Stability Analysis of Multi-Paralleled Grid-Connected Inverters with LCL-Filter in the Weak Grid

In this paper, the stability problem of multi-paralleled grid-connected inverter system in the weak grid is investigated. Due to the existence of grid impedance, the inverters in the system have coupling problems with each other. This may cause resonance and lead the system to be unstable. This pape...

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Bibliographic Details
Published inIECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society Vol. 1; pp. 3937 - 3942
Main Authors Jin, Yinglin, Fang, Tianzhi, Shen, Shuheng, Zhu, Shushu
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.10.2019
Subjects
Circuit stability
digital-control-delay
Impedance
Inductors
Inverters
LCL-filter
multi-paralleled grid-connected inverters
Power system stability
stability analysis
Stability criteria
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Summary:In this paper, the stability problem of multi-paralleled grid-connected inverter system in the weak grid is investigated. Due to the existence of grid impedance, the inverters in the system have coupling problems with each other. This may cause resonance and lead the system to be unstable. This paper focuses on the general system of inverters with different parameters, and then establishes the Norton equivalent model of the system. Based on the equivalent transformation of the Norton model, the grid impedance is equivalently allocated to each inverter, and a stability criterion for a multi-paralleled grid-connected inverter system is proposed. In addition, considering the influence of the digital-control-delay on system stability, a phase-lead compensator is added to the capacitor-current-feedback path to improve the system robustness against grid impedance variation. The effectiveness of the theoretical analysis is verified by experimental results.
ISSN:2577-1647
DOI:10.1109/IECON.2019.8927623