A Control Methodology of Inverter-Based Battery Energy Storage System for AC Microgrid

Control Methodology of inverter-based Battery Energy Storage System (BESS) is a key issue for the operation of AC microgird. In this paper, the voltage-mode control of inverter is considered and the control scheme of inverter for BESS is presented. Virtual synchronous generator is a core function and the frequency droop control and Automatic Voltage Regulator (AVR) form the outer cascade loops. The resynchronization of microgrid is rigorously studied, the concept of vector Phase-Locked-Loop (PLL) is adopted and formed as the outside cascade loop. Simulation is conducted by a pilot-site microgird at Mae Hong Son, Thailand, where a 4 MW/1 MWh BESS is designed. During the grid-connected mode, the default function of BESS is spinning reserve operation, while BESS can help forming the grid throughout the islanding mode. In addition, the proposed control technique of BESS can make the transition between grid-connected and islanding modes seamlessly.