载波交替层叠调制下三电平变流器中点自平衡能力分析与改进拓扑  

Neutral-point Potential Self-balancing Analysis and Improved Topology of Three-level Converter WithAPOD Modulation

作　　者：陈鹏飞[1] 唐芬[1] 赵宇明 吴学智[1] 王玮[1] Poh Chiang LOH CHEN Pengfei;TANG Fen;ZHAO Yuming;WU Xuezhi;WANG Wei;Poh Chiang LOH(National Active Distribution Network Technology Research Center(Beijing Jiaotong University),Haidian District,Beijing 100044,China;Shenzhen Power Supply Co.,Ltd.,Shenzhen 518048,Guangdong Province,China;Department of Electronic Engineering,Chinese University of Hong Kong,Hong Kong 999077,China)

机构地区：[1]国家能源主动配电网技术研发中心(北京交通大学),北京市海淀区100044 [2]深圳供电局有限公司,广东省深圳市518048 [3]香港中文大学电子工程系,中国香港999077

出　　处：《电网技术》2021年第2期758-767,共10页Power System Technology

基　　金：中国南方电网有限责任公司科技项目(090000KK52180116)。

摘　　要：针对三电平并网变流器中点电位不平衡导致并网电流低次谐波增加等问题,在定量分析基于载波交替层叠调制的三电平并网变流器谐波分布特性的基础上,得出传统拓扑并网电流和滤波电流中各次分量对中点电位的影响,给出中点自平衡能力的主要影响因素。针对传统自平衡时间较长的问题,提出改进中点自平衡拓扑,详细分析了自平衡机理、参数取值原则以及自平衡时间的影响因素。最后,仿真和实验结果表明改进拓扑在保证并网电流电能质量的同时,能够实现各种工况下中点电位的快速自平衡,与传统中点电位控制速度相当,可省去中点电位控制算法和传感器,易于实现,具有较好的经济性以及可靠性。Aiming at the problems of the increased low order harmonics in the grid connected current caused by the drift of neutral-point potential in three level grid-connected converter, the quantitative analysis of the harmonic distribution characteristics of three level grid-connected converter based on APOD modulation is conducted. The influence of each component of the conventional topological grid connected current and the filtered current on the neutral-point potential is deduced and the main influencing factors of neutral-point potential self-balancing ability are given. To address the issue that self-balancing time of the traditional topology is long, the improved topology is proposed by analyzing the self-balancing mechanism, the determined principle of parameter and the influencing factors of self-balancing time. Finally, the simulation and experimental results show that the improved topology can achieve both high grid-connected power quality and fast neutral point potential self-balancing, the speed of which is as fast as traditional neutral point potential control under various working conditions. In this way, the neutral point potential control algorithm and the related sensors can be removed. Therefore, the proposed topology is easy to be implemented and it presents better economy and reliability.

关 键 词：三电平 并网变流器 中点电位平衡 载波交替层叠 

分 类 号：TM721[电气工程—电力系统及自动化]