直流微电网分布式储能系统精确电流分配策略

在孤岛直流微电网中，需要采用储能系统（energy storage system，ESS）来维持发电和负载消耗之间的功率平衡。为了避免分布式储能单元（distributed energy storage units，DESU）的过度充放电，针对不同容量的分布式储能单元设计了基于自适应虚拟阻抗的荷电状态（state of charge, SOC）均衡策略。同时，提出了精确电流分配方法来消除不匹配线路电阻对SOC均衡的影响。通过所提方法，具有较高SOC的DESU在放电期间可向直流微电网提供更多的功率，反之亦然。此外，根据系统特征方程分析了所提方案的稳定性。最后，通过基于实时数字仿真系统（real time digital simulation，RTDS）的算例结果验证了所提控制策略的有效性。

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

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.