摘要
微电网运行在孤岛模式下,光伏逆变器采用虚拟同步发电机(VSG)控制方式并联,各逆变器传输阻抗的差异及负载切换,会导致并联VSG无功功率分配不均问题。针对此问题,提出一种基于虚拟阻抗和动态下垂系数的无功均分组合控制策略。分析并联VSG的功率分配机理,通过线路阻抗观测器构造虚拟阻抗,引入VSG输出无功变量构造动态下垂系数,两者对VSG的输出电压进行自适应调整,控制逆变器输出的无功功率,实现无功功率按容量均分。仿真与实验结果表明所提控制策略将无功功率差值从317 var减小到66 var,无功功率输出偏差从16.7%减小到3.5%。
The microgrid operates in isolated island mode,and the PV inverters adopt virtual synchronous generator(VSG)control mode in parallel.The differences of transmission impedance and load switching of each inverter will lead to the unequal distribution of parallel VSG reactive power.To solve this problem,a reactive power equality-sharing combined control strategy based on virtual impedance and dynamic sag coefficient is proposed.The power distribution mechanism of parallel VSG is analyzed,the virtual impedance is constructed by the line impedance observer,and the dynamic sag coefficient is constructed by introducing VSG output reactive variable.The output voltage of the VSG is adjusted adaptively by both of them,and the output reactive power of the inverter is controlled,realizing the equal distribution of reactive power according to capacity.Simulation and experimental results show that the proposed control strategy reduces the reactive power difference from 317 var to 66 var and the reactive power output deviation from 16.7%to 3.5%.
作者
李小宝
李欣
李圣清
刘博文
LI Xiao-bao;LI Xin;LI Sheng-qing;LIU Bo-wen(Hunan University of Technology,Zhuzhou 412007,China)
出处
《电力电子技术》
北大核心
2023年第9期83-86,共4页
Power Electronics
基金
国家自然科学基金(51977072)
湖南省教育厅优秀青年项目(18B305)
关键词
微电网
虚拟同步发电机
无功均分
microgrid
virtual synchronous generator
reactive power sharing
作者简介
李小宝(1981-),男,讲师,研究方向为微电网逆变器控制;通信作者:李欣(1996-),男,硕士研究生,研究方向为微电网逆变器控制。
