State-of-Charge Balancing for Battery Energy Storage Systems in DC Microgrids by Distributed Adaptive Power Distribution

Abstract

We consider the control problem of fulfilling the desired total charging/discharging power while balancing the state-of-charge (SoC) of the networked battery units with unknown parameters in a battery energy storage system. We develop power allocating algorithms for the battery units. These algorithms make use of distributed estimators for the average desired power and the average unit state and the adaptive parameter estimators, and are showed to fulfill the desired total power while achieving battery unit SoC balancing as long as the undirected graph that represents the communication network among the battery units is connected and there is at least one battery unit with the knowledge of the desired total power. Numerical simulation verifies the effectiveness of the proposed power allocating algorithms.