双馈风力发电机三相短路电流分析

为了研究双馈风力发电机组的低电压穿越控制问题,分析了双馈风力发电机定子端三相短路时短路电流的产生机理,给出了双馈风力发电机在空载同步转速条件下的定转子短路电流的近似解析表达式.在此基础上,根据双馈风力发电机内部的电磁关系,分析了发电机故障前不同转速、输出有功功率及无功功率等运行状态对双馈发电机短路电流的影响.在理论分析的基础上,建立了3 MW双馈风力发电机的模型,对发电机定子端三相短路故障状态进行了仿真研究.仿真结果表明:通过定转子短路电流的近似解析表达式和发电机故障前的初始状态可以有效对双馈发电机短路电流进行定性分析,为进一步研究双馈风力发电机的低电压穿越能力提供了理论依据.

Analysis of three-phase short circuit current of doubly fed induction generator

In order to research the low voltage ride through(LVRT) control of doubly fed induction generator(DFIG),the principle of short circuit current of DFIG when three-phase short circuit fault occurred in stator is analyzed.The short circuit current approximate equations of DFIG in free load and synchronous speed condition were deduced.The influences caused by pre-fault state such as speed,active power and reactive power were analyzed based on the electromagnetic relationship of DFIG.A 3MW DFIG model was built,and the three-phase fault was simulated in stator side of the DFIG.The simulation results showed that the short circuit current of DFIG can be analyzed through the short circuit current approximate equations and generator pre-fault condition.It can be taken as theoretical base for the research on LVRT control of DFIG.