SOC Balancing Strategy for Distributed Energy Storage System Based on Improved Resistive Droop Control

doi:10.3969/j.issn.1008-0198.2024.02.014

Abstract

Abstract: During the operation of low voltage microgrid,due to the inconsistency of the initial state of distributed energy storage units and the impedance difference of the output line,unbalanced state of charge (SOC) is easy to occur when the traditional resistive droop control is adopted.Therefore, the SOC balancing strategy for energy storage system based on improved resistive droop control is proposed in this paper.Firstly,the dynamic virtual complex impedance is introduced to eliminate the impedance difference of the output line of each inverter,and the power decoupling of the resistive droop control is realized and the active power is precisely equalized.Then,the traditional resistance droop control equation is improved,and the droop coefficient is adjusted adaptively by SOC changes of each distributed energy storage units to ensure SOC balance of each energy storage unit in the low-voltage microgrid during the charge and discharge process,and the voltage and frequency deviation in the droop control process is compensated to further improve the stability of the system.Finally,a simulation model is built to verify the effectiveness of the proposed strategy.

Key words: low-voltage microgrid, DESU, resistive droop control, SOC balancing

CLC Number:

TM91

YAN Shi, TAN Haiyang, XIAO Hua, CHEN Ci, LI Shengqing. SOC Balancing Strategy for Distributed Energy Storage System Based on Improved Resistive Droop Control[J]. Hunan Electric Power, 2024, 44(2): 104-111.

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