非隔离型光伏并网逆变器软开关技术
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摘要
非隔离型光伏并网逆变器的电路拓扑技术和市场应用得到了充分发展和广泛普及。该文讨论非隔离型光伏并网逆变器的软开关实现技术的可行性和实现方法,为下一代高功率密度非隔离型光伏并网逆变器打下基础。为此,该文提出一种兼顾直流母线极性和独立零矢量续流结构的并联型双谐振网络的软开关实现架构,取名为"续流谐振腔逆变器"。在新型软开关架构的指引下分别以零电压和零电流两种软开关实现为目标,通过谐振轨迹规划、基本谐振单元和拓扑改造优化等步骤,完成当前市场主流非隔离型光伏并网逆变器拓扑的软开关化升级。同时,讨论了软开关非隔离型光伏并网逆变器的漏电流和非单位功率因数运行等关键技术问题,并给出建议的解决措施。进而挑选ZVT-Heric和ZCT-Heric为例搭建了3kW功率等级实验样机,进行了原理验证。最后总结分析了软开关非隔离型光伏并网逆变器的技术特点和面临的挑战。
Nowadays, the topology techniques and market share of transformerless PV grid-connected inverters(TLI) have been dramatically developed and grown, respectively. In order for the development of next generation TLIs with high power density, this paper was focus on the feasibility and realization of soft-switching TLIs. In doing so, a parallel soft-switching configuration with DC bus polarities feature and independent zero-vector freewheeling branch named as freewheeling-resonance-tank inverter has been proposed first. Based on this new soft-switching configuration, the soft-switching goal of TLIs from two ways of zero-voltage switching and zero-current switching, respectively, has been realized by planning resonance trajectories, building basic resonance cells, and upgrading and optimizing circuit topologies, step by step. Meanwhile, leakage current and non-unity power factor problems have been discussed, and some solutions have also been mentioned. Furthermore, by taking ZVT-Heric and ZCT-Heric as examples, respectively, two 3 kW prototypes have been built in our lib to prove the effectiveness of proposed thought and operation principles. Finally, the performance characteristics of soft-switching TLIs have been concluded and some challenges still faced have also been revealed.
Nowadays, the topology techniques and market share of transformerless PV grid-connected inverters(TLI) have been dramatically developed and grown, respectively. In order for the development of next generation TLIs with high power density, this paper was focus on the feasibility and realization of soft-switching TLIs. In doing so, a parallel soft-switching configuration with DC bus polarities feature and independent zero-vector freewheeling branch named as freewheeling-resonance-tank inverter has been proposed first. Based on this new soft-switching configuration, the soft-switching goal of TLIs from two ways of zero-voltage switching and zero-current switching, respectively, has been realized by planning resonance trajectories, building basic resonance cells, and upgrading and optimizing circuit topologies, step by step. Meanwhile, leakage current and non-unity power factor problems have been discussed, and some solutions have also been mentioned. Furthermore, by taking ZVT-Heric and ZCT-Heric as examples, respectively, two 3 kW prototypes have been built in our lib to prove the effectiveness of proposed thought and operation principles. Finally, the performance characteristics of soft-switching TLIs have been concluded and some challenges still faced have also been revealed.
引文
[1]Tang Yi,Yao Wenli,Poh L B,et al.Highly reliable transformerless photovoltaic inverters with leakage current and pulsating power elimination[J].IEEETransactions on Industrial Electronics,2016,63(2):1016-1026.
[2]Li W,Gu Y,Luo H,et al.Topology review and derivation methodology of single-phase transformerless photovoltaic inverters for leakage current suppression[J].IEEETransactions on Industrial Electronics,2015,62(7):4537-4551.
[3]Guo X,Jia X.Hardware-based cascaded topology and modulation strategy with leakage current reduction for transformerless PV systems[J].IEEE Transactions on Industrial Electronics,2016,62(12):7823-7832.
[4]Xiao H,Lan K,Zhang L.An improved zero-current-switching single-phase transformerless PVH6 inverter with switching loss-free[J].IEEE Transactions on Industrial Electronics,2017,64(10):7896-7905.
