A Plug-and-Play Robust H∞ Voltage Tracking Control Strategy for Islanded AC Microgrids Based on Structured Matrix Decomposition

This article proposes a novel Plug-and-Play robustH∞control strategy for islanded AC microgrids composed of multiple interconnected distributed generation units (DGUs). The proposed control strategy aims to achieve both real-time voltage regulation at the point of common coupling to track given reference values and seamless Plug-and-Play operation. The Plug-and-Play capability ensures that controller gain updates are avoided when DGUs are added or removed from the system. First, different from existing methods that rely on prefilters or disturbance compensators for disturbance rejection, this article ingeniously employs parameter transformation to facilitate the application of the Elimination Lemma, thereby simplifying the controller synthesis process and ensuring the solvability of robustH∞controllers. Second, the interconnection coupling term is well approximated via structured matrix decomposition, the global stability of the studied system can be guaranteed based on local stability conditions. This effectively circumvents the restrictive matrix-structure assumptions required by some existing methods. Finally, two examples are presented to verify that the proposed method can effectively achieve both real-time voltage regulation and Plug-and-Play operation with satisfactory performance, validating its feasibility and superiority.