulties in riding through serious voltage faults. And their grid forming ability is restricted by the power reserve and capacity of the converter. This paper proposes a reconfigured converter architecture for DFIG with SMES integrated into its DC bus. During normal operation, DFIG adopts the GFM strategy for primary frequency regulation. If the frequency modulation capacity of DFIG is inadequate, SMES outputs active power through an energy storage side converter (ESC) to keep the frequency within the specified safety range. When voltage faults occur, SMES outputs dynamic reactive current to support voltage recovery through ESC. The simulation results show that the proposed architecture and strategy can effectively enhance the GFM and voltage ride-through capability of DFIG.