Study on low voltage ride through characteristic of full power converter direct-drive wind power system

With an increasing amount of wind energy installed, the behavior of wind power system during grid disturbances becomes more important, grid operators require that wind turbines stay connected to the grid during voltage dips. A control method can be used to keep direct-drive wind power system with back-to-back converters using permanent magnet generator connected to the grid during voltage sags. When the voltage sags happen, the grid-side converter of direct-drive wind power system operating at STATCOM mode, the reactive current is determined by the depth of voltage sag, then the reactive power can be rapidly provided to support the grid and help direct-drive wind power system low-voltage ride-through. All this was verified by simulation and experiment. This is illustrated that for direct-drive wind power system, the capability of low voltage ride through can be effectively improved by operating at STATCOM mode during grid voltage sags.