Battery State of Charge Balancing with Accurate Power Sharing in DC Microgrid

This paper proposes a distributed control method to achieve state of charge (SoC) balancing among the distributed battery energy units (BEUs) in a DC microgrid based on accurate power sharing. The distributed control algorithm estimates the average SoC of all BEUs by means of consensus algorithm, and voltage regulation is determined by comparing the per unit power of BEU with the those of the neighbors. At the same time, the estimated average SoC and the voltage regulation are used to implement accurate power sharing according to the SoC levels of BEUs to achieve the SoC balancing regardless of the line resistance difference. Moreover, the control algorithm also restores the DC voltage level to the nominal value for stable operation. The effectiveness of the proposed method is proved by simulation.