基于VDCG的直流微电网退役锂电池SOC均衡方案  

SOC balancing scheme for lithium batteries in a DC microgrid based on VDCG

作　　者：吴青峰 褚晓林 刘立群[1] 胡秀芳 薄利明 WU Qingfeng;CHU Xiaolin;LIU Liqun;HU Xiufang;BO Liming(College of Electronic Information Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;Electric Power Research Institute of State Grid Shanxi Electric Power Company,Taiyuan 030001,China)

机构地区：[1]太原科技大学电子信息工程学院,山西太原030024 [2]国网山西省电力公司电力科学研究院,山西太原030001

出　　处：《电力系统保护与控制》2024年第15期14-23,共10页Power System Protection and Control

基　　金：国家重点研发计划项目资助(2018YFA0707305);山西省基础研究计划面上项目资助(202203021221153);阳泉市应用基础研究计划项目资助(2022JH059)。

摘　　要：为增加系统惯性,直流微电网内锂电池控制器常采用虚拟直流发电机(virtual DC generator,VDCG)控制方案,但该方案无法使锂电池荷电状态(state of charge,SOC)自均衡。现有基于VDCG的锂电池SOC均衡方案仅能实现电压等级一致的非等容锂电池SOC均衡,而退役锂电池储能系统(retire lithium battery energy storage systems,RLBESS)的容量和电压等级均难以保持一致。针对此问题,提出了一种基于VDCG的适用于不同电压等级及容量的RLBESS组间SOC均衡方案。该方案在传统VDCG的基础上建立U-P_(m)关系式并引入SOC均衡因子,能够根据初始SOC状态自动调节锂电池的功率分配,并保持良好的电压质量。建立了所提方案的小信号模型,分析了关键控制参数对系统稳定性的影响。最后,利用Matlab/Simulink仿真软件对不同工况进行有效性验证。仿真结果表明:所提方案能够在锂电池电压等级不一致工况下实现RLBESS的SOC均衡,具有良好的可扩展性。In order to increase system inertia,a virtual DC generator(VDCG)control scheme is often used for lithium battery controllers in DC microgrids,but this scheme cannot achieve self-balancing of the state of charge(SOC)of the lithium battery.The existing SOC equalization scheme based on VDCG for lithium batteries can only achieve SOC equalization for non-capacity lithium batteries with the same voltage level,while it is difficult to maintain the same capacity and voltage level of retired lithium battery energy storage systems(RLBESS).In response to this issue,this paper proposes a SOC equalization scheme for RLBESS with different voltage levels and capacities based on VDCG.This scheme establishes a U-P_(m) relationship based on traditional VDCG and introduces an SOC balance factor,which can automatically adjust the power distribution of lithium batteries based on the initial SOC state,while maintaining good voltage quality.A small-signal modeling of the proposed scheme is established,and the influence of key control parameters on the system stability is analyzed.Finally,the effectiveness of the proposed scheme is verified in different working conditions by using Matlab/Simulink simulation software.The simulation results show that the proposed scheme can achieve SOC balancing of RLBESS under inconsistent voltage levels of lithium batteries,with good scalability.

关 键 词：直流微网 退役锂电池 虚拟直流发电机 荷电状态均衡 小信号模型 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM912