Abstract：Under grid voltage unbalance conditions，active power deviations occur between the three phases of the cascaded energy storage converter，leading to unbalanced three-phase state of charge（SOC）and ultimately

reducing capacity utilization and system reliability. To address this issue，a control strategy based on the hybrid

injection of negative-sequence current and zero-sequence voltage was proposed. When zero-sequence voltage

injection alone cannot achieve SOC balance，the remaining power deviation was balanced through negativesequence current injection. This approach avoids the issue of excessive zero-sequence voltage injection causing output voltage distortion，and compares to using negative-sequence current injection alone，it also reduces the negative-sequence current flowing into the grid. This control strategy balances both phase-to-phase SOC balancing capability and the output power quality of the converter. Finally，the effectiveness of this approach was verified through simulation.

        Key words：cascaded energy storage converters；negative-sequence current injection；zero-sequence voltage

injection；state of charge（SOC）

     Format Citation:李志鹏，李嘉豪，王军,等. 电网不平衡工况下链式储能变流器SOC均衡控制方法研究[J].电气传动,2026,56(08):13-20. LI Zhipeng，LI Jiahao，WANG Jun,et al. Research on SOC balancing control method for cascaded energy storage converters under grid unbalanced conditions [J].Electric Drive, 2026,56(08): 13-20