为了优化电网电压发生不对称故障时双馈风力发电机(doubly fed induction generator,DFIG)的低电压穿越(low voltage ride through,LVRT)能力,提出一种优化方法,即在转子侧串联电阻和电容改善DFIG的LVRT能力。传统的Crowbar方法中,故障期间DFIG将产生不可控的情形并且吸收一定无功,不利于电网电压恢复。而采用转子串阻容方法,限制了转子侧电压的负序分量和直流分量,抑制了转子开路电压和转子过电流,保证了DFIG在故障期间可控状态,并提供无功,有利于电网电压的恢复。仿真结果表明,所提方法能使DFIG成功进行低电压穿越,保证了DFIG在故障期间可控。
英文摘要:
In order to optimize the low voltage ride through (LVRT) capability of doubly fed induction generator (DFIG) in the event of an asymmetrical fault in the grid voltage, an optimization method is proposed in which the series resistor and capacitance Improve DFIG LVRT ability. In the traditional Crowbar method, DFIG will produce uncontrollable conditions during the fault and absorb a certain reactive power, which is not conducive to grid voltage recovery. The rotor series resistor method is used to limit the negative sequence component and the DC component of the rotor side voltage, and the rotor open circuit voltage and the rotor overcurrent are suppressed, which ensures the controllable state of the DFIG during the fault and provides the reactive power, which is beneficial to the grid voltage recovery. The simulation results show that the proposed method can make DFIG successfully carry out low voltage crossing, which ensures that DFIG is controllable during fault.