Energy management system for an Islanded Micro-grid combining PV, battery and variable load

Abstract

This paper proposes a Perturb and Observe (P&O)-based Energy Management System (EMS) for an islanded micro-grid composed of photovoltaic (PV) generation, battery storage, and variable load demand. The EMS employs a hierarchical control strategy that leverages the P&O algorithm to optimize PV power extraction while coordinating battery charging and discharging operations. Specifically, when the battery state of charge (SOC) is low and the system encounters a power shortfall, the EMS directs all available renewable energy exclusively to recharge the battery, thereby improving resilience and extending autonomous operation. Conversely, in the case of energy surplus and a high SOC, the EMS suspends maximum power tracking and limits PV generation to balance production with demand, thus preventing overcharging and ensuring system safety. Under normal conditions, the EMS dynamically allocates PV generation between direct load supply and storage through P&O-based maximum power point tracking, ensuring efficient energy use and minimizing curtailment. Simulation results demonstrate that the proposed P&O-based EMS effectively stabilizes the micro-grid, enhances energy self-sufficiency, and guarantees reliable operation under variable solar irradiance and load conditions.