模块化多电平变换器研究综述  

Review of researching about modular multilevel converter

作　　者：谢瑞[1] 胡列翔[2] 徐建国[1] 周志超[1] 钱锋[1] 高志林[1] 

机构地区：[1]浙江省电力设计院,浙江杭州310012 [2]国网浙江省电力公司,浙江杭州310007

出　　处：《机电工程》2014年第12期1615-1622,共8页Journal of Mechanical & Electrical Engineering

摘　　要：针对模块化多电平变换器(MMC)的各种子模块拓扑结构,分析了其运行方式及特点,通过解析的方法得到了其输出和环流等效电路,并总结了各种子模块拓扑的应用场合。同时针对MMC不同的调制方法,利用精确的解析表达式对其线性度、谐波特性进行了比较分析。针对MMC不同的电容电压平衡策略,从系统成本、控制复杂度、系统损耗分布等方面进行了比较研究。介绍了国内已经建成的和正在建设的4条基于MMC的柔性直流输电工程,比较了这4条线路的电压等级、系统容量以及运行特点。研究结果表明,最近电平调制法简单、易实现,一般结合排序算法实现电容电压平衡,适用于子模块数较多的场合,载波移相法的等效开关频率较高,输出电压谐波小,可以利用闭环算法或者排序算法实现电容电压平衡,在子模块数较少时仍可适用。Aiming at comparing the different sub- modules of modular multilevel converter （MMC） , the operation process and characteristics were analyzed. The equivalent circuits of output voltage and circulating current were obtained by the detailed mathematical expressions. Also the applications of these different sub-modules of MMC were summarized. In order to compare the different modulation strategies, the accurate expressions were calculated to analyze their linearity and harmonic characteristics. Then the performances of different capacitor voltage balancing methods were concluded from the perspectives of system cost, controlling complexity and system loss distribution. The voltage level, system capacity and operation characteristics of four MMC based HVDC projects in China were compared with each other. The researching results indicate that nearest level modulation（NLM）method is easy to be realized and usually adopted for the large scale MMC with the capacitor voltage sorting algorithm. Carrier phase shift pulse width modulation（CPS-PWM）can obtain the performances of high equivalent switching frequency and low distortion, and can be used with capacitor voltage sorting algorithm or closed-loop balancing method even when the number of sub-modules is small.

关 键 词：模块化多电平变换器 直流输电 阶梯波调制 载波移相调制 电容电压平衡 

分 类 号：TM464[电气工程—电器]