Power control device and method used for low voltage ride through of direct-drive wind driven generator

The invention discloses a power control device and method used for low voltage ride through of a direct-drive permanent magnetic synchronous wind driven generator. The device comprises a generator speed measuring module, a direct current voltage measuring module, a generator terminal voltage measuring module, a generator terminal current measuring module, a grid measurement voltage measuring module, a grid measurement current measuring module, a maximum power tracking and controlling module, a grid measurement power measuring module, a wind speed measuring module, a pitch angle measuring module and a power coordination control module. The invention further provides the power control method, active power and reactive power of a unit in a temporarily stable state period can be coordinated and controlled, so that the direct-drive wind driven generator effectively achieves low voltage ride through in a maximum power tracking area and a power limiting area, and the unit can provide dynamic reactive support for a power grid in a low-voltage transient state period. The power control device and method can use the control means of the direct-drive wind driven generator self sufficiently and reasonably without adding unloading hardware, and the power control method is easy to implement and remarkable in effect.