中文摘要：

在分析风电机组并网导则的基础上，首先对双馈异步风力发电机组进行数学模型的建立，分析了电网对称运行情况下的控制策略。然后对电机在电网电压跌落情况下的运行状况作理论分析，并提出采用主动式Crowbar电路来保护转子侧变流器和发电机本身的方案。在MATLAB／Simulink建立的风电场模型中进行电网电压深度跌落情况下的仿真研究。仿真结果表明，该电路可以有效限制电压跌落时转子回路产生的最大电流，保证系统各元件的安全，同时也证明了故障期间风电机组控制策略的有效性。该方案能实现故障期间交流励磁双馈异步风力发电机不脱网运行，并能起到稳定电网电压的积极作用。

英文摘要：

Based on the analysis of the grid code of wind turbine, a mathematical model of the doubly-fed induction machine （DFIG） wind turbine is built and the control policy is analyzed on the condition of grid＇s symmetrical operation. Then the DFIG wind turbine＇s operation is analysed in theory at the condition of grid voltage declines. The paper brings forward a scheme that taking the Crowbar-protect circuit to protect rotor excitation source and generator itself. The circuit is used to test its effectiveness by simulating at the wind farm model built in MATLAB/Simulink. From the simulation results, the circuit could ensures the safety of system components by limiting the maximum current generated by the rotor circuit at the time of voltage declines and also it is proved that the wind turbine＇s control strategy during the fault is effective. In a conclusion, this solution could make the ac excitation of DFIG wind turbine not divorced itself from grid when grid voltage declines and play a positive role in stabting the grid voltage.