适合于柔性高压直流输电系统的模块化多电平变流器的自适应均压方法  

An Adaptive Voltage Balancing Method of Modular Multilevel Converter for HVDC Transmission Systems

作　　者：赵聪[1] 李耀华[1] 李子欣[1] 王平[1] 徐飞[1] 王哲[1] 

机构地区：[1]中国科学院电力电子与电气驱动重点实验室(中国科学院电工研究所),北京市海淀区100190

出　　处：《电网技术》2017年第5期1510-1518,共9页Power System Technology

基　　金：国家自然科学基金青年科学基金项目(51507167)~~

摘　　要：提出一种模块化多电平变流器(modular multilevel converter,MMC)的自适应均压方法。在每个控制周期中,根据桥臂电流绝对值的大小选择不同个数的功率模块进行轮换。此外,还推导并计算了采用该自适应均压方法的功率器件平均开关频率的解析表达式。通过160 k V/400 MVA的MMC仿真系统验证了所提出的自适应均压算法的有效性和平均开关频率计算的正确性。最后,在RT-LAB实时仿真实验平台中搭建了350 k V/1000 MW的MMC背靠背系统,对上述方法进行了实验验证。实验结果表明,采用所提出的自适应均压方法能够在保证功率模块电容电压均衡的前提下降低开关频率,提高系统效率。This paper proposes an adaptive voltage balancing method for modular multilevel converter（MMC）. Different numbers of power modules are selected for alternating according to converter bridge arm currents and its derivatives in every control cycle. Analytical expression of average switching frequency is derived for the adaptive method. Effectiveness of the adaptive method and correctness of derivation of the average switching frequency are verified with simulations on a ±160 k V/400 MVA MMC system. Finally, a ±350 k V/1000 MW MMC back-to-back system is built with RT-LAB. Experimental results demonstrate that the average switching frequency can be reduced without affecting power module voltage balancing if the adaptive method is implemented.

关 键 词：模块化多电平变流器 自适应均压方法 平均开关频率 

分 类 号：TM76[电气工程—电力系统及自动化]