摘要
为了通过扩大线性调制区实现模块化多电平换流器(modular multilevel converter,MMC)运行特性和体积成本的优化,分析了3次谐波注入和全桥子模块负电平输出对MMC线性调制区的影响,建立了综合计及3次谐波注入和负电平利用因素的MMC线性调制区统一分析模型,得到了综合计及两方面因素影响的最大调制比解析表达式。建立了桥臂功率波动随调制比变化的解析分析模型,揭示了在有功功率工况下桥臂基频功率波动随调制比的提高存在一个极低点。基于一个400 kV/1250 MW的MMC实例,对几种线性调制区扩大方式对MMC参数设计和桥臂功率波动的影响进行了对比分析,通过3次谐波注入和负电平利用的协调配合,可以使MMC调制比运行在最优点附近,大幅降低子模块电容电压波动。数字仿真结果验证了所提分析模型的正确性,并表明了3次谐波注入和负电平利用的协调优化运行方式的有效性。
In order to optimize characteristics,cost and volume of modular multilevel converter(MMC)through expanding linear modulation region,the influence of third-order harmonic voltage injection and negative voltage level utilization of full-bridge submodules on the linear modulation region of MMC is analyzed comprehensively.A unified analysis model of the linear modulation region of MMC is established,and an analytical expression of the maximum attainable modulation index of MMC considering both the factors of third-order harmonic voltage injection and negative voltage level utilization is obtained.Moreover,an analytical analysis model of the power fluctuation of the arm with the variation of modulation index is established,which reveals that there is a minimal point of the fundamental frequency power fluctuation with the increase of the modulation index under the active power condition.Based on a 400 kV/1250 MW MMC example,the influences of several schemes for expanding linear modulation region on the MMC parameter design and arm power fluctuation and capacitor voltage ripples are compared and analyzed.Through the coordination of the third-harmonic injection and negative voltage level utilization,the modulation index can be operated near the optimal value,and the submodule capacitor voltage fluctuation can be greatly reduced.Digital simulation results verify the correctness of the proposed analysis model,and show the effectiveness of the feasibility of the third-harmonic injection and negative voltage level utilization.
作者
周月宾
宋强
张楠
高盛
孟经伟
ZHOU Yuebin;SONG Qiang;ZHANG Nan;GAO Sheng;MENG Jingwei(State Key Laboratory of HVDC,China Southern Power Grid Electric Power Research Institute,Guangzhou 510663,China;State Key Laboratory of Power System and Generation Equipment,Tsinghua University,Beijing 100084,China;Maintenance and Test Center of Extra High Voltage Power Transmission Co.,China Southern Power Grid,Guangzhou 510663,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2021年第12期4451-4460,共10页
High Voltage Engineering
基金
南方电网公司科技项目(ZBKJXM20180663)
国家重点研发计划(2016YFB0901005)。
关键词
模块化多电平换流器
柔性直流输电
3次谐波电压注入
全桥子模块负电平利用
线性调制区
modular multilevel converter
flexible DC power transmission
third-order harmonic voltage injection
negative voltage level utilization of full-bridge submodules
linear modulation region
