Method for controlling low-voltage ride through of doubly-fed type wind generating set

The invention relates to a method for controlling low-voltage ride through of a doubly-fed type wind generating set. The method comprises the following steps that: (1) a frequency converter system sends detected low-voltage ride through signals to a master control system of a fan control system; (2) the master control system sends low-voltage ride through triggering signals to an action module, a fault-shielding module and a state monitoring module respectively; (3) the action module performs limit speed adjustment on a doubly-fed type wind generator, and the master control system sends control signals to a propeller-variable system; (4) the fault-shielding module shields faults of voltage signals measured by partial frequency converters, and state signals and speed variation rate of partial propeller-variable systems; (5) the state monitoring module monitors the propeller-variable speed of the propeller-variable system, the rotation speed of the doubly-fed type wind generator, the voltage signals of the frequency converters and the state of the frequency converters; and (6) a judging module judges whether the fan control system enters the low-voltage ride through recovering stage or not, and the wind generating set stops working if faults exist after entering the low-voltage ride through recovering stage; on the contrary, the system continues being combined to the grid. The method can be widely used in wind power industries.