为了增强直流微电网中分布式储能系统的惯性,并在线路阻抗不匹配的情况下实现各储能单元(energy storage unit,ESU)的荷电状态(state of charge,SOC)均衡,提出一种基于虚拟直流电机(virtual DC machine,VDCM)的分布式储能系统能量动态分配策略.首先,将VDCM技术应用到储能侧控制中,利用VDCM的输出特性增强系统的抗扰能力.然后,利用电枢回路方程输出特性,并根据储能系统能量分配需求,动态设计虚拟电枢电阻,使其可随SOC在规定界限内自适应变化,实时调整各变换器的输出功率,并引入压降调节因子动态微调各变换器输出虚拟压降至相等,从而补偿线路阻抗的不匹配度,实现各ESU的SOC.均衡.此外,采用一致性算法在相邻ESU间获得所需平均值信息,增强系统的可扩展性.最后,搭建光伏多储能直流微电网系统模型,仿真和实验结果验证了所提控制策略的合理性和有效性.
Energy Dynamic Allocation Strategy of Distributed Energy Storage System Based on Virtual DC Machine
To enhance the inertia of the distributed energy storage system in the DC microgrid,and achieve the state of charge(SOC)balance of each energy storage unit(ESU)in the case of line impedance mismatch,a dynamic energy allocation strategy of distributed energy storage system based on virtual DC machine(VDCM)was proposed.Firstly,the VDCM technology was applied to the energy storage side control using the output characteristics of VDC to enhance the anti-interfer-ence capability of the system,then,using the output character-istics of the armature loop equation to dynamically design the virtual armature resistance according to the energy distribution demand of the energy storage system,so that it can adaptively change with the SOC within the specified limits,and the output power of each converter in real-time,and the voltage drop ad-justment factor was introduced to dynamically fine-tune the vir-tual voltage drop of each converter to be equal,so as to com-pensate for the mismatch degree of the line impedance and real-ize the SOC equalization of each ESU.Secondly,a consensus algorithm was used to obtain the required average value inform-ation between adjacent ESUs,which improves the scalability of the system.Finally,a photovoltaic multi-energy storage DC mi-crogrid system model was built,and the simulation and experi-mental results verify the rationality and effectiveness of the pro-posed control strategy.
DC microgridstate of charge(SOC)virtual DC machine(VDCM)distributed energy storage systemdynamic energy distributionvirtual armature resistanceDC bus voltagevoltage drop adjustment factor
国家科技期刊平台
NSTL
万方数据
