基于改进虚拟惯量法的双馈风机频率综合控制策略

Integrated frequency control strategy of DFIGs based on improved virtual inertia method

针对双馈风机虚拟惯量控制的研究大多聚焦于转子转速恢复策略设计和控制参数优化,难以应对双馈风机出力骤降所带来的频率波动问题,本研究提出一种基于改进虚拟惯量法的频率综合控制策略,在双馈风机退出调频过程中,附加基于风机转速反馈的微分控制环节,降低转速恢复的速度,避免发生风机出力骤降,以抑制频率波动,同时综合超速控制,使双馈风机调频性能更优。在DIgSILENT/PowerFactory中搭建了仿真模型,对比验证了所提控制策略在不同场景下的有效性。算例结果表明,所提控制策略能够改进风机的惯量响应和一次调频特性,有效地避免频率快速变化。

The study of virtual inertia of the double fed induction generator(DFIG)mostly focused on the design of rotor speed recovery strategy and control parameter optimization,which was difficult to deal with the phenomenon of frequency fluctuations caused by the sudden decline of active power.This paper proposed an integrated frequency control strategy based on the improved virtual inertia control method.When the DFIG exited the frequency modulation process,the supplementary differential control link based on the turbine speed feedback was added to avoid the sudden drop of the active power of DFIG,delaying the recovery speed so as to suppress the rapid frequency fluctuation.The overspeed control was integrated to make the frequency modulation performance of DFIG better.A simulation model was built in DIgSILENT/PowerFactory,and the feasibility of the proposed control strategy was verified in different scenarios.The case study results showed that the proposed control strategy could improve the inertia response and primary frequency regulation,and avoid the fast change of frequency.