Impedance-Based Stability Analysis of Power Electronics Systems: Models, Metrics, and Advances

Date: 06/08/2026
Time: 9:00 am
Presenter: Marta Molinas
Abstract: (Sponsored by TC 5) The growing integration of renewable energy sources, connected to the grid through power converters, has introduced significant small-signal stability challenges. Power systems with high levels of power electronics have increasingly experienced oscillations across a broad frequency range, often triggered by small changes in operating conditions, control settings, or load. As converter penetration approaches 100% in parts of modern grids, these dynamic interactions pose a major risk to reliable operation, highlighting the need for effective diagnostic methods. Impedance-based stability analysis has become a practical and widely used approach due to its black-box nature, enabling engineers to assess stability margins through direct measurements of voltages and currents using frequency-scanning techniques, and to support stability-oriented converter design. This webinar introduces the fundamentals of impedance-based analysis, demonstrates its application through practical examples, and reviews recent developments in impedance modeling for multi-input multi-output (MIMO) systems. It concludes with a discussion of current challenges and future research directions in this important area.
Dr. Marta Molinas is currently a Professor in the Department of Engineering Cybernetics at the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway. She received her M.E. degree from Ryukyu University, Nishihara, Japan, in 1997, and her Doctor of Engineering degree from the Tokyo Institute of Technology, Tokyo, Japan, in 2000. Dr. Molinas was a Guest Researcher at the University of Padova, Italy, in 1998. From 2004 to 2007, she held a postdoctoral research position at NTNU, and from 2008 to 2014, she served as a Professor in the Department of Electric Power Engineering at the same institution. In 2014, she was a Visiting Scholar at Columbia University’s Earth Institute. She was also an invited fellow in Japan under the JSPS Invitational Fellowship in both 2008 and 2022. Her research interests include the stability of power electronic systems, harmonics, instantaneous frequency, and nonstationary signals from both human and machine sources. Prof. Molinas is an Editor for the IEEE Journal of Emerging and Selected Topics in Power Electronics (JESTPE), the IEEE Journal of Emerging and Selected Topics in Industrial Electronics (JESTIE), and Scientific Reports (Nature Publishing Group). She also serves as an Advisor to the Board of IEEE Electrification Magazine and as an Associate Editor for the IEEE Transactions on Power Electronics. She is a member of the Administrative Committee (AdCom) of the IEEE Transportation Electrification Council and previously served on the AdCom of the IEEE Power Electronics Society from 2009 to 2011. In 2016, Dr. Molinas was General Chair of IEEE COMPEL 2016, and Program Chair of IEEE PowerTech 2011. She is a Fellow of the IEEE.