Abstract：Modular multilevel converter (MMC) is one of the excellent selections for high voltage and high power conversion applications without transformers. It provides the advantages such as high modularity, availability, low generation of harmonics, etc. However, the circulating current distorts the leg currents and increases the rated current of power devices, which further increases system cost. By controlling the circulating current as CCVS (current controlled voltage sources), this paper derived the circulating current model of MMC. Then the quantitative relationship between the circulating currents and dc-bus current is derived and modified considering the actual characteristics of the circulation system. Further, this paper also reveals the existence of low-frequency components in the circulating currents. It means that MMC is suitable for the need to achieve negative sequence balancing applications.
杨晓峰, 王晓鹏, 范文宝, 郑琼林. 模块组合多电平变换器的环流模型[J]. 电工技术学报, 2011, 26(5): 21-27.
Yang Xiaofeng, Wang Xiaopeng, Fan Wenbao, Zheng Qionglin. Circulating Current Model of Modular Multilevel Converters. Transactions of China Electrotechnical Society, 2011, 26(5): 21-27.
[1] Dorn Joerg, Huang Hartmut, Retzmann Dietmar. Novel voltage-sourced converters for HVDC and FACTS applications[C]. CIGRE Symposium, Osaka Japan, 2007: 1-8. [2] 李庚银, 吕鹏飞, 李光凯, 等. 轻型高压直流输电技术的发展与展望[J]. 电力系统自动化, 2003, 27(4): 77-81. [3] Andersen B R, Xu L, Horton P J, et al. Topologies for VSC transmission[J]. Power Engineering Journal, 2002, 16(3): 142-150. [4] Gemmell B, Dorn J, Retzmann D, et al. Prospects of multilevel VSC technologies for power transmission[C]. Transmission and Distribution Conference and Exposition, Chicago, USA, 2008: 1-16. [5] Marquardt Rainer, Lesnicar Anton, Hildinger Jürgen. Modulares stromrichterkonzept für netzkupplungsan- wendung bei hohen spannungen[C]. ETG-Fachtagung, Bad Nauheim, 2002: 1-7. [6] Glinka M, Marquardt R. A new AC/AC multilevel converter family[J]. IEEE Transactions on Industrial Electronics, 2005, 52(3): 662-669. [7] Glinka M, Marquardt R. A new single phase AC/AC- multilevel converter for traction vehicles operating on AC line voltage[C]. European Conference on Power Electronics and Applications, France, 2003: 1-10. [8] Ding Guanjun, Tang Guangfu, He Zhiyuan, et al. New technologies of voltage source converter (VSC) for HVDC transmission system based on VSC[C]. IEEE Power and Energy Society General Meeting- Conversion and Delivery of Electrical Energy in the 21st Century, Pittsburgh, USA, 2008: 1-8. [9] Hagiwara M, Akagi H. Control and experiment of pulse width-modulated modular multilevel converters[J]. IEEE Transactions on Power Electronics, 2009, 24(7): 1737-1746. [10] 杨晓峰, 孙浩, 支刚, 等. 双星型模块组合型多电平变换器的PWM控制策略[J]. 电力电子, 2010(2): 14-19, 25. [11] 屠卿瑞, 徐政, 郑翔, 等. 模块化多电平换流器型直流输电内部环流机理分析[J]. 高电压技术, 2010, 36(2): 547-552.
2011, Vol. 26 
