三电平背靠背变流器的中点电压波动分析与抑制  

Analyses and Restraining of the Neutral-Point Voltage Fluctuation in Back-to-Back Connected Three-Level Converters

作　　者：王颢雄[1,2] 马伟明[3] 肖飞[3] 陈明亮[3] 刘勇[3] 许跃宏 周峰 许锡盛[2] 

机构地区：[1]浙江大学电气工程学院,杭州310027 [2]大全集团凯帆电器股份有限公司,扬中212200 [3]海军工程大学电力电子技术研究所,武汉430033

出　　处：《电工技术学报》2013年第7期205-211,共7页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金创新研究群体项目(50721063)和国家自然科学基金(50737004)资助项目

摘　　要：三电平背靠背系统的中点电压同时受两侧变流器调制方式的影响。根据三电平变流器是否为直流电压自控制系统,变流器对中点电压的影响需采用不同的分析方法。同时,背靠背系统的工作点、两侧变流器不同的SVPWM实现方式、机侧与网侧基波电流的频率比、机侧与网侧的基波电流初始过零点的时间差均会对系统的中点电压平衡产生影响。本文根据三电平背靠背系统两侧变流器功能的划分,分析了机侧与网侧变流器采用不同的SVPWM组合方式对中点电压波动的影响。理论分析与仿真结果表明,当系统工作点位于Zone-A时,网侧采用虚拟矢量合成SVPWM(VVS),机侧采用最近三矢量合成SVPWM(NTV)这种组合方式具有较好的综合特性;在Zone-B,NTV(网侧)-VVS(机侧)具有较合适的调制方法。The neutral-point voltage of back-to-back connected three-level converters is simultaneously influenced by modulation method of two-side converters. Different methods should be used to analyze the neutral-point voltage balance according to whether the three-level converter is DC voltage self-controlled system. Meanwhile, working-point of converter, different combination mode of SVPWM used by two-side converters and the fundamental frequency ratio and initial zero-cross time-difference of fundamental current of two-side converter can all influence the neutral-point voltage of back-to-back system. Both of theoretical analysis and simulation result both indicates that VVS-NTV has better comprehensive performance if operation-point of the system lies in Zone-A and NTV-VVS is a more appropriate modulation method in Zone-B.

关 键 词：三电平变流器 背靠背 最近三矢量 虚拟矢量合成 中点电压 基波频率比两侧变流器基波电流初始过零点时间差 

分 类 号：TM46[电气工程—电器]