双馈型风力发电机机组（doubly-fed induction generator，DFIG）可通过超速减载获得有功功率备用来参与调频，但由于DFIG有最低转速限制，在转速恢复时可能导致严重的频率二次跌落。针对这一问题提出了一种基于双向DC/DC变流器和超级电容器储能参与调频的策略。首先基于DFIG传统超速减载调频原理，分析了其可能产生频率二次跌落的原因和后果。然后，结合超级电容器和DFIG网侧变流器的运行特性，将超级电容器通过DC/DC变流器接口并联在DFIG背靠背变流器直流母线上，利用DFIG网侧变流器协同超级电容器的储能特性来参与调频，有效避免了频率的二次跌落，达到良好的调频效果。最后，通过仿真验证了所提方法的有效性与优越性。

The doubly-fed induction generator(DFIG) unit can obtain active power reserve by overspeed load shedding to participate in frequency modulation, but due to the minimum speed limit of DFIG, it may cause serious secondary frequency drop when speed is recovered. To solve this problem, a frequency modulation strategy is proposed based on bidirectional DC/DC converter and supercapacitor energy storage. Firstly, based on the traditional overspeed load shedding and frequency modulation principle of DFIG, the causes and consequences of secondary frequency drop are analyzed. Then, combined with the operation characteristics of the supercapacitor and the DFIG grid-side converter, the supercapacitor is connected in parallel to the DC bus of the DFIG back-to-back converter through the DC/DC converter interface, and the DFIG grid-side converter collaborates with the energy storage characteristics of the supercapacitor to participate in frequency modulation, effectively avoiding the secondary frequency drop and achieving good frequency modulation effect. Finally, the effectiveness and superiority of the proposed method are verified by simulation.