The Coordinated Control Strategy of Doubly-fed Induction Generators With an Energy Storage Dynamic Voltage Restorer for Low Voltage Ride Through

In the process of grid connection of wind power, in order to ensure the failure of the grid to recover the fault recovery bus voltage as soon as possible, the wind turbine must have a certain voltage ride through capability. Aiming at this problem, a strategy of realizing low voltage ride through (LVRT) by using super capacitor based dynamic voltage restorer (SCDVR) energy storage and doubly-fed induction generators (DFIG) is proposed. When the grid voltage fails, the active power that each of the dynamic voltage restorer (DVR) and the DFIG needs to absorb is distributed through a proportional coordination control strategy. Making full use of the compensation ability of DVR and wind turbine rotor rotational kinetic energy to ensure the grid voltage stability is constant and the wind turbines can be sustained parallel operation. The validity of the coordinated control strategy is verified by the simulation results. Numerical example results show that the coordinated control strategy can reduce the capacity and power of the dynamic voltage restorer, which is of great significance in engineering application.