A novel energy control strategy for distributed energy storage system based on virtual current

•A novel energy control strategy for DESS is proposed, taking advantage of the fact that the slope of the arcsinh function is larger near zero to achieve SOC equalization rapidly.•A novel concept of virtual current is proposed to establish a bridge between SOC and output current, which is different from the virtual resistance in droop control, and virtual current does not cause a bus voltage drop.•Only one controller is required to achieve bus voltage restoration and current sharing, simplifying the control structure.•Compared with the previous control strategy, the proposed strategy in this article can achieve SOC equalization more quickly. This article proposes a novel energy control strategy for distributed energy storage system (DESS) to solve the problems of slow state of charge (SOC) equalization and slow current sharing. In this strategy, a key part of the presented strategy is the integration of a new parameter virtual current defined from SOC and output current. With the help of virtual current, the characteristic of the arcsinh function has a large slope near the zero point, and three acceleration factors, to realize the fast equalization of SOC and the output current quickly distributed by capacity. In addition, current sharing and voltage restoration can be achieved by designing only one controller, thereby simplifying the control structure. In communication layer, only two variables need to be exchanged between neighboring converters, thus, reducing the communication burden. Then, the stability of the system is analyzed by small signal modeling. Finally, the correctness and effectiveness of the proposed control strategy are verified through the experiments.