Robust AD for LCL‐type grid‐connected inverter with capacitor current quasi‐integral feedback

作者：Shiming He, Jian Xiong, Ze Wang, Shengchao Lin · 发表于：IET Power Electronics · 年份：2020 · DOI：10.1049/iet-pel.2019.0659 · 被引用次数：10 · 研究领域：Microgrid Control and Optimization、Islanding Detection in Power Systems、Advanced DC-DC Converters

Considering the time delay introduced by the digital control, it turns out that capacitor current proportional feedback active damping (AD) is equivalent to a frequency‐dependent virtual impedance in parallel with the filter capacitor. Unstable open‐loop poles will arise due to the presence of virtual negative resistor, which causes that the system stability is highly sensitive to grid‐impedance variation. Therefore, this study proposes a novel capacitor current quasi‐integral feedback AD method. Theoretical analysis shows the proposed AD method can extend the region of the virtual positive resistor, i.e. damping region to the half of sampling frequency ( f s /2). Hence, strong robustness against the grid‐impedance variation is achieved. Finally, experimental results including the proposed AD method as well as capacitor current proportional feedback AD method are given and compared, which validates the superior damping performance of the proposed scheme.