模块化多电平变换器与三电平变换器于低压光伏并网系统的应用对比  

A comparison of modular multilevel converters and three-level converters in low-voltage photovoltaic grid-connected system

作　　者：金辰璐[1] 张兴[1] 周岩峰[2] 

机构地区：[1]合肥工业大学电气与自动化工程学院,安徽合肥230009 [2]阳光电源股份有限公司,安徽合肥230088

出　　处：《合肥工业大学学报（自然科学版）》2014年第5期543-550,共8页Journal of Hefei University of Technology：Natural Science

基　　金：国家自然科学基金面上资助项目(51277051)

摘　　要：文章针对以模块化多电平变换器(MMC)替代传统的三电平变换器作为低压光伏并网系统入网接口的设想,参考已有的15kW三相三电平光伏逆变器,设计输入输出条件与之对等的15kW三相MMC光伏逆变器,利用Matlab软件搭建两者的并网仿真模型,得到MMC在并网性能方面的优势。分析给出2种光伏逆变器导通损耗与开关损耗的估算方法,并在逆变器模型的运行过程中完成不同负载条件下的损耗实时估算。估算结果表明MMC光伏逆变器的通态损耗与三电平光伏逆变器相比偏高,但其开关损耗却很低。2种逆变器主电路的转换效率基本相同,前者于轻载工况略有优势,后者的优势则体现在额定负载点附近区域。Aiming at the assumption of applying modular multilevel converters（MMC）as an alternative to traditional three-level converters in low-voltage photovoltaic grid-connected system,a 15kW threephase modular multilevel photovoltaic inverter is designed referring to the existing 15kW three-phase three-level photovoltaic inverter under the restraint of having same input and output conditions.The grid-connection simulation models of the two inverters are built by Matlab software and the simulation results show that MMC has good grid performance.The methods for estimating the conduction losses and switching losses of the two inverters are given and the real-time loss estimation under varying load conditions is completed in the operating process of the inverters models.It is indicated that compared with three-level photovoltaic inverter,the modular multilevel photovoltaic inverter has higher conduction losses but lower switching losses.Their conversion efficiency is nearly the same,but MMC shows a little advantage in the case of light load,while three-level converter does better in the case of rated load.

关 键 词：模块化多电平变换器(MMC) 三电平变换器 MATLAB软件 损耗估算 低压光伏并网系统 

分 类 号：TM46[电气工程—电器]