三相对称故障下双馈风力发电机控制策略

随着风力发电系统的日益普及，双馈风力发电机作为一种最常用的风力发电机，问题已逐渐凸显。由于风能不可控因素多，稳定性差，给电网控制带来了诸多不确定因素。为研究双馈风力发电系统在电网发生三相对称故障时的故障保护技术，首先采用数学分析的方法对双馈风机进行建模，分析了三相对称故障下风机的运行状态；随后搭建了Crowbar保护电路，利用电压跌落发生器模拟电压跌落，在实验平台进行试验；最后进行仿真验证。通过实验及仿真可以看出Crowbar电路对转子侧电流的突增有明显的抑制作用，采取增加Crowbar电路的方法来实现三相对称故障下的低电压穿越是可行的。

Double-Fed Wind Generator Control Strategy in Three-Phase Symmetrical Fault

With the growing popularity of wind power generation system,double-fed wind generator （DFWG）as one of the most commonly used wind turbines,its problems are gradually revealed.Since wind energy has the characteristics of multiple uncontrollable factors and poor stability,it has brought many uncertainties for the grid control.To study the fault protection technology of double-fed wind power generation system in a three-phase symmetrical fault,firstly,this paper used the method of mathematical analysis to construct double-fed wind generator （DFWG）model,and analyzed the running state of the generator in three-phase symmetrical fault.Then Crowbar protection circuit was built;and voltage sag was simulated by a voltage sag generator in the experimental platform for testing.Finally,the verification was carried out through simulation.The experiment and simulation results show that the Crowbar circuit has significantly inhibition effect on current surge on the rotor side.So,the method of adding the Crowbar circuit to achieve low voltage ride through（LVRT ）in three-phase symmetrical fault is feasible.