A Capacitor Voltage Dynamic Balancing Method for Multilevel Converters Based on Taking Power from Capacitors

doi:10.3969/j.issn.1000-7229.2014.08.001

Abstract

Abstract: The capacitor voltage balancing problem of multilevel converters may result in the reduction of capacity utilization, the unstable operation and the deterioration of power quality. Based on taking power from capacitor, a dynamic resistance balancing device for multilevel converters and its control method were proposed, in which the dynamic equalizing resistance consisted of a low-voltage MOSFET and a resistance in series, and the power was taken from the capacitor through a DC-DC convertor with wide range voltage input. The turn on/off of low-voltage MOSFET was controlled by hysteresis comparison method or duty ratio control method, which could implement the dynamic balance control of multilevel converter's capacitor voltage. The increased cost of the device is very low, the control method is simple and easy to implement； it has strong universality and can be applied in all kinds of multilevel converters. Based on PSCAD/ EMTDC, the results show that the proposed dynamic resistance balancing device and control method can well realize the dynamic balancing control for the capacitor voltage of multilevel converter.

Key words: multilevel converter, dynamic balancing device for capacitor voltage, taking power from capacitor, hysteresis comparison control, duty ratio control

WEI Yingdong, ZHANG Chunpeng, YU Xinyu, JIANG Qirong. A Capacitor Voltage Dynamic Balancing Method for Multilevel Converters Based on Taking Power from Capacitors[J]. ELECTRIC POWER CONSTRUCTION, 2014, 35(8): 1-5.

References

［1］魏文辉,刘文华,滕乐天,等. ±50 Mvar链式STATCOM稳态特性研究［J］. 电力系统自动化,2004,28（03）:28-31，63. ［2］李春华,黄伟雄,袁志昌,等.南方电网±200 Mvar链式STATCOM系统控制策略［J］. 电力系统自动化,2013,37（03）:116-121. ［3］田旭,魏应冬,姜齐荣. 基于模块化结构的电气化铁路统一电能质量控制器［J］. 电力系统自动化，2012,36（15）:101-106. ［4］皮俊波,姜齐荣,魏应冬.一种基于链式结构UPQC的电气化铁路同相供电方案研究［J］.电力设备,2008,9（10）:4-9. ［5］刘钟淇,宋强,刘文华. 基于模块化多电平变流器的轻型直流输电系统［J］. 电力系统自动化，2010，34（2）：53-58. ［6］刘钟淇,宋强,刘文华.采用MMC变流器的VSC-HVDC系统故障态研究［J］. 电力电子技术,2010,44（09）:69-71. ［7］Arthur J K, Manfred W, Peter S. Low output frequency operation of the modular multi-level converter［C］//IEEE Energy Conversion Congress and Exposition，Atlanta,USA,2010:3993-3997. ［8］赵波. 提高静止同步补偿器运行性能的关键技术研究［D］.北京：中国电力科学研究院，2013. ［9］Hagiwara M, Nishimura K, Akagi H. A medium-voltage motor drive with a modular multilevel PWM inverter［J］. IEEE Transaction on Power Electronics，2010，25（7）：1786-1799. ［10］李笑倩，宋强，刘文华，等.采用载波移相调制的模块儿化多电平换流器电容电压平衡控制［J］.中国电机工程学报，2012，32（9）：49-55. ［11］丁冠军，丁明，汤广福，等.新型多电平VSC子模块电容参数与均压策略［J］.中国电机工程学报,2009,29（30）:1-6. ［12］杨晓峰,林智钦,郑琼林,等. 模块组合多电平变换器的研究综述［J］. 中国电机工程学报,2013,33（6）:1-15. ［13］Woodhouse M L，Donoghue M W，Osborne M M. Type testing of the GTO valves for a novel STATCOM convertor［C］//AC-DC Power Transmission Seventh International Conference, 2001: 84-90. ［14］刘文华,宋强,滕乐天,等. 基于链式逆变器的 50MVA 静止同步补偿器的直流电压平衡控制［J］.中国电机工程学报,2004,24（4）:145-150.

