摘要
电压不稳定是弱电网特征之一,风力发电机并网后常常受到弱电网电压扰动的影响,甚至造成风机脱网使电网震荡加剧。通过分析在电网电压扰动的情况下的变速恒频(VSCF)双馈感应(DFIG)风力发电机组运行特点,建立风力发电机组详细模型,将一种改进的基于发电机定子磁链定向的矢量控制策略移植到风力发电机不间断运行的控制中,对风力发电机组转子侧PWM输出电流和直流母线电压进行控制,从而达到风机稳定运行目的。在电网需要时,向电网快速提供无功功率,调节电网电压和稳定弱电网。后利用Matlab/Simulink软件进行仿真研究,仿真结果表明该系统在电网波动时能够较好的抑制电网电压对转子电流和直流母线电压的影响。
The wind turbines is often influenced by voltage disturbance because of voltage instability under the weakpower grids. This paper proposes a method for a variable speed constant frequency （VSCF）wind turbine withdoubly-fed induction generator （ DFIG ）to stay connected to the grid during voltage disturbance. The keypoint of the method is to limit the inrush current in the rotor and the voltage in the DC bus in order to protect the wind turbines and the weak power grids. Then a detailed DFIG model is built and a control strategy is propsoed. In order to regulate network voltage,stabilize weak network,the DFIG using the proposed method can supply reactive power fast,hold system supply stabJlity,reduce risk of voltage collapse and network splitting. Finally,the performance of the new control through severe voltage disturbance conditions is demonstrated by simulation.