[5]Xiao H,Lan K,Zhang L.A zero-voltage-transition HERIC-type transformerless photovoltaic grid-connected inverter[J].IEEE Transactions on Industrial Electronics,2017,64(2):1222-1232.
[6]Xiao H,Lan K,Zhou B,et al.A family of zero-current-transition transformerless photovoltaic grid-connected inverter[J].IEEE Trans.on Power Electronics,2015,30(6):3156-3165.
[7]Xiao H,Liu X,Lan K.Zero-voltage-transition full bridge topologies for transformerless photovoltaic grid-connected inverter[J].IEEE Trans.on Industrial Electronics,2014,61(10):5393-5401.
[8]曾正,邵伟华,胡博容,等.Si C器件在光伏逆变器中的应用与挑战[J].中国电机工程学报,2017,37(1):221-232.Zeng Zheng,Shao Weihua,Hu Borong,et al.Chances and challenges of photovoltaic inverters with silicon carbide devices[J].Proceedings of the CSEE,2017,37(1):221-232(in Chinese).
[9]孙凯,陈彤,张瑜洁.碳化硅光伏逆变器发展现状[J].新材料产业,2014(9):34-38.Sun Kai,Chen Tong,Zhang Yujie.Development status of SiC photovoltaic inverters[J].Advanced Materials Industry,2014(9):34-38(in Chinese).
[10]Saridakis S,Koutroulis E,Blaabjerg F.Optimization of SiC-based H5 and conergy-NPC transformerless PVinverters[C]//IEEE Energy Conversion Congress and Exposition.Denver,CO,USA:IEEE,2013:4732-4739.
[11]Divan D.The resonant DC link converter-a new concept in static power conversion[J].IEEE Trans.on Industrial Electronics,1989,25(2):317-325.
[12]Divan D,Skibinski G.Zero-switching-loss inverters for high-power applications[J].IEEE Trans.on Industrial Applications,1989,25(4):634-643.
[13]Bellar M,Wu T,Tchamdjou A,et al.A review of soft-switched DC-AC converters[J].IEEE Trans.on Industrial Applications,1998,34(4):847-860.
[14]Jung Y,Yu G,Choi J,et al.High-frequency DC link inverter for grid-connected photovoltaic system[C]//Conference Record of the Twenty-Ninth IEEEPhotovoltaic Specialists Conference.LA,USA:IEEE,2002:1410-1413.
[15]Kim Y,Kim J,Ji Y,et al.Photovoltaic parallel resonant DC-link soft switching inverter using hysteresis current control[C]//Applied Power Electronics Conference&Exposition,2010:2275-2280.
[16]胡光铖.Si C单相光伏逆变器效率分析[D].杭州:浙江大学,2014.Hu Guangcheng.Efficiency analysis of single-phase photovoltaic inverter[D].Hangzhou:Zhejiang University,2014(in Chinese).
[17]陈厚岩,王环,许洪华.具有零电流关断特性的并网型光伏逆变器研制[J].电力电子技术,2005,39(3):38-39.Chen Houyan,Wang Huan,Xu Honghua.Development of photovoltaic grid-connected inverters with zero-current turn-off characteristics[J].Power Electronics,2005,39(3):38-39(in Chinese).
[18]吕丹.光伏并网逆变器软开关技术研究[D].北京:北京交通大学,2012.LüDan.Research on soft-switching techniques of photovoltaic grid-connected inverter[D].Beijing:Beijing Jiaotong University,2012(in Chinese).
[19]Gupta V,Khajehoddin S A,Jain P.Phase-staggered multiple ZVS inverters for grid-connected PVsystems[C]//2013 IEEE Energy Conversion Congress and Exposition.Denver,CO,USA:IEEE,2013:4503-4510.
[20]Chen B,Lai J,Chen C,et al.Design and optimization of99%CEC efficiency soft-switching photovoltaic inverter[C]//2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition(APEC).Long Beach,CA,USA:IEEE,2013:946-951.
[21]肖华锋,谢少军,贡力,等.非隔离型光伏并网逆变器漏电流分析模型研究[J].中国电机工程学报,2010,30(18):9-14.Xiao Huafeng,Xie Shaojun,Gong Li,et al.Study on leakage current model for tansformerless photovoltaic grid-connected inverter[J].Proceedings of The CSEE,2010,30(18):9-14(in Chinese).
