Abstract：Modular multilevel converter (MMC) is widely used in the field of high power and high voltage energy conversion. Especially in high voltage direct current (HVDC) transmission system, there are hundreds of submodules (SMs) in each arm, and a large number of sensors need to be installed to measure the capacitor voltages of all SMs. Then the switching signals are allocated for SMs by means of modulation strategy. The use of a large number of sensors increases the complexity and costs of the measurement system. Therefore, in this paper, a balance control strategy with single sensor measurement based nearest level modulation (NLM) for capacitor voltages is proposed. Different from the conventional measurement with individual voltage sensor for each SM, the proposed strategy employs only one voltage sensor for each arm to measure arm voltage. Combining the measured arm voltage and the charging/discharging direction of the arm current, the capacitor voltage can be obtained through prediction-modification operation in real time to realize the capacitor voltages balance control. Simultaneously, the influence of modulation ratio and control frequency on the prediction-modification balance control strategy can be further qualitatively analyzed, which can provide evidence for selecting proper control parameters. Simulation and experimental results validate the correctness and stability of the proposed strategy under transient and steady-state conditions.
岳雨霏, 徐千鸣, 罗安, 郭鹏. 模块化多电平换流器单传感器电容电压平衡控制策略[J]. 电工技术学报, 2018, 33(16): 3663-3676.
Yue Yufei, Xu Qianming, Luo An, Guo Peng. Capacitor Voltages Balancing Control Strategy with Single Sensor Measurement for Modular Multilevel Converter. Transactions of China Electrotechnical Society, 2018, 33(16): 3663-3676.
[1] Debnath S, Qin J, Bahrani B, et al.Operation, control, and applications of the modular multilevel converter: a review[J]. IEEE Transactions on Power Electronics, 2015, 30(1): 37-53. [2] 徐殿国, 李彬彬, 周少泽. 模块化多电平高压变频技术研究综述[J]. 电工技术学报, 2017, 32(20): 104-116. Xu Dianguo, Li Binbin, Zhou Shaoze.Overview of the modular multilevel converter based high voltage motor drive[J]. Transactions of China Electro- technical Society, 2017, 32(20): 104-116. [3] 阎发友, 汤广福, 贺之渊, 等. 基于MMC的直流电网分层能量平衡控制[J]. 中国电机工程学报, 2016, 36(21): 5757-5765. Yan Fayou, Tang Guangfu, He Zhiyuan, et al.Hierarchical energy balance control for MMC-based DC grid[J]. Proceedings of the CSEE, 2016, 36(21): 5757-5765. [4] 李凯, 赵争鸣, 袁立强, 等. 基于能量平衡的降低模块化多电平变换器子模块电容电压波动控制策略[J]. 电工技术学报, 2017, 32(14): 17-26. Li Kai, Zhao Zhengming, Yuan Liqiang, et al.Control strategy based on the energy balance sub-module capacitor voltage fluctuation of modular multilevel converter[J]. Transactions of China Electrotechnical Society, 2017, 32(14): 17-26. [5] 张静, 郝亮亮, 黄银华, 等. 基于叠加逼近调制的模块化多电平换流器谐波环流抑制策略[J]. 电网技术, 2017, 41(11): 3539-3546. Zhang Jing, Hao Liangliang, Huang Yinhua, et al.Circulating harmonic suppression strategy for MMC based on superimposed approach modulation[J]. Power System Technology, 2017, 41(11): 3539-3546. [6] 黄守道, 彭也伦, 廖武. 模块化多电平型变流器电容电压波动及其抑制策略研究[J]. 