Small-Signal Stability Analysis of an Inverter-Based Microgrid With Internal Model-Based Controllers

Several microgrid control strategies are proposed and studied in the literature. However, there are still gaps in improving their transient behavior and studying their stability. This paper uses small-signal analysis to explore the behavior of internal model-based current and voltage controllers by deriving a state-space model and performing eigenvalue and sensitivity analysis on an islanded inverter-based microgrid system. The results are compared with those of the same microgrid but with PI-based current and voltage controllers. Simulation case studies are performed in the PSCAD/EMTDC environment to compare the transient behavior of both methods. Results show that internal model-based controllers have superior eigenvalue patterns that lead to increased stability and improved transient behavior.