基于改进型P-E下垂控制的低压交流微电网不同容量储能单元SOC均衡策略

SOC BALANCING STRATEGY OF LOW VOLTAGE AC MICROGRIDS WITH DIFFERENT CAPACITIES BASE ON IMPROVED P-E DROOP CONTROL

针对现有基于有功-电压(P-E)下垂控制的荷电状态(SOC)均衡方案未考虑容量差异对分布式储能单元(DESU)SOC均衡影响且SOC均衡过程伴随着电压质量下降的问题,提出适用于不同容量DESU的SOC均衡策略。分析传统P-E下垂控制工作特性,得到SOC、电压和频率调节机理。在P-E下垂控制中引入SOC、电压和频率调节项,并引入多代理技术计算SOC调节项中的SOC平均值。改进后的P-E下垂控制在无需中央控制器/本地脉冲控制器和不影响电压质量的前提下,消除不同容量DESU组间SOC不均衡差,并克服负荷波动引起的电压下降和频率上升问题。建立所提方案小信号模型,通过分析根轨迹确保设置的控制参数保持系统稳定。仿真模型和实验平台获得的仿真和实验结果证实提出策略的可行性。

Aiming at the problem that the existing state of charge(SOC)balancing scheme based on active-voltage(P-E) droop control does not consider the influence of capacity difference on SOC balancing of distributed energy storage unit(DESU)and that the SOC balancing process is accompanied by voltage quality degradation,a SOC balancing strategy for different capacity DESU is proposed.The operating characteristics of traditional P-E droop control are analyzed,and the regulation mechanism of SOC,voltage and frequency is obtained.In the P-E droop control,the SOC,voltage and frequency regulation terms are introduced,and the multiple agent technology is introduced to calculate the average value of SOC in the SOC regulation terms.The improved P-E droop control eliminates the imbalance of SOC between DESU groups with different capacities and overcomes the problems of voltage drop and frequency rise caused by load fluctuation without requiring the central controller/local pulse controller and affecting the voltage quality.The small signal model of the proposed scheme is established,and the root locus is analyzed to ensure that the set control parameters keep the system stable.The simulation and experimental results obtained by the simulation model and experimental platform confirm the feasibility of the proposed strategy.