混合模块化直流固态变压器I:工作原理及稳态特性分析
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摘要
作为柔性直流配网的关键设备,直流固态变压器(DCSST)的控制性能和效率对提高系统实用性和经济性具有重要意义。不同于现有的模块化级联型DCSST,结合移相型双有源桥(PS-DAB)变换器和串联谐振型双有源桥(SR-DAB)变换器,提出一种混合型模块化直流固态变压器(HMDCSST)。该DCSST融合了PS-DAB控制灵活以及SR-DAB运行效率高的优点,较原有的DCSST拓扑,在保持灵活的电压调节能力的同时,可提高功率传输效率,且由于SR-DAB模块运行于开环模式,进而降低了系统设计复杂度。分析HMDCSST的工作原理,给出平均值数学模型以及功率损耗模型,并对该混合模型在定输出电压控制模式下的输入输出特性及功率传输效率进行详细分析。最后,通过实验结果表明,所提出混合模块化直流固态变压器的功率传输效率可达96.4%,较单一PS-DAB型DCSST,可提升约1.0%。此外,输入侧和输出侧扰动实验进一步验证了工作原理及稳态特性分析的正确性。
As the key equipment of flexible dc distribution network, the control performance and conversion efficiency of DC solid-state transformers(DCSST) are significant for improving system practicability and economic efficiency. Unlike the existing DCSST, this paper presents a hybrid modular solid-state transformer(HMDCSST), which combines the phase shift dual active-bridge(PS-DAB) and the series resonant DAB(SR-DAB) in the way that the inputs are in series and the outputs are paralleled. The PS-DAB has the advantage of flexible voltage control while the SR-DAB features high efficiency, both of which can be inherited by the HMDCSST. Thus comparing with the original DCSST, the HMDCSST can improve power efficiency and reduce system design complexity,without sacrificing the flexible controllability. Working principle of the HMDCSST is analyzed, and the average mathematical model and power loss model are derived. Then detailed analysis of the input/output characteristics and power transmission efficiency under constant output voltage control mode are carried out. Finally, the experimental results show that the proposed HMDCSST can achieve a power efficiency of 96.4%, which is 1.0% higher than traditional PS-DAB based DCSST. In addition,experiments under the input and output disturbance further verify the correctness of working principle and steady-state characteristics.
As the key equipment of flexible dc distribution network, the control performance and conversion efficiency of DC solid-state transformers(DCSST) are significant for improving system practicability and economic efficiency. Unlike the existing DCSST, this paper presents a hybrid modular solid-state transformer(HMDCSST), which combines the phase shift dual active-bridge(PS-DAB) and the series resonant DAB(SR-DAB) in the way that the inputs are in series and the outputs are paralleled. The PS-DAB has the advantage of flexible voltage control while the SR-DAB features high efficiency, both of which can be inherited by the HMDCSST. Thus comparing with the original DCSST, the HMDCSST can improve power efficiency and reduce system design complexity,without sacrificing the flexible controllability. Working principle of the HMDCSST is analyzed, and the average mathematical model and power loss model are derived. Then detailed analysis of the input/output characteristics and power transmission efficiency under constant output voltage control mode are carried out. Finally, the experimental results show that the proposed HMDCSST can achieve a power efficiency of 96.4%, which is 1.0% higher than traditional PS-DAB based DCSST. In addition,experiments under the input and output disturbance further verify the correctness of working principle and steady-state characteristics.
引文
[1]Feng Jianhua,Chu Wenqiang,Zhang Zhixue.Power electronic transformer-based railway traction system challengs and opportunities[J].IEEE Journal of Emerging and Selected Topics in Power Electronicss,2017,5(3):1237-1253.
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[9]陈申,吕征宇,姚玮.LLC谐振型软开关直流变压器的研究与实现[J].电工技术学报,2012,27(10):163-169.Chen Shen,LüZhengyu,Yao Wei.Research and verification on LLC resonant soft switching DC-DCtransformer[J].Transactions of China Electrotechnical Society,2012,27(10):163-169.
