Large Signal Stability Assessment for Islanded MGs with A Mix of Grid-Following and Grid-Forming Inverters: A Networked Oscillators-Based Approach

This letter proposes a networked oscillators-based approach to analyze the large-signal stability of inverter-dominated microgrids (MGs). Compared with the conventional methods, the proposed analysis is applicable to islanded MGs with a mix of grid-following (GFL) and grid-forming (GFM) inverters. The equivalent networked oscillator model of such MGs with a general topology is developed, and the system's frequency stability domain is analytically derived. A stability evaluation scheme is proposed accordingly and its effectiveness has been validated on a Controller Hardware-in-the-Loop (C-HIL) testbed for multi-inverter applications.