Dispatchable power source control for battery bank charging through a bidirectional grid forming converter in isolated microgrid

Abstract

Energy storage systems with batteries are critical points in isolated microgrids. Charging depends on the manufacturing technology, the methodology established by the manufacturer, and must be controlled depending on the voltage and current, considering the state of charge of the batteries, the power sources, and the load. In this work, a control for a dispatchable power source connected to the distribution network for charging battery banks in isolated microgrid is proposed, considering the dynamics of a distributed generation system. This control was implemented through a PAC (Programmable Automation Controller), considering two main charging approaches: a) a full battery bank charging, made when the battery state of charging reach the minimum permitted level, and b) a partial battery bank charging, made when the 90% of the maximum state of charging is not reached in the day. A real and consolidated system was used as a case study: this system is the isolated microgrid with generation distributed in Ilha Grande, northeastern Brazil.