An Improved SoC Balancing Strategy for Battery Energy Storage System in All-Electric Propulsion Ships Current Sharing Effect

A dynamic state of charge (SoC) balancing strategy for parallel battery energy storage units (BESUs) based on dynamic adjustment factor is proposed under the hierarchical control framework of all-electric propulsion ships, which can achieve accurate power distribution, bus voltage recovery, and SoC balance accuracy. In the primary control layer, the arccot function is introduced into the improved balancing strategy, and the bus voltage drop is effectively limited while the SoC balancing speed is quickly achieved by adjusting the SoC convergence factors. In the secondary control layer, power and voltage compensation controllers are designed individually to improve the SoC balance accuracy and compensate the bus voltage. Furthermore, neighbor-to-neighbor communication network is constructed by using dynamic consensus algorithm to reduce the communication burden as well as its error rate. Finally, the simulation and StarSim HIL experimental results show that the proposed control strategy can achieve accurate power distribution, bus voltage recovery, and has a faster SoC convergence speed than advanced methods.