三相级联型光伏并网逆变器漏电流抑制研究
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摘要
针对级联型光伏并网逆变器,首先建立了传统三相级联H4光伏并网逆变器拓扑的系统共模模型,分析了系统漏电流、系统共模电压、差模电压三者之间的关系,揭示了传统三相级联H4光伏并网逆变器无法抑制漏电流的原因。提出了一种新型三相级联H5光伏并网逆变器拓扑及其调制策略,有效地抑制了系统漏电流。最后,与三相级联H4光伏并网逆变器拓扑进行了性能对比研究,结果验证了所提方案的有效性。
Three-phase cascaded three-level PV grid-connected inverter was investigated in this paper. The common mode model of the conventional three-phase cascaded H4 grid-connected inverter topology was established. The relationship among the leakage current, common mode voltage and differential mode voltage was analyzed. The inherent reason that the conventional cascaded H4 grid-connected inverter topology failed to reduce the leakage current was clarified. A new three-phase cascaded H5 grid-connected inverter topology and its modulation strategy were proposed. It was able to significantly reduce the leakage current. Finally, the performance tests of the cascaded H4 and H5 grid-connected inverter topologies were carried out. The results verified the effectiveness of the proposed solution.
Three-phase cascaded three-level PV grid-connected inverter was investigated in this paper. The common mode model of the conventional three-phase cascaded H4 grid-connected inverter topology was established. The relationship among the leakage current, common mode voltage and differential mode voltage was analyzed. The inherent reason that the conventional cascaded H4 grid-connected inverter topology failed to reduce the leakage current was clarified. A new three-phase cascaded H5 grid-connected inverter topology and its modulation strategy were proposed. It was able to significantly reduce the leakage current. Finally, the performance tests of the cascaded H4 and H5 grid-connected inverter topologies were carried out. The results verified the effectiveness of the proposed solution.
引文
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[19]Selvamuthukumaran R,Gargand A,Gupta R.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.
[20]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.
[21]Veeranna S B,Beig A R,Yaragatti U R.Performance analysis of PWM strategies for cascaded H-bridge three-level inverter[C]//Proceedings of IEEE Conference on GCC Conference and Exhibition,Dubai,The United Arab Emirates,2011:81-84.
[2]Hernandez J C,Vidal P G,Medina A.Characterization of the insulation and leakage currents of PV generators:Relevance for human safety[J].Renewable Energy,2010,35(3):593-601.
[3]Li Wuhua,Gu Yunjie,Luo Haoze,et al.Topology review and derivation methodology of single-phase transformerless photovoltaic inverters for leakage current suppression[J].IEEE Transactions on Industrial Electronics,2015,62(7):4537-4551.
[4]Gu Y J,Li W H,Zhao Y,et al.Transformerless inverter with virtual DC bus concept for cost-effective grid-connected PV power systems[J].IEEE Transactions on Power Electronics,2013,28(2):793-805.
[5]Zhang L,Sun K,Feng L,et al.A family of neutral point clamped full bridge topologies for transformerless photovoltaic grid tied inverters[J].IEEE Transactions on Power Electronics,2013,28(2):730-739.
[6]Yang B,Li W H,Gu Y J,et al.Improved transformerless inverter with common-mode leakage current elimination for a photovoltaic grid-connected power system[J].IEEETransactions on Power Electronics,2012,27(2):752-762.
[7]Shen J M,Jou H L,Wu J C.Novel transformerless grid-connected power converter with negative grounding for photovoltaic generation system[J].IEEE Transactions on Power Electronics,2012,27(4):1818-1829.
[8]Xiao H,Liu X,Lan K.Zero-voltage-transition full-bridge topologies for transformerless photovoltaic grid-connected inverter[J].IEEE Transactions on Industrial Electronics,2014,61(10):5393-5401.
[9]Breazeale L,Ayyanar R.A photovoltaic array transformerless inverter with film capacitors and silicon carbide transistors[J].IEEE Transactions on Power Electronics,2015,30(3):1297-1305.
[10]Islam M,Mekhilef S.H6-type transformerless single-phase inverter for grid-tied photovoltaic system[J].IET Power Electronics,2015,8(4):636-644.
[11]张犁,孙凯,冯兰兰,等.一种低漏电流六开关非隔离全桥光伏并网逆变器[J].中国电机工程学报,2012,32(15):1-7.Zhang Li,Sun Kai,Feng Lanlan,et al.H6 non-isolated full bridge grid-connected PV inverters with low leakage currents[J].Proceedings of the CSEE,2012,32(15):1-7(in Chinese).
[12]洪峰,刘周成,万运强,等.无漏电流高效可靠三电平双Buck并网逆变器[J].中国电机工程学报,2014,34(9):1327-1336.Hong Feng,Liu Zhoucheng,Wan Yunqiang,et al.High-efficiency high-reliability dual buck three-level grid-connected inverters without leakage currents[J].Proceedings of the CSEE,2014,34(9):1327-1336(in Chinese).
[13]张兴,邵章平,王付胜,等.非隔离型三相三电平光伏逆变器的共模电流抑制[J].中国电机工程学报,2013,33(3):29-36.Zhang Xing,Shao Zhangping,Wang Fusheng,et al.Leakage current reduction for transformerless three phase three-level photovoltaic inverters[J].Proceedings of the CSEE,2013,33(3):29-36(in Chinese).
[14]Busquets-Monge S,Rocabert J,Rodriguez P,et al.Multilevel diode-clamped converter for photovoltaic generators with independent voltage control of each solar array[J].IEEE Transactions on Industrial Electronics,2008,55(7):2713-2723.
[15]Rodriguez J,Franquelo L G,Kouro S,et al.Multilevel converters:An enabling technology for high-power applications[J].Proceedings of IEEE,2009,97(11):1786-1817.
[16]叶满园,周琪琦,蔡鸿,等.基于捕食策略遗传算法的3电平中点箝位型逆变器特定谐波消除脉宽调制技术[J].高电压技术,2014,40(11):3569-3576.Ye Manyuan,Zhou Qiqi,Cai Hong,et al.SHEPWMtechnique applied to tri-level neutral pointed clamped inverter based on predation strategies[J].High Voltage Engineering,2014,40(11):3569-3576(in Chinese).
[17]Malinowski M,Gopakumar K,Rodriguez J,et al.Asurvey on cascaded multilevel inverters[J].IEEETransactions on Industrial Electronics,2010,57(7):2197-2206.
[18]李继华,阮新波,王学华.级联型多电平逆变器线电压谐波优化的SVPWM策略[J].电工技术学报,2014,29(6):120-128.Li Jihua,Ruan Xinbo,Wang Xuehua.A SVPWM strategy with optimal line-to-line voltage harmonic spectrum for cascaded multilevel inverters[J].Transactions of China Electrotechnical Society,2014,29(6):120-128(in Chinese).
[19]Selvamuthukumaran R,Gargand A,Gupta R.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.
[20]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.
[21]Veeranna S B,Beig A R,Yaragatti U R.Performance analysis of PWM strategies for cascaded H-bridge three-level inverter[C]//Proceedings of IEEE Conference on GCC Conference and Exhibition,Dubai,The United Arab Emirates,2011:81-84.