提高双馈风电机组LVRT能力的改进直接功率控制

双馈风力发电系统采用传统直接功率控制时，在发生低电压穿越(LVRT)后转子电流振荡较大，易引起Crowbar再动作。建立传统直接功率控制下双馈风力发电系统的模型，对矢量控制和直接功率控制抑制LVRT的效果进行分析，在此基础上提出一种改进型直接功率控制方法。引入谐振调节器消除定子磁链动态分量对转子磁链的作用，抑制Crowbar切除后转子电流的动态分量，从而改善双馈风电机组LVRT特性。仿真比较验证了所提控制方法应用于双馈风力发电系统的可行性，该控制方法比矢量控制使系统更快恢复稳定，且比传统直接功率控制对转子电流振荡抑制效果更明显。

Modified direct power control for improving LVRT ability of doubly fed induction generator

When the traditional DPC(Direct Power Control) is adopted in doubly fed induction generator system, the large rotor oscillation current after LVRT(Low-Voltage Ride-Through) may cause re-operation of Crowbar. The model of doubly fed induction generator system with traditional DPC is built, and the restraining effect of LVRT with vector control and DPC is analyzed, on this basis, an improved DPC method is proposed. The resonant controller is introduced to eliminate the impact of stator flux dynamic component on rotor flux, restrain the rotor flux dynamic component after cutting out Crowbar, thus improving LVRT characteristic of doubly fed induction generator. Simulation and comparison verify the feasibility of the proposed control method in doubly fed induction generator system, the proposed method makes the system recover stability more quickly than vector control, and has more obvious effect on restraining rotor current oscillation than the traditional DPC.