模块化多电平换流器不对称桥臂的环流稳态分析  

Steady-state analysis of unsymmetrical MMC bridge-arm circulating current

作　　者：韩少华[1] 梅军[1] 郑建勇[1] 吉宇[1] 杜晓舟[1] 

机构地区：[1]东南大学电气工程学院,江苏南京210096

出　　处：《电力自动化设备》2014年第7期38-42,共5页Electric Power Automation Equipment

基　　金：教育部博士点基金资助项目(20130092110041)~~

摘　　要：在模块化多电平换流器(MMC)上下桥臂的电阻、电感不对称情况下,其桥臂环流的主要成分不再仅包括直流量和2次分量,因此有必要对此时的MMC桥臂环流进行定量研究。通过悬浮电容电压的变化规律,从时域角度构建描述环流特征的二阶微分方程。在稳态情况下忽略微分方程的通解,通过近似处理方法求得微分方程的特解,该特解可以有效地描述环流的稳态特性,即此时环流的主要成分为直流分量、1次分量和2次分量,还给出了此时环流的稳态表达式。通过MATLAB/Simulink平台搭建了仿真模型,仿真结果验证了理论分析的正确性和有效性。If the resistors and inductors of the upper and lower MMC（Modular Multilevel Converter） bridge- arms are unsymmetrical,the main ingredients of its circulating current will not include only the DC component and the second harmonic component,which should be quantitatively studied. A time-domain second-order differential equation is built according to the variation rules of flying capacitor voltage. Under the steady-state condition,its general solution can be ignored and its special solution is achieved by approximation,which describes the steady-state characteristics of circulating current effectively and shows the steady-state circulating current of unsymmetrical MMC bridge-arm contains mainly the DC component,first harmonic component and second harmonic component. Its steady-state expression is also presented. The simulation model is built with MATLAB/Simulink and the simulative results verify the correctness and effectiveness of theoretical analysis.

关 键 词：模块化多电平换流器 不对称 桥臂环流 二阶微分方程 稳态 换流器 

分 类 号：TM46[电气工程—电器]