Voltage stabilization in DC microGrids through coupling-independent Plug-and-Play controllers

This paper addresses the problem of stabilizing voltages in DC microgrids given by the interconnection of Distributed Generation Units (DGUs), power lines and loads. As in [1], we propose a decentralized control architecture where the controller of each DGU can be designed in a Plug-and-Play (PnP) fashion by solving a local Linear Matrix Inequality (LMI) problem. However, differently from [1], when a new DGU issues a plug-in request, we no longer require that neighboring units update their local controllers in order to account for new electrical couplings. Indeed, a key feature of the novel approach is that the design of a local controller requires only the knowledge of the dynamics of the corresponding DGU. The proof of closed-loop asymptotic stability combines properties of graph Laplacians, structured Lyapunov functions and LaSalle invariance theorem. Theoretical results are backed up by simulations in PSCAD.