Coordinated Control of Parallel Three-phase Four-wire Converters in Autonomous AC Microgrids  

作　　者：Rui Liu Li Guo Xialin Li 

机构地区：[1]Key Laboratory of Smart Grid of Ministry of Education,Tianjin University,Tianjin 300072,China

出　　处：《CSEE Journal of Power and Energy Systems》2024年第5期2065-2078,共14页中国电机工程学会电力与能源系统学报（英文）

摘　　要：The coordinated control of parallel three-phase fourwire converters in autonomous AC microgrids is investigated in this paper.First,based on droop control,virtual impedance is inserted in positive-,negative-and zero-sequences to enhance system damping and imbalance power sharing.Then,to facilitate virtual impedance design,small signal models of the three-sequence equivalent circuits are established respectively.Corresponding indexes are proposed to comprehensively evaluate the impact of sequence virtual impedance on current sharing accuracy,voltage quality at the point of common coupling(PCC)and system stability.In addition,constraint of DClink voltage is also considered to avoid over modulation when subjected to unbalanced loads.Furthermore,to address the PCC voltage degradation resulting from virtual impedance,a voltage imbalance compensation method,based on low-bandwidth communication,is proposed.Finally,simulation and experimental results are provided to verify the correctness of the theory model,indicating that the proposed method can achieve PCC voltage restoration while guaranteeing the current sharing accuracy with desirable dynamics.

关 键 词：AC microgrids sequence virtual impedance three-phase four-wire(3P4W)converter voltage imbalance compensation 

分 类 号：TM46[电气工程—电器]