| 摘要 |
A control method for low voltage ride through comprises the following steps: 1)A control circuit (9) monitors a DC bus voltage of a set of frequency converters (3, 4) connected between a wind generator rotor and a power grid (12) and a voltage of the power grid; 2) If the monitored DC bus voltage of the set of frequency converters is judged to be higher than a designed value, the control circuit controls a thyristor (7) in a crowbar protection circuit connected to the wind generator rotor to be closed to obtain a shunt protection; 3) After the thyristor is closed, the control circuit controls a stator breaker (1) which is connected between a wind generator stator and the power grid to disconnect the wind generator stator and the power grid; 4) After the stator breaker disconnects the power grid and the wind generator stator, the control circuit further controls a breaker (5) of a shunt circuit to be opened firstly and then be closed, the thyristor is turned off automatically, and thus the protection function of the shunt circuit is recovered; 5) This state is maintained until the control circuit monitors a recovery of the voltage of the power grid, a generator synchronous control breaker is closed rapidly, and a normal operation is recovered. The control method provides low voltage ride through performance with a simple control strategy. |
