Centralized-Decentralized Control Scheme for Power Sharing in Multiple PV-Battery System

To reducing the dependency on fossil fuels, there has been a significant shift towards use of renewable energy sources (RESs), particularly solar photovoltaic (PV), leading to the development of microgrids (MGs) within existing distribution systems. The intermittency of PV energy generation is managed with battery storage solutions. Effective control in these MG systems is critical for handling fluctuating power production, ensure optimal balanced power sharing among multiple parallel PV systems, accommodating to time-varying load demands, and prioritizing essential loads during energy shortages. This work gives a centralized-decentralized secondary controller (CDSC) aimed at synchronizing the operations of multiple PV-battery (PVB) units in the MG. Here, the centralized secondary controller (CSC) analyzes settings based on data from the local controller (LC), while the decentralized secondary controller (DSC) uses information from both the CSC and LC measurements to establish reference points for the LC. The CDSC design also takes into account for the actual power output from the PV array and incorporates constraints on the battery's charging/discharging currents, thereby extending the batteries lifespan. This control scheme is rigorously tested across various operational scenarios on a European distribution network using the PSCAD/EMTDC platform. The results suggests it is successful in achieving local distributed generation (DG) controllability as well as global optimality over the distribution network.