Abstract：Aimed at the leakage current issue of the transformerless cascaded H-bridge inverter, this paper first establishes the equivalent common-mode circuit of the inverter with the parasitic capacitance, and analyzes the characteristics of leakage current in the symmetrical and asymmetrical inductance circuit respectively. The analysis shows that the leakage current can be eliminated through optimizing the modulation methods in the symmetrical circuit, but in the asymmetrical circuit the leakage current issue cannot be solved through modulation strategies. For this reason a new modulation strategy for the symmetrical circuit based on the multicarrier pulse width modulation is proposed which can eliminate the leakage current effectively with simple implementation. Finally, the validity and effectiveness of the proposed method is verified by the simulation and experiment.
王付胜, 于世能. 级联H桥逆变器漏电流分析与抑制[J]. 电工技术学报, 2017, 32(增刊2): 103-110.
Wang Fusheng, Yu Shineng. Analysis and Suppression of the Leakage Currents in the Cascaded H-Bridge Inverter. Transactions of China Electrotechnical Society, 2017, 32(增刊2): 103-110.
[1] Tolbert L M , Peng F Z. Multilevel converters as a utility interface for renewable energy systems[C]// Power Engineering Society Summer Meeting, Seattle, WA, 2000: 1271-1274. [2] Sastry J, Bakas P, Kim H, et al. Evaluation of cascaded H-bridge inverter for utility-scale photovoltaic systems [J]. Renewable Energy, 2014, 69(69): 208-218. [3] Malinowski M, Gopakumar K, Rodriguez J, et al. A survey on cascaded multilevel inverters[J]. IEEE Transactions on Industrial Electronics, 2010, 57(7): 2197-2206. [4] 奥普蒂斯汀技术公司. DC-AC 转换方法: 中国, 201480010635.8[P]. 2014-02-24. [5] Gubia E, Sanchis P, Ursua A, et al. Ground current in single-phase transformerless photovoltaic systems[J]. Progress in Photovoltaics Research & Applications, 2007, 15(7): 629-650. [6] Xiao Huafeng, Xie Shaojun. Leakage current analy- tical model and application in single-phase trans- formerless photovoltaic grid-connected inverter[J]. IEEE Transactions on Power Electronics, 2010, 52(4): 902-913. [7] 胡存刚, 姚培, 张云雷, 等. 高效非隔离单相并网MOSFET逆变器拓扑及控制策略[J]. 中国电工技术学报, 2016, 31(13): 82-91. Hu Cungang, Yao Pei, Zhang Yunlei, et al. Topology and control strategy for high efficient non-isolated single-phase grid-connected MOSFET inverter[J]. Transactions of China Electrotechnical Society, 2016, 31(13): 82-91. [8] 杨晓光, 姜龙斌, 冯俊博, 等. 一种新型高效无变压器型单相光伏逆变器[J]. 电工技术学报, 2015, 30(8): 97-103. Yang Xiaoguang, Jiang Longbin, Feng Junbo, et al. A new high efficiency transformerless single-phase photovoltaic inverters[J]. Transactions of China Elec- trotechnical Society, 2013, 30(8): 97-103. [9] 朱克平, 江道灼. 一种改进型的光伏并网逆变器[J]. 电力系统保护与控制, 2013, 41(6): 99-104. Zhu Keping, Jiang Daozhuo. An improved inverter for a grid-connected photovoltaic power system[J]. Power System Protection and Control, 2013, 41(6): 99-104. [10] 邬伟扬, 郭小强. 无变压器非隔离型光伏并网逆变器漏电流抑制技术[J]. 中国电机工程学报, 2012, 32(18): 1-8. Wu Weiyang, Guo Xiaoqiang. A review of novel leakage current suppression techniques for trans- formerless photovoltaic inverters[J]. Proceedings of the CSEE, 2012, 32(18): 1-8. [11] Li W, Gu Y, Luo H, et al. Topology review and derivation methodology of single phase transfor- merless photovoltaic inverters for leakage current suppression[J]. IEEE Transactions on Industrial Electro- nics, 2015, 62(7): 4537-4551. [12] Lopez O, Freijedo F D, Yepes A G, et al. Eliminating ground current in a transformerless photovoltaic app- lication[J]. IEEE Transactions on Energy Conversion, 2010, 25(1): 140-147. [13] Ji Baojian, Wang Jianhua, Zhao Jianfeng. High- efficiency single-phase transformerless PV H6 inverter with hybrid modulation method[J]. IEEE Transac- tions on Industrial Electronics, 2013, 60(5): 2104- 2115. [14] Zhou Y, Li H. Analysis and suppression of leakage current in cascaded-multilevel-inverter based PV systems[J]. IEEE Transactions on Power Electronics, 2014, 29(10): 5265-5277. [15] 郭小强, 魏宝泽, 贾晓瑜, 等. FB10三相非隔离光伏并网逆变器共模电流抑制研究[J]. 电工技术学报, 2015, 30(8): 135-142. Guo Xiaoqiang, Wei Baoze, Jia Xiaoyu, et al. Common mode current suppression for FB10 three- phase non-isolated PV grid-connected inverter[J]. Transactions of China Electrotechnical Society, 2015, 30(8): 135-142. [16] Rajasekar Selvamuthukumaran, Abhishek Garg, Rajesh Gupta. Hybrid multicarrier modulation to reduce leakage current in a transformerless cascaded multilevel inverter for photovoltaic systems[J]. IEEE Transactions on Power Electronics, 2015, 30(4): 1779-1783. [17] Tamas Kerekes,Remus Teodorescu,Marco Liserre,et al. Evaluation of three-phase transformerless photo- voltaic inverter topologies[J]. IEEE Transactions on Power Electronics, 2009, 24(9): 2202-2211. [18] 孙宜峰, 阮新波. 级联多电平逆变器的功率均衡策略[J]. 中国电机工程学报, 2006, 26(4): 126-133. Sun Yifeng, Ruan Xinbo. Power balance control schemes for cascaded multilevel inverters[J]. Procee- dings of the CSEE, 2006, 26(4): 126-133.
2017, Vol. 32 