[10]李建国,赵彪,宋强,等.适用于中压直流配网的多电平直流链固态变压器[J].中国电机工程学报2016,36(14):3717-3725.LI Jianguo,Zhao Biao,Song Qiang,et al.DC solid state transformer based on multilevel DC link for medium-voltage DC distribution application[J].Proceedings of the CSEE,2016,36(14):3717-3725.
[11]Sixifo Falcones.A DC-DC multiport-converter-based solid-state transformer integrating distributed generation and storage[J].IEEE Transactions on Power Electronics,2013,28(5):2192-2203.
[12]Li X,Bhat A.Analysis and design of high-frequency isolated dual-bridge series resonant DC/DC converter[J].IEEE Transactions on Power Electronics2010,25(4):850-862.
[13]王聪,沙广林,王俊,等.基于双重移相控制的双有源桥DC-DC变换器的软开关[J].电工技术学报,2015,30(12):106-113.Wang Cong,Sha Guanglin,Wang Jun,et al.The analysis of zero voltage switching dual active bridge DC-DC converters based on dual-phase-shifting control[J].Transactions of China Electrotechnical Society,2015,30(12):106-113.
[14]程红,高巧梅,朱锦标,等.基于双重移相控制的双向全桥DC-DC变换器动态建模与最小回流功率控制[J].电工技术学报,2014,29(3):245-253.Cheng Hong,Gao Qiaomei,Zhu Jinbiao,et al.Dynamic modeling and minimum backflow power controlling of the bi-directional full-bridge DC-DCconverters based on dual-phase-shifting control[J].Transactions of China Electrotechnical Society,2014,29(3):245-253.
[15]于德,付超,王毅,等.隔离型双向直流变换器的最小回流功率移相控制方法[J].电工技术学报,2017,32(24):126-137.Yu De,Fu Chao,Wang Yi,et al.The phase-shifted control method of isolated bidirectional DC-DCconverter with minimum backflow power[J].Transactions of China Electrotechnical Society,201732(24):126-137.
[16]张勋,王广柱,王婷.双向全桥DC-DC变换器基于电感电流应力的双重移相优化控制[J].电工技术学报,2016,31(22):100-106.Zhang Xun,Wang Guangzhu,Wang Ting.Optimized control based on current-stress of bi-directional full-bridge DC-DC converters with dual-phaseshifting control[J].Transactions of China Electrotechnical Society,2016,31(22):100-106.
[17]江添洋,张军明,汪槱生.同步控制双向LLC谐振变换器[J].电工技术学报,2015,30(12):87-96.Jiang Tianyang,Zhang Junming,Wang Yousheng.Bidirectional LLC resonant converter with synchronous control method[J].Transactions of China Electrotechnical Society,2015,30(12):87-96.
[18]Alberto Rodríguez Alonso.An overall study of a dual active bridge for bidirectional DC/DC conversion[C]//IEEE Energy Conversion Congress and Exposition,Atlanta,GA,2010:5617847.
[19]吴俊娟,孙孝峰,邬伟扬.串联谐振变换器的扩展描述函数法建模研究[J].电力电子技术,2011,45(4):22-24.Wu Junjuan,Sun Xiaofeng,Wu Weiyang.Study of modeling of resonant converter based on extended describing function method[J].Power Electronics,2011,45(4):22-24.
[20]Sha Deshang,Guo Zhiqiang,Liao Xiaozhong.Cross-feedback output-current-sharing control for input-series-output-parallel modular DC-DC converters[J].IEEE Transactions on Power Electronics,2010,25(11):2762-2771.
[21]Shi Jianjiang,Luo Jie,He Xiangning.Commonduty-ratio control of input-series output-parallel connected phase-shift full-bridge DC-DC converter modules[J].IEEE Transactions on Power Electronics,2011,26(11):3318-3329.
[22]付超,孙贺,张建成,等.直流固态变压器新型均衡解耦控制策略[J].电网技术,2018,42(6):1945-1953.Fu Chao,Sun He,Zhang Jiancheng,et al.A novel decoupling strategy of balancing control for DC solid state transformer[J].Power System Technology,201842(6):1945-1953.