[22]肖华锋,杨晨,谢少军.基于改进型全桥电路的非隔离光伏并网逆变器[J].中国电机工程学报,2011,31(3):40-46.Xiao Huafeng,Yang Chen,Xie Shaojun.Atransformerless PV grid-connected inverter based on improved full bridge topology[J].Proceedings of The CSEE,2011,31(3):40-46(in Chinese).
[23]Xiao H,Lan K,Zhang L.A quasi-unipolar SPWMfull-bridge transformerless PV grid-connected inverter with constant common-mode voltage[J].IEEE Trans.on Power Electronics,2015,30(6):3122-3132.
[24]Schmidt H,Siedle C,Ketterer J.Wechselrichter zum umwandeln einer elektrischen gleichspannung in einen wechselstrom oder eine wechselspannung:EP Patent EP 1369 985 A2[P].2003-05-15.
[25]Victor M,Greizer F,Bremicker S,et al.Method of converting a direct current voltage from a source of direct current voltage,more specifically from a photovoltaic source of direct current voltage,into a alternating current voltage:U.S.Patent US 20050286281 A1[P].2005-12-29.
[26]Gonz′alez R,Lopez J,Sanchis P,et al.Transformerless inverter for single-phase photovoltaic systems[J].IEEETrans.on Power Electronics,2007,22(2):693-697.
[27]Yu Wensong,Lai J S,Qian H,et al.High-efficiency MOSFET inverter with H6-type configuration for photovoltaic nonisolated AC-module applications[J].IEEE Trans.on Power Electronics,2011,26(4):1253-1260.
[2]Li W,Gu Y,Luo H,et al.Topology review and derivation methodology of single-phase transformerless photovoltaic inverters for leakage current suppression[J].IEEETransactions on Industrial Electronics,2015,62(7):4537-4551.
[3]Guo X,Jia X.Hardware-based cascaded topology and modulation strategy with leakage current reduction for transformerless PV systems[J].IEEE Transactions on Industrial Electronics,2016,62(12):7823-7832.
[4]Xiao H,Lan K,Zhang L.An improved zero-current-switching single-phase transformerless PVH6 inverter with switching loss-free[J].IEEE Transactions on Industrial Electronics,2017,64(10):7896-7905.
[5]Xiao H,Lan K,Zhang L.A zero-voltage-transition HERIC-type transformerless photovoltaic grid-connected inverter[J].IEEE Transactions on Industrial Electronics,2017,64(2):1222-1232.
[6]Xiao H,Lan K,Zhou B,et al.A family of zero-current-transition transformerless photovoltaic grid-connected inverter[J].IEEE Trans.on Power Electronics,2015,30(6):3156-3165.
[7]Xiao H,Liu X,Lan K.Zero-voltage-transition full bridge topologies for transformerless photovoltaic grid-connected inverter[J].IEEE Trans.on Industrial Electronics,2014,61(10):5393-5401.
[8]曾正,邵伟华,胡博容,等.Si C器件在光伏逆变器中的应用与挑战[J].中国电机工程学报,2017,37(1):221-232.Zeng Zheng,Shao Weihua,Hu Borong,et al.Chances and challenges of photovoltaic inverters with silicon carbide devices[J].Proceedings of the CSEE,2017,37(1):221-232(in Chinese).
[9]孙凯,陈彤,张瑜洁.碳化硅光伏逆变器发展现状[J].新材料产业,2014(9):34-38.Sun Kai,Chen Tong,Zhang Yujie.Development status of SiC photovoltaic inverters[J].Advanced Materials Industry,2014(9):34-38(in Chinese).
[10]Saridakis S,Koutroulis E,Blaabjerg F.Optimization of SiC-based H5 and conergy-NPC transformerless PVinverters[C]//IEEE Energy Conversion Congress and Exposition.Denver,CO,USA:IEEE,2013:4732-4739.
[11]Divan D.The resonant DC link converter-a new concept in static power conversion[J].IEEE Trans.on Industrial Electronics,1989,25(2):317-325.
