Scalable Fuzzy Control for Nonlinear DC Microgrids Under Plug-and-Play Operations

The plugging-in/-out of renewable distributed generation units (DGUs) often alters the microgrid size and coupling terms, resulting in computational burdens and voltage shocks. This article proposes a novel scalable fuzzy voltage control scheme for nonlinear direct current microgrids (DCmGs) composed of DGUs and constant power loads (CPLs) interconnected via power lines. First, a Takagi-Sugeno fuzzy DCmG model with CPL is formulated to capture nonlinear characteristics and diverse transient behaviors. Then, a scalable fuzzy control approach is developed to mitigate negative coupling effects of power lines. This is achieved by a novel argument that leverages dissipativity theory to transform such effects into linear matrix inequalities and subsequently imposes constraints on their sequential principal minors. Specifically, the proposed control method operates locally and independently of other DGUs and line couplings, enabling seamless plug-and-play operations without updating any controllers. Finally, theoretical results are validated through simulations using the MATLAB/SimPowerSystems toolbox.