Small-Signal Analysis of Current-Limiting Grid-Forming Inverters

Journal Article · Mon Jan 19 00:00:00 EST 2026 · IEEE Transactions on Industry Applications

DOI:https://doi.org/10.1109/TIA.2026.3655646· OSTI ID:3015908

Yang, Bowen ^[1]; Baeckeland, Nathan ^[1]; Seo, Gab-Su ^[1]

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1. National Laboratory of the Rockies, Golden, CO (United States)

Grid-forming (GFM) inverters are equipped with a current limiter to protect the device during grid disturbances. Because the intervention of the current limiter can compromise the transient stability of the GFM inverter, various types of current limiter designs and additional frequency-stabilization control methods have been proposed in recent literature to aid in transient GFM inverter stability; however, the small-signal stability implications of adding these additional control blocks during, in particular, off-nominal conditions are not fully understood. To address this challenge, this paper presents a generic small-signal model of a GFM inverter that incorporates various types of current limiters and frequency stability-enhancing controls. With the proposed model, we analyze the root causes of inverter instability, which reveals two critical design trade-offs. First, due to current-limiter engagement caused by a disturbance, the GFM inverter dynamics are altered, which can lead to voltage oscillations. Second, additional frequency-stabilization controls can improve the small-signal stability of the GFM inverter, but at the cost of reduced power and voltage support to the grid. Comprehensive hardware experiments validate the theoretical concept and analysis. The findings in this work underscore the importance of incorporating both transient-response and small-signal dynamics requirements into the design procedure of GFM current limiters and frequency-stabilization controls.

• Research Organization: National Laboratory of the Rockies (NLR), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office; USDOE National Laboratory of the Rockies (NLR), Laboratory Directed Research and Development (LDRD) Program
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 3015908
• Report Number(s): NLR/JA-5D00-92506
• Journal Information: IEEE Transactions on Industry Applications, Journal Name: IEEE Transactions on Industry Applications
• Country of Publication: United States
• Language: English

Related Subjects

24 POWER TRANSMISSION AND DISTRIBUTION
current limiting
frequency compensation
grid-forming inverters
limiter-induced voltage oscillation
small-signal stability