A Multifunctional PV-BES-Utility System with Seamless Islanding and Resynchronization Capability

This work demonstrates a multifunctional solar photovoltaic (PV) system with a battery energy storage (BES). The system operates in grid connected mode by utilising a current control technique, and in the standalone mode using a voltage control strategy. When an anomaly is detected in the grid, the system swiftly disconnects from the grid, and when the normal grid resumes, the system resynchronizes to the grid. A boost converter extracts the maximum available PV power. The DC link voltage is maintained by a bidirectional DC-DC converter (BDDC), which interfaces the battery with the system. The power is fed to the load, and the grid using a voltage source converter (VSC). While in grid connected mode, the system performs grid power quality conditioning functions, and reduces the harmonic content in the grid current to meet the IEEE 519 standard. Experimental results are used to validate these capabilities of the system.