[23]赵彪,宋强,刘文华,等.用于柔性直流配电的高频链直流固态变压器[J].中国电机工程学报,2014,34(25):4295-4303.Zhao Biao,Song Qiang,Liu Wenhua,et al.Highfrequency-link DC solid state transformers for flexible DC distribution[J].Proceedings of the CSEE,2014,34(25):4295-4303.
[24]王瑾,陈曦,肖岚.新型输入并联输出串联直流变换器研究[J].南京师范大学学报(工程技术版).2012,12(1):1-4.Wang Jin,Chen Xi,Xiao Lan.Research on a novel input-parallel output-series connected HVDCconverters[J].Journal of Nanjing Normal University(Engineering and Technology Edition),2012,12(1):1-4.
[25]王子龙,肖岚,赵鹏.全桥直流变压器/变换器ISOP组合式系统的研究[J].中国电机工程学报,2014,34(33):5819-5826.Wang Zilong,Xiao Lan,Zhao Peng.Researches on combined input-series output-parallel systems composed of full-bridge DC transformers and converter[J]Proceedings of the CSEE,2014,34(33):5819-5826.
[26]Zhang Kai,Shan Zhenyu,Juri Jatskevich.Large-and small-signal average-value modeling of dual-activebridge DC-DC converter considering power losses[J].IEEE Transaction on Power Electronic,2017,32(3):1964-1974.
[27]李婧,袁立强,谷庆,等.一种基于双有源桥变换器损耗模型的效率优化方法[J].电工技术学报,2017,32(14):67-77.Li Jing,Yuan Liqiang,Gu Qing,et al.An efficiency optimization method in dual active bridge based on loss model[J].Transactions of China Electrotechnical Society,2017,32(14):67-77.
[2]李子欣,高范强,赵聪.电力电子变压器技术研究综述[J].中国电机工程学报,2018,38(5):1274-1289.Li Zixin,Gao Fanqiang,Zhao Cong.Research review of power electronic transformer technologies[J].Proceedings of the CSEE,2018,38(5):1274-1289.
[3]Shigenori Inoue,Hirofum Akagi.A bidirectional isolated DC-DC converter as a core circuit of the next-generation medium-voltage power conversion system[J].IEEE Transactions on Power Electronics,2007,22(2):535-542.
[4]Zhao Biao,Song Qiang,Liu Wenhua.Power characterization of isolated bidirectional dual-activebridge DC-DC converter with dual-phase-shift control[J].IEEE Transactions on Power Electronics,2012,27(9):4172-4176.
[5]Gabriel Ortiz,Michael Leibl,Jonas Huber,et al.Design and experimental testing of a resonant DC-DCconverter for solid-state transformers[J].IEEETransactions on Power Electronics,2017,32(10):7534-7542.
[6]李菊,阮新波.全桥LLC谐振变换器的混合式控制策略[J].电工技术学报,2013,28(4):72-79,94.Li Ju,Ruan Xinbo.Hybrid control strategy of full bridge LLC converters[J].Transactions of China Electrotechnical Society,2013,28(4):72-79,94.
[7]游洪程,蔡旭.应用于直流电网的直接耦合式直流变压器[J].中国电机工程学报,2017,37(9):2516-2523.You Hongcheng,Cai Xu.Direct-coupled DC transformers applied to DC gridss[J].Proceedings of the CSEE,2017,37(9):2516-2523.
[8]Zhao Biao,Song Qiang,Li Jianguo,et al.Modular multilevel high-frequency-link DC transformer based on dual active phase-shift principle for mediumvoltage DC power distribution application[J].IEEETransactions on Power Electronics,2017,32(3):1779-1791.
[9]陈申,吕征宇,姚玮.LLC谐振型软开关直流变压器的研究与实现[J].电工技术学报,2012,27(10):163-169.Chen Shen,LüZhengyu,Yao Wei.Research and verification on LLC resonant soft switching DC-DCtransformer[J].Transactions of China Electrotechnical Society,2012,27(10):163-169.
