Performance analysis and research on LVRT of PMSG wind power systems with SDBR

This paper proposes a low-voltage ride-through (LVRT) protection scheme without fault current limiter (FCL) on the grid-side inverter (GSI), based on energy balance characteristics of permanent magnet synchronous generator (PMSG) wind power systems during the grid voltage drop. The scheme utilizes a series dynamic braking resistor (SDBR) to consume the excess active power from the PMSG transmitting to the grid during the voltage drop. A detailed design procedure and control strategy for the SDBR is presented. The theoretical analysis and the PSCAD/EMTDC simulation results prove that the proposed protection scheme can boost GSI voltage, limit GSI over-current, stabilize DC-link voltage, guarantee the safe and stable operation of the converters, and then improve LVRT capability of PMSG wind power system.