Accurate Current Sharing Strategy for Distributed Energy Storage System in DC Microgrids

doi:10.11930/j.issn.1004-9649.202201057

Abstract

Abstract: In islanded direct current (DC) microgrids, the power balance between power generation and load consumption must be maintained by the energy storage system (ESS). To avoid the over-charging or over-discharging of distributed energy storage units (DESUs), this study designs the state of charge (SOC) balancing strategy based on adaptive virtual resistance for DESUs with different capacities. Meanwhile, it proposes an accurate current sharing method to eliminate the impact of mismatched line resistance on SOC balancing. With the proposed strategy, the DESUs with high SOC can supply more power to DC microgrids than the DESUs with low SOC in the discharging period and vice versa. Additionally, the stability of the proposed scheme is analyzed according to the characteristic equation of the system. Finally, the results of calculation examples based on real-time digital simulation (RTDS) verify that the proposed control strategy is effective.

Key words: DC microgrid, energy storage system, state of charge, accurate current sharing, virtual resistance

WANG Bo, ZHANG Zhanying, ZHANG Xiao, XI Shengzhe, DENG Jin, MI Yang. Accurate Current Sharing Strategy for Distributed Energy Storage System in DC Microgrids[J]. Electric Power, 2022, 55(8): 96-103,112.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.202201057

https://www.electricpower.com.cn/EN/Y2022/V55/I8/96

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