Frequency-coupling Admittance Modeling and Measurement Method of Grid-connected Inverters Considering Phase Dependence

作者：Zipeng Gao, Guochun Xiao, Pengkun Ji, Xianghao Cao, Lintao Xiao, Yuanyuan Tian · 年份：2023 · DOI：10.1109/icpet59380.2023.10367538 · 被引用次数：1 · 研究领域：Microgrid Control and Optimization、Islanding Detection in Power Systems、HVDC Systems and Fault Protection

Impedance-based method is an effective method to analyze the interactive system stability of a grid-connected inverter and grid. The impedance/admittance modeling and measurement of the grid-connected inverter are two important parts of the impedance-based method. However, the phase dependence characteristics is not considered in the existing most admittance modeling and measurement of the grid-connected inverter, leading to challenges to the model validation and stability analysis. In this paper, the frequency-coupling admittance model of a three-phase grid-connected inverter is first established by using harmonic linearization method, which points out the phase of off-diagonal elements are dependent on the initial phase of the fundamental voltage. Then, the impact of the phase dependence characteristics on the existing frequency-coupling admittance measurement method is analyzed particularly. Furthermore, a practical and flexible measurement method that can eliminate the impact of the phase dependence and maintain the accuracy and consistency of each measurement for the frequency-coupling admittance of the grid-connected inverter is proposed. Finally, simulations verify the correctness of the theoretical analysis and the effectiveness of the proposed measurement method.