电工技术学报, 2015, 30(7): 62-71. Huang Shoudao, Peng Yelun, Liao Wu.Study of capacitor voltage fluctuation and its suppression for modular multilevel converter[J]. Transactions of China Electrotechnical Society, 2015, 30(7): 62-71. [7] 徐千鸣, 罗安, 马伏军, 等. 谐振滤波型模块化多电平换流器低频控制方法[J]. 中国电机工程学报, 2016, 36(2): 489-498. Xu Qianming, Luo An, Ma Fujun, et al.The control scheme of modular multilevel converter with tuned filter operating at low frequency[J]. Proceedings of the CSEE, 2016, 36(2): 489-498. [8] 刘国伟, 姜齐荣, 魏应东. 低频率工况下模块化多电平变流器电容电压平衡控制策略[J]. 电工技术学报, 2014, 29(8): 166-172. Liu Guowei, Jiang Qirong, Wei Yingdong, et al.Study on capacitor voltage balancing control of modular multilevel converters at low frequency[J]. Transactions of China Electrotechnical Society, 2014, 29(8): 166-172. [9] 辛业春, 王朝斌, 李国庆, 等. 模块化多电平换流器子模块电容电压平衡改进控制方法[J]. 电网技术, 2014, 38(5): 1291-1296. Xin Yechun, Wang Chaobin, Li Guoqing, et al.An improved balance control for sub-module capacitor voltage of modular multilevel converter[J]. Power System Technology, 2014, 38(5): 1291-1296. [10] Nademi H, Das A, Norum L E.Modular multilevel converter with an adaptive observer of capacitor voltages[J]. IEEE Transactions on Power Electronics, 2015, 30(1): 235-248. [11] Ghazanfari A, Mohamed A R I. A hierarchical permutation cyclic coding strategy for sensorless capacitor voltage balancing in modular multilevel converters[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2016, 4(2): 576-588. [12] Ahmed K H, Adam G P.New modified staircase modulation and capacitor balancing strategy of 21-level modular multilevel converter for HVDC transmission systems[C]//7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014), Manchester, UK, 2014: 1-6. [13] Osama Abushafa, Shady Gadoue, Mohamed Dhaidah, et al.Capacitor voltage estimation in modular multilevel converters using a Kalman filter algorithm[C]// IEEE International Conference on Industrial Technology (ICIT), Seville, Spain, 2015: 3016-3021. [14] Ricard Picas, Jordi Zaragoza, Josep Pou, et al.New measuring technique for reducing the number of voltage sensors in modular multilevel converters[J]. IEEE Transactions on Power Electronics, 2016, 31(1): 177-187. [15] Rong F, Gong X, Li X, et al.A new voltage measure method for MMC based on sample delay compensation[J]. IEEE Transactions on Power Electronics, 2017. [16] Deng F, Chen Z.A control method for voltage balancing in modular multilevel converters[J]. IEEE Transactions on Power Electronics, 2014, 29(1): 66-76. [17] 郭高朋, 姚良忠, 温家良. 模块化多电平换流器子模块分组调制及均压控制[J]. 中国电机工程学报, 2016, 36(1): 145-153. Guo Gaopeng, Yao Liangzhong, Wen Jialiang.The group modulation and voltage balance control of the sub-modules in modular multilevel converter[J]. Proceedings of the CSEE, 2016, 36(1): 145-153. [18] 崔福博, 郭剑波, 荆平, 等. 新型多电平电压源型换流器模块的拓扑机制与调制策略[J]. 电网技术, 2014, 38(7): 1939-1945. Cui Fubo, Guo Jianbo, Jing Ping, et al.A balance control strategy for bridge arm capacitor voltage for MMC based UPFC[J]. Power System Technology, 2014, 38(7): 1939-1945. [19] 屠卿瑞, 徐政, 郑翔, 等. 一种优化的模块化多电平换流器电压均衡控制方法[J]. 电工技术学报, 2011, 26(5): 15-20. Tu Qingrui, Xu Zheng, Zheng Xiang, et al.An optimized voltage balancing method for modular multilevel converter[J]. Transactions of China Electrotechnical Society,2011, 26(5): 15-20.
2018, Vol. 33 
