Title: Analytical framework of complex dynamics of interacting grid converters

Mr Ziyang Miao, University of Science and Technology China, Hefei

Abstract: Dynamic interactions between grid-forming converters (GFMCs) and grid-following converters (GFLCs) can induce sustained subsynchronous oscillations, whose modal characteristics are strongly influenced by network parameters. Previous studies have shown that, depending on network conditions, GFLC may predominantly synchronize with either GFMC or the power grid. In this talk, we investigate the nonlinear mechanisms underlying these oscillations from a geometric perspective. By employing geometric singular perturbation theory (GSPT), we rigorously characterize the geometric structure of the system's critical manifold and systematically analyze the resulting trajectory dynamics across different parameter regimes. Building on these theoretical insights, we propose a novel quantitative criterion and develop a unified classification framework that distinguishes five distinct oscillation modes.

Speaker's Bio: Ziyang Miao is currently a Ph.D. student in the School of Mathematical Sciences at University of Science and Technology of China, under the supervision of Prof. Yi Wang. He is also a Research Assistant in Department of Electrical Engineering at City University of Hong Kong, under the supervision of Prof. Michael C. K. Tse. He received his B.Sc. degree from the School of Mathematics and Statistics at Northeast Normal University in 2023. His research focuses on nonlinear dynamics in renewable energy power systems.