不对称故障下双馈风力发电系统网侧变流器的控制方法

Control Method of DFIG Grid-side Converter under Asymmetric Grid Voltage Drop

风力发电机组通过背靠背变流器与电网相连接,电压发生不对称故障时直流侧电压将发生大幅波动,而要消除这方面的影响,关键在于对网侧电流的控制。针对电网电压不对称故障下风电机组的表现,文章提出了一种适用于该情况下的网侧变流器的控制策略,以实现风电机组的低电压穿越。对发生不对称故障时网侧变流器的状态进行分析,得出其控制指令,使用Matlab/Simulink建立仿真模型,给出A相电压发生50%跌落下的仿真结果,验证了该控制策略的可行性。

DFIG is connected with the grid by Back-to-Back converter.The DC-side voltage will fluctuate widely under the asymmetric fault of grid voltage.Therefore,controlling the grid-side current is the key method to eliminate the influence.Aiming to the performance of DFIG under the asymmetric fault of grid voltage,a control method of grid-side converter is proposed for realizing low-voltage ride-through of wind turbines.The state is also analyzed,and then the control instruction is obtained.Furthermore,the simulation model by Matlab/Simulink is established,and the simulated results are given when A-phase voltage is dropping by 50%,which verifies the feasibility of the control strategy.