大型风力发电机在电网电压扰动下的特性

Characteristics of large scale wind turbine system under voltage disturbance from power grid

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.为了避免此种情况的发生,通过分析在电网电压扰动情况下的变速恒频(VSCF)双馈感应(DFIG)风力发电机组运行特点,建立了风力发电机组模型,将一种改进的基于发电机定子磁链的定向矢量控制策略移植到风力发电机不间断运行控制中,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的目的.利用Matlab/Simulink软件进行仿真,结果表明,该系统在电网波动时能够较好地抑制电网电压对转子电流和直流母线电压的影响.

The wind turbine is often influenced by the voltage disturbance from the voltage instability of the weak power grid. A method to keep the connection to the grid during the voltage disturbance for a variable speed constant frequency （VSCF） wind turbine with doubly-fed induction generator （DFIG） was proposed. The key point 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 turbine and weak power grid. A detailed DFIG model was built and the control strategy was proposed. The performance of the new control system under severe voltage disturbance conditions was demonstrated by simulation. The simulation results show that in the case of power grid fluctuation, the system can suppress the impact of the rotor current and DC bus voltage.