Consensus-Based Distributed Control for Photovoltaic-Battery Units in a DC Microgrid

In this paper, a distributed cooperative control scheme, considering the state-of-charge balance and power limits of battery-storage units (BSUs) in the consensus protocol, is proposed to achieve the average bus voltage consensus in a dc microgrid with photovoltaics. The state variable defined in the consensus protocol enables all BSUs to charge or discharge together without introducing circulating currents among BSUs. Furthermore, by incorporating power limits of BSUs in the defined state variable, power violation of the BSUs can be prevented. The consensus-based distributed control only utilizes neighbor-to-neighbor communication to realize the global consensus, and, thus, avoids the single point of the failure compared to the conventional centralized control. Simulation and experimental results demonstrate the efficacy of the proposed method in an islanded dc microgrid under different testing scenarios.