A battery management system for a small microgrid system

Microgrid systems, electric vehicles and portable devices need batteries as storage devices and power sources. Therefore, battery management system (BMS) is critical for maintaining optimum battery performance. In this paper, a BMS designed for a battery system of a small microgrid system in Taiwan is described. To validiate the concept, a scale-down experimental battery system is tested by the proposed BMS. For charging strategies, both two-step and multi-stage charging methods are described. Regarding the state-of-charge estimation, direct open circuit voltage (OCV), coulometric, OCV prediction, and neural network (NN) estimation methods are delineated and compared. The results indicate that NN method performs the best for predicting the state of charge.