Control Strategy Study of DFIG with LVRT

In recent years, the proportion of the wind power in the grid is increasing rapidly. When the grids faults results in voltage decline, the widespread tripping of wind generators could lead to transient instabilities and local or overall blackouts. So it is concerned that the wind turbines merge into the grid and the request of the low voltage ride through(LVRT)ability is proposed. This paper analysises the transient responses of DFIG during grid fault, and then the three LVRT methods of DFIG are presented, Excitation Control strategy is mainly discussed. The model and the strategy of Excitation Control are implemented in the power system simulation tool Matlab/Simulink. The control algorithm was implemented in the existing motor control unit without any additional hardware cost. The controller was successfully tested in a test. The effect is good.