A Robust Consensus Algorithm for Current Sharing and Voltage Regulation in DC Microgrids

In this paper, a novel distributed control algorithm for current sharing and voltage regulation in DC microgrids is proposed. The DC microgrid is composed of several distributed generation units, including buck converters and current loads. The considered model permits an arbitrary network topology and is affected by an unknown load demand and modeling uncertainties. The proposed control strategy exploits a communication network to achieve proportional current sharing using a consensus-like algorithm. Voltage regulation is achieved by constraining the system to a suitable manifold. Two robust control strategies of sliding mode type are developed to reach the desired manifold in a finite time. The proposed control scheme is formally analyzed, proving the achievement of proportional current sharing, while guaranteeing that the weighted average voltage of the microgrid is identical to the weighted average of the voltage references.

I. Introduction

In the past decades, due to economic, technological, and environmental aspects, the main trends in power systems focused on the modification of the traditional power generation and transmission systems toward incorporating smaller distributed generation units (DGUs). Moreover, the ever-increasing energy demand and the concern about the climate change have encouraged the wide diffusion of renewable energy sources (RES). The so-called microgrids have been proposed as conceptual solutions to integrate different types of RES and to electrify remote areas. Microgrids are low-voltage electrical distribution networks, composed of clusters of DGUs, loads, and storage systems interconnected through power lines [2].