Plug-and-play control and consensus algorithms for current sharing in DC microgrids

In this paper, we propose a secondary consensus-based control layer for current sharing and voltage balancing in DC microGrids (mGs). Differently from existing approaches based on droop control, we assume decentralized Plug-and-Play (PnP) regulators at the primary level, as they provide voltage stabilization and their design complexity is independent of the mG size. We analyze the behavior of the closed-loop mG by approximating local primary control loops with unitary gains. This analysis can be extended to the more complex case where primary control loops are abstracted into first-order transfer functions (Tucci et al., 2016a). Besides showing stability, current sharing, and voltage balancing in the asymptotic régime, we describe how to design secondary controllers in a PnP fashion when Distributed Generation Units (DGUs) are added or removed. Theoretical results are complemented by simulations using a 5-DGUs mG implemented in Simulink/PLECS.