基于灭磁理论的双馈风机高电压穿越策略

High Voltage Ride Through Strategy of Doubly-fed Induction Generator Based on De-excitation Theory

针对双馈异步风力发电机(doubly-fed induction generator,DFIG)转子侧变流器的传统灭磁控制策略存在精确观测定子磁链和加大变流器输出端电压的问题,基于经典的定子磁场定向、功率解耦控制系统进行研究,提出了一种改进高电压穿越控制策略。首先,利用定子电流暂态分量获取转子灭磁电流指令值和转子侧变流器输出端电压补偿项,避免对定子磁链的精确测量。然后,将灭磁控制与前馈电压控制相结合,加快定子暂态磁链衰减,抑制转子过电流。最后,仿真结果验证了所提策略可以有效拓宽DFIG故障穿越范围,提升其穿越性能。

The conventional de-excitation control strategy of the rotor side converter of doubly-fed induction generator(DFIG)has the problems of accurately observing the stator flux and increasing the output voltage of the converter.To solve these problems,based on the classical stator magnetic field orientation and power decoupling control system,an improved high voltage ride through control strategy is proposed.Firstly,the transient component of stator current is used to obtain the rotor de-excitation current command value and the output voltage compensation term of the rotor side converter,so as to avoid the precise measurement of the stator flux.Then,the de-excitation control is combined with feedforward voltage control to speed up the stator transient flux attenuation and restrain the rotor overcurrent.Finally,the simulation results verify that the proposed strategy can effectively broaden the fault ride through range of DFIG and improve its ride through performance.