Revisiting Voltage and Synchronization Stability Analysis in Converter-Integrated Weak Grids: Insights from Non-Minimum-Phase Zeros

Fuente: arXiv
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Main Authors: Ma, Fuyilong, Zhang, Lidong, Tang, Wangqianyun, Zheng, Waisheng, Xin, Huanhai, Huang, Linbin, Harnefors, Lennart
Format: Preprint
Published: 2026
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_version_ 1866910215541096448
author Ma, Fuyilong
Zhang, Lidong
Tang, Wangqianyun
Zheng, Waisheng
Xin, Huanhai
Huang, Linbin
Harnefors, Lennart
author_facet Ma, Fuyilong
Zhang, Lidong
Tang, Wangqianyun
Zheng, Waisheng
Xin, Huanhai
Huang, Linbin
Harnefors, Lennart
contents The increasing penetration of converter-interfaced generators (CIGs) intensifies concerns over small-signal voltage and synchronization stability. While existing theories treat these two stability issues distinctly, practical wisdom in contrast employs a unified and static metric, short-circuit ratio (SCR), to assess both in weak grids. This paper aims to bridge this theory-practice gap by introducing the insight of non-minimum phase (NMP) zeros. First, we demonstrate that the two stability issues in weak grids originate from NMP zeros in the grid Jacobian transfer matrix: a zero at the origin corresponds to voltage instability, while low-frequency zeros impose fundamental constraints on synchronization dynamics. The traditional SCR is proven to be a special case of our proposed novel stability metric, NMP-zero (NMP-Z) factor, evaluated at the rated operating point. This establishes the theoretical foundation for the empirical success of SCR. Building on this insight, we then develop a unified stability assessment method for multi-converter systems. The method retains the simplicity of SCR, requiring only the NMP-Z factor together with individual CIG dynamic models and enabling stability margin assessment under various operating points. Our work provides a simple yet theoretically rigorous framework for stability analysis in CIG-integrated weak grids, with all theoretical findings and the proposed method validated through detailed time-domain simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2605_13061
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Revisiting Voltage and Synchronization Stability Analysis in Converter-Integrated Weak Grids: Insights from Non-Minimum-Phase Zeros
Ma, Fuyilong
Zhang, Lidong
Tang, Wangqianyun
Zheng, Waisheng
Xin, Huanhai
Huang, Linbin
Harnefors, Lennart
Systems and Control
The increasing penetration of converter-interfaced generators (CIGs) intensifies concerns over small-signal voltage and synchronization stability. While existing theories treat these two stability issues distinctly, practical wisdom in contrast employs a unified and static metric, short-circuit ratio (SCR), to assess both in weak grids. This paper aims to bridge this theory-practice gap by introducing the insight of non-minimum phase (NMP) zeros. First, we demonstrate that the two stability issues in weak grids originate from NMP zeros in the grid Jacobian transfer matrix: a zero at the origin corresponds to voltage instability, while low-frequency zeros impose fundamental constraints on synchronization dynamics. The traditional SCR is proven to be a special case of our proposed novel stability metric, NMP-zero (NMP-Z) factor, evaluated at the rated operating point. This establishes the theoretical foundation for the empirical success of SCR. Building on this insight, we then develop a unified stability assessment method for multi-converter systems. The method retains the simplicity of SCR, requiring only the NMP-Z factor together with individual CIG dynamic models and enabling stability margin assessment under various operating points. Our work provides a simple yet theoretically rigorous framework for stability analysis in CIG-integrated weak grids, with all theoretical findings and the proposed method validated through detailed time-domain simulations.
title Revisiting Voltage and Synchronization Stability Analysis in Converter-Integrated Weak Grids: Insights from Non-Minimum-Phase Zeros
topic Systems and Control
url https://arxiv.org/abs/2605.13061