Analysis and control of large-signal stability with storage in small scale islanded AC microgrids

Abstract

The analysis of small-signal stability in AC microgrids has yielded numerous findings. However, investigating large-signal stability remains a major difficulty and has received limited attention in research. The article presents the establishment of a non-linear reduced-order model for small-scale AC microgrids with storage. The model considers the changes in converter structure that occur during large disturbances. Next, we will analyse the system’s stability under large-signal conditions and identify the underlying unstable mechanism. The impact of limitation links on system stability is significant, as they result in structural changes. The proposal of “virtual synchronous damping control” (VSD) aims to improve the stability of AC microgrids by addressing the issues caused by an unstable mechanism. The validation of the proposed analysis and control methods are demonstrated by examining relevant case studies in MATLAB/Simulink.