一种组合换流器内部直流电压均衡控制方法  

An Internal DC Voltage Balancing Control Method Suitable for Assembly Converter

作　　者：宣佳卓 王先为 刘启建 吴金龙[3] 姚为正 XUAN Jiazhuo;WANG Xianwei;LIU Qijian;WU Jinlong;YAO Weizheng(State Grid Zhejiang Electric Power Research Institute,Hangzhou 310014,China;Xi’an Xuji Power Electronics Technology Corporation,Xi’an 710075,China;Xuji Group Corporation,Xuchang 461000,China;XJ Electric Co.,Ltd.,Xuchang 461000,China)

机构地区：[1]国网浙江省电力有限公司电力科学研究院,浙江杭州310014 [2]西安许继电力电子技术有限公司,陕西西安710075 [3]许继集团有限公司,河南许昌461000 [4]许继电气股份有限公司,河南许昌461000

出　　处：《智慧电力》2019年第1期6-12,共7页Smart Power

基　　金：国家重点研发计划资助项目(2016YFB0900900);国家电网公司科技项目(5211011600R4)~~

摘　　要：模块化多电平换流器(MMC)适用于高压大容量柔性直流输电系统,采用基于MMC的组合换流器拓扑是提升直流输电电压等级和容量的有效手段之一。首先,分析了组合换流器的拓扑和稳态基本控制策略,以及系统直流电压扰动时各换流单元的能量和电压变化趋势,指出其稳态运行时存在串联换流单元电压不均衡问题;然后,提出在定功率站附加电压均衡控制策略,即在有功控制通道上叠加一个均压控制量,以实现换流器内部直流电压的均衡控制和功率均分。最后,在PSCAD/EMTDC环境下搭建基于MMC换流单元的组合换流器双端直流系统仿真模型,仿真结果验证了所提控制策略的有效性。Modular multilevel converter(MMC)is suitable for high voltage bulk power flexible direct current transmission system.To improve the voltage level and transmission capacity of HVDC,the MMC based assembly converter is one of the most effective methods.Based on the topology and steady state control strategy of assembly converter,the energy and voltage variation trend of each basic converter units are analyzed when the DC voltage disturbance happens.Then the voltage unbalance among series converter units is pointed out.For this problem,an additional voltage balance strategy is proposed.In fixed power converter station,a voltage deviation value is added on the active control channel.In this case,the power and DC voltage of each basic converter units can get average distribution.A two terminal simulation model of the assembly converter based on PSCAD/EMTDC is built,and the effectiveness of the proposed control scheme is verified by the time-domain simulation.

关 键 词：模块化多电平换流器 组合换流器 基本换流单元 电压均衡控制 

分 类 号：TM721[电气工程—电力系统及自动化]