Modeling and Control of a Grid-Connected PV System with Battery Energy Storage for Grid Stability Enhancement

This paper presents a comprehensive modelling and coordinated control strategy for a grid-connected photovoltaic system integrated with a 550 V battery energy storage system. The intermittent nature of solar generation introduces significant challenges in maintaining DC-link stability and smooth power injection into the utility grid. To address these issues, a coordinated control architecture is developed employing perturb and observe maximum power point tracking for the PV subsystem and a bidirectional DC-DC converter for battery power buffering. The complete system is implemented in a Simulink environment using average-value converter models to achieve computational efficiency while preserving dynamic accuracy. Simulation results demonstrate that in the absence of BESS, the DC bus exhibits large power oscillations ranging approximately from 130 kW to 520 kW under multi-stage irradiance variations. With BESS integration, the DC-link voltage is tightly regulated around its nominal reference of approximately 550 V with minimal ripple, and the grid power is maintained close to the scheduled value of approximately 300 kW with negligible fluctuation. The results clearly quantify the effectiveness of battery energy storage in buffering renewable intermittency, stabilizing DC-link dynamics, and improving the dispatchability of grid-connected photovoltaic systems.