A Hybrid Criterion Based Balancing Strategy for Battery Energy Storage Systems

Balancing is considered as the inevitable method to cope with the unbalanced problem, which commonly exists in series connected battery energy systems (BESSs). Balancing strategies could be categorized as the voltage based balancing strategy (VBBS), the state of charge (SOC) based balancing strategy (SBBS) and the capacity based balancing strategy (CBBS). In this study, a hybrid criterion based balancing strategy (HCBBS) is proposed, in which the advantages of both the VBBS and the SBBS are taken. Thus, the balancing can be carried out throughout the whole SOC range, accelerating the balancing procedure. The proposed HCBBS is deduced and analyzed. To validate the proposed method, the simulation is established. By comparing to the VBBS, the proposed HCBBS owns 50% improvements in balancing speed.