基于反相层叠载波的三电平逆变器漏电流抑制和中点平衡方法  

A Modulation Strategy to Suppress Leakage Current and Balance Neutral Point Voltage for Three-level Inverters Based on Phase Opposition Disposition Carrier

作　　者：余天宝 万文超 付函 段善旭[1] YU Tianbao;WAN Wenchao;FU Han;DUAN Shanxu(State Key Laboratory of Advanced Electromagnetic Engineering and Technology,School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学电气与电子工程学院),武汉430074

出　　处：《高电压技术》2023年第5期2068-2076,共9页High Voltage Engineering

基　　金：国家重点研发计划(2018YFB0106300)。

摘　　要：三电平光伏逆变器的中点波动和漏电流会影响系统的可靠运行和输出质量。为此,提出了一种兼顾漏电流抑制和中点电压平衡的调制策略,在反相层叠载波的基础上通过特定零序分量注入将开关周期内共模电压峰峰值降为六分之一母线电压,波动频率降为开关频率,从而有效抑制漏电流;同时通过零序分量切换控制中点电流,平衡直流侧中点电位;根据判定电流方向,对调制波进行修正,避免死区对漏电流抑制的影响。最终通过实验验证了所提调制策略的可行性和有效性。Neutral-point(NP)voltage oscillation and leakage current in three-level solar inverters will affect the stable operation and output quality.For this reason,a novel modulation strategy is proposed in this paper to balance NP voltage and suppress leakage current.By the proposed scheme,the common-mode voltage(CMV)peak-to-peak value is reduced to the one sixth of the bus voltage and the CMV frequency is reduced to the switching frequency by injecting a specific zero-sequence voltage(ZSV)on the basis of phase opposition disposition(POD)carrier,thus the leakage current can be attenuated effectively.In order to balance NP voltage,NP current is adjusted by method of optimal ZSV selection.Moreover,the modulated waves are modified according to the output current to avoid the effect of dead time on CMV.Experiments are provided to verify the feasibility and validity of proposed modulation strategy.

关 键 词：三电平逆变器 漏电流 反相层叠载波 共模 中点平衡 

分 类 号：TM464[电气工程—电器]