Low Voltage Ride Through Technology Applied to Permanent Magnet Direct-driving Wind Generator Units

With the installed capacity rising of wind turbine generators,wind power system operation in the case of power failure has become particularly important.Some grid-connection standards require the wind turbine to ensure no off-grid operation within a certain range when the grid voltage drops.Aiming at back-to-back direct-drive wind power system,net side control strategy of double PWM controller was analyzed.And unloading DC resistive crowbar circuit hardware circuit and control strategy were designed.The results showed that DC resistance unloading is simple,reliable and has greatly enhanced the fan's low-voltage ride through capability.