[12]Divan D,Skibinski G.Zero-switching-loss inverters for high-power applications[J].IEEE Trans.on Industrial Applications,1989,25(4):634-643.
[13]Bellar M,Wu T,Tchamdjou A,et al.A review of soft-switched DC-AC converters[J].IEEE Trans.on Industrial Applications,1998,34(4):847-860.
[14]Jung Y,Yu G,Choi J,et al.High-frequency DC link inverter for grid-connected photovoltaic system[C]//Conference Record of the Twenty-Ninth IEEEPhotovoltaic Specialists Conference.LA,USA:IEEE,2002:1410-1413.
[15]Kim Y,Kim J,Ji Y,et al.Photovoltaic parallel resonant DC-link soft switching inverter using hysteresis current control[C]//Applied Power Electronics Conference&Exposition,2010:2275-2280.
[16]胡光铖.Si C单相光伏逆变器效率分析[D].杭州:浙江大学,2014.Hu Guangcheng.Efficiency analysis of single-phase photovoltaic inverter[D].Hangzhou:Zhejiang University,2014(in Chinese).
[17]陈厚岩,王环,许洪华.具有零电流关断特性的并网型光伏逆变器研制[J].电力电子技术,2005,39(3):38-39.Chen Houyan,Wang Huan,Xu Honghua.Development of photovoltaic grid-connected inverters with zero-current turn-off characteristics[J].Power Electronics,2005,39(3):38-39(in Chinese).
[18]吕丹.光伏并网逆变器软开关技术研究[D].北京:北京交通大学,2012.LüDan.Research on soft-switching techniques of photovoltaic grid-connected inverter[D].Beijing:Beijing Jiaotong University,2012(in Chinese).
[19]Gupta V,Khajehoddin S A,Jain P.Phase-staggered multiple ZVS inverters for grid-connected PVsystems[C]//2013 IEEE Energy Conversion Congress and Exposition.Denver,CO,USA:IEEE,2013:4503-4510.
[20]Chen B,Lai J,Chen C,et al.Design and optimization of99%CEC efficiency soft-switching photovoltaic inverter[C]//2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition(APEC).Long Beach,CA,USA:IEEE,2013:946-951.
[21]肖华锋,谢少军,贡力,等.非隔离型光伏并网逆变器漏电流分析模型研究[J].中国电机工程学报,2010,30(18):9-14.Xiao Huafeng,Xie Shaojun,Gong Li,et al.Study on leakage current model for tansformerless photovoltaic grid-connected inverter[J].Proceedings of The CSEE,2010,30(18):9-14(in Chinese).
[22]肖华锋,杨晨,谢少军.基于改进型全桥电路的非隔离光伏并网逆变器[J].中国电机工程学报,2011,31(3):40-46.Xiao Huafeng,Yang Chen,Xie Shaojun.Atransformerless PV grid-connected inverter based on improved full bridge topology[J].Proceedings of The CSEE,2011,31(3):40-46(in Chinese).
[23]Xiao H,Lan K,Zhang L.A quasi-unipolar SPWMfull-bridge transformerless PV grid-connected inverter with constant common-mode voltage[J].IEEE Trans.on Power Electronics,2015,30(6):3122-3132.
[24]Schmidt H,Siedle C,Ketterer J.Wechselrichter zum umwandeln einer elektrischen gleichspannung in einen wechselstrom oder eine wechselspannung:EP Patent EP 1369 985 A2[P].2003-05-15.
[25]Victor M,Greizer F,Bremicker S,et al.Method of converting a direct current voltage from a source of direct current voltage,more specifically from a photovoltaic source of direct current voltage,into a alternating current voltage:U.S.Patent US 20050286281 A1[P].2005-12-29.
[26]Gonz′alez R,Lopez J,Sanchis P,et al.Transformerless inverter for single-phase photovoltaic systems[J].IEEETrans.on Power Electronics,2007,22(2):693-697.
[27]Yu Wensong,Lai J S,Qian H,et al.High-efficiency MOSFET inverter with H6-type configuration for photovoltaic nonisolated AC-module applications[J].IEEE Trans.on Power Electronics,2011,26(4):1253-1260.