A Non-intrusive Decentralized Approach to Stabilizing IBR-dominated AC Microgrids

This paper presents a non-intrusive, decentralized approach that stabilizes AC microgrids dominated by inverter-based resources (IBRs). By "non-intrusive" we mean that the approach does not require reprogramming IBRs' controllers to stabilize the microgrids. "Decentralized" is in the sense that the approach stabilizes the microgrids without communication among IBRs. Implementing the approach only requires very minimal information of IBR dynamics, i.e., the L2 gain of an IBR, and sharing such information with the non-IBR-manufacturer parties does not cause any concerns on intellectual property privacy. The approach allows for plug-and-play operation of IBRs, while maintaining microgrid stability. The proposed approach is tested by simulating 2-IBR and 10-IBR microgrids where lines and IBRs are modeled in the electromagnetic transient time scale. Simulations show that oscillations with increasing amplitudes may occur, when two stable microgrids are networked. Simulations also suggest that the proposed approach can mitigate such a system-level symptom.