[1]	SHEN Baoxing1， LIN Lin1， DONG Qian2， TANG Cong3， JIANG Shouqi2， XIN Yechun2. Coordinated Control Strategy for AC Fault Ride-through of MMC-HVDC Island Power Supply System [J]. Electric Power Construction, 2020, 41(6): 93-99.
[2]	ZHANG Mingqi， LIU Qilin， ZHANG Yingmin. Analysis and Optimization of Factors Influencing Current During MMC Bipolar Fault [J]. Electric Power Construction, 2020, 41(5): 124-132.
[3]	CHEN Ning， QI Lei， CUI Xiang， MA Jiangjiang. Calculation Method for Line-to-Ground Short-Circuit Currents of VSC-HVDC Grid [J]. Electric Power Construction, 2019, 40(4): 119-127.
[4]	FAN Qiang， LU Feng， ZHANG Fan， LI Yu， ZHAO Chengyong， XU Jianzhong. A Method of Determining the Second Order Component of Arm Current to Reduce the Sub-module Capacitance for Modular Multilevel Converters [J]. Electric Power Construction, 2019, 40(2): 87-93.
[5]	WU Chengjie, FU Chao, FAN Shixiong. Control Strategy of Low Voltage Ride Through for Grid-connected PV System Based on Modular Multilevel Converter [J]. Electric Power Construction, 2018, 39(7): 48-56.
[6]	HU Can, FU Chao,WANG Yi. Harmonic Analysis and Modulation Design of MMC in DC Distribution Network [J]. Electric Power Construction, 2018, 39(7): 81-88.
[7]	ZHENG TAO，ZHANG Zihang. Research on Internal Fault Diagnosis and Countermeasure of Modular Multilevel Converter Based on Half Bridge Sub-modules [J]. Electric Power Construction, 2018, 39(6): 42-.
[8]	HAN Naizheng, JIA Xiufang, XU Jianzhong, ZHAO Chengyong . Control Strategy for On-line Smooth Connection of Passive Modular Multilevel Converter Station via DC/DC Converter into DC Grid [J]. Electric Power Construction, 2018, 39(5): 28-.
[9]	ZHANG Tian, JIANG Bin, GONG Yanfeng . An Improved Voltage Balancing Method for Modular Multilevel Converter [J]. Electric Power Construction, 2018, 39(5): 38-.
[10]	WANG Weiru, XIN Yechun, CONG Jiaqi, YANG Yang, ZHANG Di, SONG Zhenzi. Hybrid Modulation Strategy of Modular Multilevel Converter [J]. Electric Power Construction, 2018, 39(3): 77-.
[11]	ZHU Chengzhi1, WU Haibin2, ZHAO Wenqiang3, YU Xiang3, WANG Ke3, XIAO Jianmin3, LU Yi4 . Collaborative Control Strategy of Mlti-DC System for Offshore Islands [J]. Electric Power Construction, 2018, 39(2): 76-.
[12]	ZHAO Jian, LIU Wei,GUO Chunyi,LU Yi, QIU Peng, XUAN Jiazhuo，LI Jihong. Parameter Optimization Method Based on Simplex Algorithm for LCC-LCC+FBMMC Series Based Hybrid HVDC System [J]. Electric Power Construction, 2018, 39(2): 95-.
[13]	TIAN Yanjun， WEI Shilei， WANG Yi， WANG Hui， CHEN Bo， ZHANG Guohao. Order-reduced Startup Strategy for Boosting and Collecting of Photovoltaic System [J]. Electric Power Construction, 2018, 39(11): 77-84.
[14]	LU Yi, LI Jihong, QIU Peng, XIAO Huangqing, LIU Gaoren, XU Zheng. Analysis and Comparison of DC Fault Handling Strategies for Hybrid HVDC System [J]. Electric Power Construction, 2017, 38(8): 33-.
[15]	DONG Hui,SONG Pinggang, ZHOU Zhenbang. Compensation Droop Control of MMC-MTDC Considering Line Voltage Drop [J]. Electric Power Construction, 2017, 38(8): 80-.