模块化多电平换流器电容电压与环流的控制策略  

Capacitor voltage and circulation current control strategy in modular multilevel converter

作　　者：高建[1] 苏建徽[1] 高航[1] 丁云芝 汪晶晶[1] 

机构地区：[1]合肥工业大学教育部光伏系统工程研究中心,安徽合肥230009

出　　处：《电力系统保护与控制》2014年第3期56-62,共7页Power System Protection and Control

摘　　要：电容电压控制和环流的抑制一直是模块化多电平换流器(MMC)拓扑研究很重要的一方面,也是制约该拓扑应用于柔性高压直流输电(HVDC)领域的瓶颈。分析了模块化多电平换流器电容电压波动以及环流偶次谐波产生的机理。在排序均压的载波移相调制(CPS-SPWM)策略的基础上,附加了电容电压均衡控制,以抑制电容电压的波动。同时介绍了一种闭环的谐振环流控制器,实现对环流交流成分的抑制。该控制策略结构简单,且适用于单相系统。仿真结果表明,采用上述的控制方法,电容电压的波动和环流都得到很好的抑制,动态结果也很好。Capacitor voltage control and circulation current suppression are of great importance in the research of MMC topology. In the meantime, they are also the bottleneck restricting the application of MMC topology in the field of flexible high voltage direct current （HVDC）. This paper analyzes generation mechanism of the capacitor voltage fluctuations and even harmonics circulation current in MMC. Based on the strategy of carrier phase-shift modulation （CPS-SPWM） by sorting and equalizing voltage, the capacitor voltage balance control is added so as to suppress the capacitor voltage fluctuation. In addition, the paper introduces a close-loop resonant circulation controller to realize suppression of AC component of the circulation current. This control method has simple structure and is suitable for single-phase system. Simulation results show that both the capacitor voltage fluctuation and circulation current can be well suppressed with the proposed method. The dynamic results are also good.

关 键 词：模块化多电平换流器 电容电压 环流 电压均衡控制 谐振控制器 

分 类 号：TM46[电气工程—电器]