A Decentralized Scalable Approach to Voltage Control of DC Islanded Microgrids

We propose a new decentralized control scheme for DC Islanded microGrids (ImGs) composed of several Distributed Generation Units (DGUs) with a general interconnection topology. Each local controller regulates the voltage of the point of common coupling of the corresponding DGU to a reference value. Notably, offline control design is conducted in a plug-and-play fashion, meaning that: 1) the possibility of adding/removing a DGU without spoiling the stability of the overall ImG is checked through an optimization problem; 2) when a DGU is plugged in or out, at most its neighboring DGUs have to update their controllers; and 3) the synthesis of a local controller uses only information on the corresponding DGU and lines connected to it. This guarantees the total scalability of control synthesis as the ImG size grows or DGUs get replaced. Yet, under mild approximations of line dynamics, we formally guarantee the stability of the overall closed-loop ImG. The performance of the proposed controllers is analyzed simulating different scenarios in PSCAD.