Impedance modeling and stability analysis of single‑phase grid‑connected inverter considering frequency coupling

Authors

Ning XIAO, School of Electrical & Information Engineering，Changsha University of Science & Technology，Changsha 410114，China
Ci TANG, School of Electrical & Information Engineering，Changsha University of Science & Technology，Changsha 410114，ChinaFollow
Xuyi KUANG, School of Electrical & Information Engineering，Changsha University of Science & Technology，Changsha 410114，China
Min LUO, School of Electrical & Information Engineering，Changsha University of Science & Technology，Changsha 410114，China
Jiayi WANG, School of Electrical & Information Engineering，Changsha University of Science & Technology，Changsha 410114，China

Keywords

frequency coupling, single-phase grid-connected inverter, phase-locked loop, output impedance, stability analysis

Abstract

With the permeability increase of renewable energy, the interaction between power electronic converters and power grid causes oscillation accidents frequently. In order to study the characteristics of oscillation induced by grid-connected new energy sources, this paper explains the mechanism that a single-frequency disturbance voltage as input to a single-phase inverter considering the PLL effect leads to double-frequency disturbance current as output, through the relationship of real number signal and complex vector. The mechanism of frequency coupling in weak power grid is further explained. The models of self-admittance and mutual-admittance are established, and the equivalent output admittance of inverter is then derived. Finally, the correctness of the self-admittance and mutual-admittance models are verified by MATLAB/Simulink. The equivalent output impedance of inverter can be utilized to judge the stability of an interconnected system according to the Nyquist stability criterion.

DOI

10.19781/j.issn.1673-9140.2024.01.026

First Page

251

Last Page

259

Recommended Citation

XIAO, Ning; TANG, Ci; KUANG, Xuyi; LUO, Min; and WANG, Jiayi (2024) "Impedance modeling and stability analysis of single‑phase grid‑connected inverter considering frequency coupling," Journal of Electric Power Science and Technology: Vol. 39: Iss. 1, Article 26.
DOI: 10.19781/j.issn.1673-9140.2024.01.026
Available at: https://jepst.researchcommons.org/journal/vol39/iss1/26