Rotor short circuit protection technology
This is the method of some wind power manufacturers use more, it is equipped with a crowbar circuit in the rotor side of the generator, provides a bypass for the rotor side circuit, detected in power system fault voltage sag, doubly fed induction generator excitation converter locking, and input bypass circuits (energy release resistance) to protection device. Limit the overvoltage by excitation converter current and rotor winding function. In order to maintain the generator operation (when the doubly fed induction generator according to induction motor operation).
At present, there are several typical crowbar circuits as follows: