电网电压跌落下DFIG电磁暂态过程及转子侧控制策略研究

On the Electromagnetic Transient Process and Rotor-side Control Strategies of DFIG under Power Grid Voltage Sags

以双馈风力发电机(DFIG)作为对象,对转子侧变换器的定子磁链定向矢量控制是基于假设电网电压稳定。而矢量控制下对电网电压波动时控制性能较差。对DFIG在电网电压跌落时的电磁暂态过程进行分析,仿真得出定子电流的波形与频谱分析,在控制策略中引入定子等效励磁电流,从而引入两个补偿量,重新构建控制框图并进行对比仿真分析显示,加入了补偿量的控制策略与矢量控制方法相比,转子侧的故障电流得到了抑制,提高了DFIG在电网电压跌落时的运行能力。

For the rotor-side converter of the doubly-fed induction generator（ DFIG）,its vector control strategy for the stator flux orientation is usually based on the steady power grid voltage assumption. While this control strategy is not suitable considering the power grid voltage sag condition. Thus,the electromagnetic transient process of DFIG under power grid voltage sag condition is analyzed. Based on the simulated waveform and spectrum of the stator current,the equivalent stator excitation current is introduced into the control strategy. Two compensation quantities are added. The comparative simulation analysis results show that the improved control strategy can restrain the rotor fault current,and increase the operation ability of DFIG under grid voltage sags.