摘要
针对高压大容量模块化多电平换流器调制及子模块投切问题,提出了降低子模块电容电压排序运算量的分组排序调制方法。以电容电压排序运算量最优为目标,确定换流器桥臂子模块的最优分组数量;建立分组后的子模块电容电压矩阵,并对其进行组内纵向排序、组间横向排序,形成以子模块电容电压为序的子模块矩阵;每个控制周期,根据桥臂电流参数,按照子模块电压升高或降低方向,进行子模块投入、切除控制。同时引入子模块电容电压偏差控制,以防止电容电压偏差过大并降低功率器件开关频率。通过101电平柔性直流输电系统数字实时仿真,以及37电平的柔性直流输电系统物理动态仿真,得出提出的均压控制策略可以明显降低排序的运算量以及子模块的开关频率,并能保证子模块电容电压波动量维持在额定值的-5%-5%以内。
Aiming at the problems of high-voltage and high-capacity modular multilevel converter modulation and sub-modules switching, we propose a method of sorting by group to reduce the calculating capacity for ordering the sub-module capacitor voltage. Moreover, we determine an optimal number of groups of the converter arm sub-module so as to optimize the ordering calculating capacitance of the capacitor voltage. After the establishment of the sub-module capacitor voltage matrix, vertical sorting in each group and horizontal sorting between groups, a sub-module capacitor voltage ordered sub-module matrix is established. In each control cycle period, according to arm current parameters and sub-module voltage rise or decrease direction, switch sub-modules are set and controlled. Simultaneously, we introduce sub-module capacitor voltage deviation control to prevent the excessive capacitor voltage deviation and to reduce the power device switching frequency. Through digital simulation of a 101 level flexible HVDC transmission system and physical simulation of a 37 level flexible HVDC transmission system, it can be concluded that the voltage-sharing control strategy proposed in this paper can significantly reduce the amount of sequencing operations and the switching frequency of the sub-modules, and can ensure that the voltage fluctuation of the sub-module capacitor voltage is maintained within-5%-5% of the rated value.
作者
李国庆
王威儒
辛业春
王朝斌
江守其
LI Guoqing;WANG Weiru;XIN Yechun;WANG Chaobin;JIANG Shouqi(School of Electrical Engineering,Northeast Electric Power University,Jilin 132012,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2018年第7期2107-2114,共8页
High Voltage Engineering
基金
国家重点研发计划(2016YFB0900903)
国家自然科学基金(51607032)~~
关键词
模块化多电平换流器
分组排序
最优分组数量
子模块矩阵
电压均衡
开关频率
modular multilevel converter
sorting by group
optimal number of groups
sub-module matrix
voltagebalance
switching frequency
