AUTHOR=Zhang Zhi , Li Yiyun , Zhong Caomao , Zhang Zhaoyun 

TITLE=Resonance suppression and quality improvement control strategy for a three-phase grid-connected voltage-source inverter under weak grid conditions

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2023.1231992

DOI=10.3389/fenrg.2023.1231992

ISSN=2296-598X

ABSTRACT=The three-phase voltage-source grid-connected inverters suffers from grid-connected current quality problem due to system resonance caused by the under-damping characteristics of the filter and grid impedance on the one hand, and the grid-connected current distortion caused by the high content of low harmonics in the grid voltage on the other hand. To resolve this problem, a current quality improvement control strategy combining capacitor-current feedforward active damping and harmonic virtual impedance reshaping is proposed in this paper by analyzing the mechanism of system resonance and grid-connected current distortion. It is also proposed to determine the virtual impedance parameters by using the root locus method, so as to achieve the purpose of improving the output grid-connected current quality of the three-phase voltage source grid-connected inverter under weak grid conditions. Finally, the correctness and effectiveness of the proposed control strategy are verified by simulation and experiment.