This paper proposes decentralized stability conditions for multi-converter systems based on the combination of the small gain theorem and the small phase theorem. Instead of directly computing the closed-loop dynamics, e.g., eigenvalues of the state-space matrix, or using the generalized Nyquist stability criterion, the proposed stability conditions are more scalable and computationally lighter, which aim at evaluating the closed-loop system stability by comparing the individual converter dynamics with the network dynamics in a decentralized and open-loop manner. Moreover, our approach can handle heterogeneous converters' dynamics and is suitable to analyze large-scale multi-converter power systems that contain grid-following (GFL), grid-forming (GFM) converters, and synchronous generators. Compared with other decentralized stability conditions, e.g., passivity-based stability conditions, the proposed conditions are significantly less conservative and can be generally satisfied in practice across the whole frequency range.
@article{arxiv.2309.08037,
title = {Gain and Phase: Decentralized Stability Conditions for Power Electronics-Dominated Power Systems},
author = {Linbin Huang and Dan Wang and Xiongfei Wang and Huanhai Xin and Ping Ju and Karl H. Johansson and Florian Dörfler},
journal= {arXiv preprint arXiv:2309.08037},
year = {2024}
}