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

Abstract

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.

Keywords

• Current sharing
• Distributed energy storage system (DESS)
• Energy control strategy
• State of charge (SOC)
• Stability analysis