三角形连接链式STATCOM三倍频环流优化研究  

Optimization of the Triple-Harmonic Circulating Current for Delta-Connected Cascaded STATCOM

作　　者：宋强[1] 魏伟 黎小林 许树楷 刘文华[1] 

机构地区：[1]电力系统及发电设备控制和仿真国家重点实验室(清华大学电机系),北京市海淀区100084 [2]南方电网科学研究院,广东省广州市510080

出　　处：《电网技术》2015年第8期2364-2370,共7页Power System Technology

基　　金：国家863高技术基金项目(2011AA05A102)~~

摘　　要：三角形连接链式STATCOM的三相桥臂之间存在三倍频环流,为分析三倍频环流的大小及其影响和优化控制方法,首先提出了基于循环耦合关系的解析分析方法,该方法可准确计算出换流器的三倍频环流;其次,应用该解析方法分析了三倍频环流的存在对于链节电容电压波动的影响,并进一步提出了以降低链节电容电压波动和减小所需电容值为目标的三倍频环流优化控制方法,该控制方法可以有效降低装置的体积和成本;最后,通过仿真验证了所提出的解析分析方法和三倍频环流优化控制方法的有效性。For a STATCOM using delta-connected cascaded multilevel converter, there exists a triple-harmonic circulating current flowing through the three-phase legs. To calculate its value and analyze its impacts and optimization control methods, an analytical analysis method for delta-connected STATCOM is proposed at first. The impacts of the circulating current on concerned electrical quantities are analyzed. The analysis especially reveals that the circulating current has significant impact on the capacitor ripple voltage. To decrease the capacitor ripple voltage and reduce the required capacitance, a method for eliminating the circulating current in delta-connected cascaded converter is proposed. To further reduce the capacitor ripple voltage, a control method that reverses the direction of circulating current is also proposed. The proposed method can effectively reduce the required capacitance, and therefore reduce the size and cost of the STATCOM. The exactness of the proposed analysis method and the feasibility of the proposed optimization method are verified with simulation.

关 键 词：链式换流器 静止无功发生器 三倍频环流 电容电压波动 三角形连接 

分 类 号：TM721[电气工程—电力系统及自动化]