摘要
柔性直流输电系统一般采用模块化多电平MMC(modular multi-level converter)换流阀,换流阀开关频率的大小与系统损耗及交流侧谐波含量密切相关。推导了MMC开关频率与系统损耗及开关频率与柔性直流输电系统交流侧谐波含量的数学表达式;分析了MMC开关频率对系统损耗及交流侧谐波的影响规律。在此基础上,为了兼顾柔性直流输电系统的损耗和电能质量,采用遗传算法对开关频率进行了优化设计,根据工程经验对不同的优化目标赋予权值,根据国标要求设置了谐波和损耗的约束条件。仿真算例分析表明,采用优化的开关频率进行MMC变流控制时,柔性直流输电系统具有更佳的性能。
A modular multi-level converter(MMC)valve is usually used in a flexible DC transmission system,and the magnitude of the switching frequency is closely related to system loss and AC-side harmonic content.In this paper,the mathematic expressions of MMC switching frequency vs.system loss and switching frequency vs.AC-side harmonic content of the flexible DC transmission system are deduced,respectively;in addition,the influences of MMC switching frequency on system loss and AC-side harmonics are analyzed.On this basis,in consideration of the loss and power quality of the flexible DC transmission system,genetic algorithm is used to optimize the switching frequency.According to engineering experiences,different weights are given to the corresponding optimization objectives.Following the Chinese national standard,the constraint conditions of harmonics and loss are set.Simulation results show that the flexible DC transmission system has better performance when using the optimized switching frequency to control the MMC converter.
作者
荣飞
李文君
饶宏
周保荣
黄守道
RONG Fei;LI Wenjun;RAO Hong;ZHOU Baorong;HUANG Shoudao(College of Electrical and Information Engineering,Hunan University,Changsha 410082,China;State Key Laboratory of High Voltage Direct Current Transmission,Electric Power Research Institute,China Southern Power Grid,Guangzhou 510620,China)
出处
《电源学报》
CSCD
北大核心
2018年第6期84-91,共8页
Journal of Power Supply
基金
国家重点研发计划资助项目(2016YFB0901001)。
关键词
模块化多电平换流阀
损耗计算
谐波分析
线性加权权重
遗传算法
modular multi-level converter(MMC)valve
calculation of loss
harmonic analysis
linear weighted weight
genetic algorithm
