An Equivalent Differential Method for Active Damping of LCL Type Grid-Connected Inverters With Grid-Side Inductor Voltage Feedback

作者：Mingming Li, Yinwei Ren, Huafeng Xiao, Chenghui Niu, Ming Cheng · 发表于：IEEE Transactions on Power Electronics · 年份：2023 · DOI：10.1109/tpel.2023.3252163 · 被引用次数：15 · 研究领域：Microgrid Control and Optimization、Power Systems and Renewable Energy、HVDC Systems and Fault Protection

The differential feedback of grid-side inductor voltage can effectively increase the damping of grid-connected inverters. Compared with proportional feedback of filter capacitor current, it can increase the output impedance of the grid-connected inverters, which is more conducive to reducing the impact of grid background harmonics on the grid-in current. However, there is a differential link in its damping branch, and existing differential implementation methods were pursuing to be ideal differential in wide frequency band, as a consequence, high-frequency components of the grid-side inductor voltage are amplified, which affects the quality of grid-in current. For this reason, this article proposes a band-pass filter in series with a lead compensation unit to replace the ideal differential. The major advantage different from the conventional methods is that the proposed strategy is only equivalent to the ideal differential around the resonance frequency band. Specifically, it features lower gain at low- and high-frequency bands. Finally, theoretical analysis and experiment results show that the proposed strategy can reduce the influence of the added damping path on th fundamental component of grid-in current and features better suppression effect on the harmonics.