In this article, a small-signal model of grid-forming (GFM) converters that takes into account the presence of ac shunt capacitors in the power grid is presented. It is revealed that the inclusion of shunt ac capacitors in GFM converters leads to the emergence of two new resonant peaks in the loop gain of the active power control (APC) loop, in addition to the fundamental-frequency resonant peak that was previously identified in literature. Further analysis based on the equivalent APC considering P/Q coupling has confirmed the same destabilization effect of ac shunt capacitors by introducing two extra resonant peaks. Based on the insight, it is suggested that the active damping control needs to be adapted to effectively dampen all three resonant peaks to ensure the stable operation of GFM converters. Finally, simulations and real-time simulations are carried out to corroborate the theoretical findings.

中文翻译：

---

LC谐振栅极并网变换器的稳定性分析和主动阻尼设计

在本文中，提出了一种并网 (GFM) 转换器的小信号模型，该模型考虑了电网中交流并联电容器的存在。据透露，除了先前在文学。基于考虑 P/Q 耦合的等效 APC 的进一步分析通过引入两个额外的谐振峰证实了交流并联电容器具有相同的失稳效应。基于此，建议需要采用主动阻尼控制来有效抑制所有三个谐振峰值，以确保 GFM 转换器的稳定运行。最后，进行模拟和实时模拟以证实理论结果。