基于下垂控制的逆变器无线并联与环流抑制技术  

Wireless Parallel and Circulation Current Reduction of Droop-Controlled Inverters

作　　者：陈杰[1] 刘名凹 陈新[1] 钮博文 龚春英[1] 张雅希 Chen Jie;Liu Ming’ao;Chen Xin;Niu Bowen;Gong Chunying(Jiangsu Key Laboratory of New Energy Generation and Power Conversion Nanjing University of Aeronautics&Astronautics,Nanjing 211106,China)

机构地区：[1]南京航空航天大学江苏省新能源发电与电能变换重点实验室,南京211106 [2]不详

出　　处：《电工技术学报》2018年第7期1450-1460,共11页Transactions of China Electrotechnical Society

基　　金：江苏省产学研合作前瞻性联合研究项目(BY2015003-05)和台达环境与教育基金会《电力电子科教发展计划》(DREG2016006)资助。

摘　　要：分析了逆变器并联系统的功率传输特性及其环流特性,指出在感性连线阻抗条件下,并联单元间线路阻抗差异和输出电压偏差对系统无功功率的均分精度有很大影响。为此,提出一种自适应虚拟阻抗方法,在保证等效连线阻抗主要呈现感性的同时,可减小等效线路阻抗之间的差异,改善功率分配精度。在此基础上,进一步提出一种改进型下垂控制策略,通过引入交流母线电压反馈,将等效下垂控制曲线设计为非线性函数,可有效协调功率均分精度与输出电压跌落之间的内在矛盾,抑制环流,提升并联系统整体性能。最后,仿真及实验结果验证了理论分析和所提控制策略的正确性和有效性。The power transmission and circulating current characteristics of a parallel-inverter system are firstly analyzed in this paper.It reveals that the difference of the line impedance and the deviation of the output voltages between two parallel units both have significant effects on the power sharing accuracy of reactive power under the condition of the inductive line impedance.An adaptive virtual impedance method is proposed to reduce the difference of the equivalent connection impedance of the parallel system to some extent,and the power sharing accuracy will be obviously improved by keeping the equivalent connection line impedance inductive.Additionally,an improved droop control strategy,which forms the equivalent droop control curve like a parabolic shape,is further put forward by using the feedback of AC bus voltage,realizing the trade-off between power sharing accuracy and output voltage sag effectively.With the proposed control strategy,the current circulation can be drastically suppressed and the system overall performance is greatly improved.Finally,the validity of the theoretical analysis and the proposed strategy is proved by simulation and experimental results.

关 键 词：下垂控制 虚拟阻抗 功率均分 环流 

分 类 号：TM464[电气工程—电器]