[10]李建国,赵彪,宋强,等.适用于中压直流配网的多电平直流链固态变压器[J].中国电机工程学报2016,36(14):3717-3725.LI Jianguo,Zhao Biao,Song Qiang,et al.DC solid state transformer based on multilevel DC link for medium-voltage DC distribution application[J].Proceedings of the CSEE,2016,36(14):3717-3725.
[11]Sixifo Falcones.A DC-DC multiport-converter-based solid-state transformer integrating distributed generation and storage[J].IEEE Transactions on Power Electronics,2013,28(5):2192-2203.
[12]Li X,Bhat A.Analysis and design of high-frequency isolated dual-bridge series resonant DC/DC converter[J].IEEE Transactions on Power Electronics2010,25(4):850-862.
[13]王聪,沙广林,王俊,等.基于双重移相控制的双有源桥DC-DC变换器的软开关[J].电工技术学报,2015,30(12):106-113.Wang Cong,Sha Guanglin,Wang Jun,et al.The analysis of zero voltage switching dual active bridge DC-DC converters based on dual-phase-shifting control[J].Transactions of China Electrotechnical Society,2015,30(12):106-113.
[14]程红,高巧梅,朱锦标,等.基于双重移相控制的双向全桥DC-DC变换器动态建模与最小回流功率控制[J].电工技术学报,2014,29(3):245-253.Cheng Hong,Gao Qiaomei,Zhu Jinbiao,et al.Dynamic modeling and minimum backflow power controlling of the bi-directional full-bridge DC-DCconverters based on dual-phase-shifting control[J].Transactions of China Electrotechnical Society,2014,29(3):245-253.
[15]于德,付超,王毅,等.隔离型双向直流变换器的最小回流功率移相控制方法[J].电工技术学报,2017,32(24):126-137.Yu De,Fu Chao,Wang Yi,et al.The phase-shifted control method of isolated bidirectional DC-DCconverter with minimum backflow power[J].Transactions of China Electrotechnical Society,201732(24):126-137.
[16]张勋,王广柱,王婷.双向全桥DC-DC变换器基于电感电流应力的双重移相优化控制[J].电工技术学报,2016,31(22):100-106.Zhang Xun,Wang Guangzhu,Wang Ting.Optimized control based on current-stress of bi-directional full-bridge DC-DC converters with dual-phaseshifting control[J].Transactions of China Electrotechnical Society,2016,31(22):100-106.
[17]江添洋,张军明,汪槱生.同步控制双向LLC谐振变换器[J].电工技术学报,2015,30(12):87-96.Jiang Tianyang,Zhang Junming,Wang Yousheng.Bidirectional LLC resonant converter with synchronous control method[J].Transactions of China Electrotechnical Society,2015,30(12):87-96.
[18]Alberto Rodríguez Alonso.An overall study of a dual active bridge for bidirectional DC/DC conversion[C]//IEEE Energy Conversion Congress and Exposition,Atlanta,GA,2010:5617847.
[19]吴俊娟,孙孝峰,邬伟扬.串联谐振变换器的扩展描述函数法建模研究[J].电力电子技术,2011,45(4):22-24.Wu Junjuan,Sun Xiaofeng,Wu Weiyang.Study of modeling of resonant converter based on extended describing function method[J].Power Electronics,2011,45(4):22-24.
[20]Sha Deshang,Guo Zhiqiang,Liao Xiaozhong.Cross-feedback output-current-sharing control for input-series-output-parallel modular DC-DC converters[J].IEEE Transactions on Power Electronics,2010,25(11):2762-2771.
[21]Shi Jianjiang,Luo Jie,He Xiangning.Commonduty-ratio control of input-series output-parallel connected phase-shift full-bridge DC-DC converter modules[J].IEEE Transactions on Power Electronics,2011,26(11):3318-3329.
[22]付超,孙贺,张建成,等.直流固态变压器新型均衡解耦控制策略[J].电网技术,2018,42(6):1945-1953.Fu Chao,Sun He,Zhang Jiancheng,et al.A novel decoupling strategy of balancing control for DC solid state transformer[J].Power System Technology,201842(6):1945-1953.
[23]赵彪,宋强,刘文华,等.用于柔性直流配电的高频链直流固态变压器[J].中国电机工程学报,2014,34(25):4295-4303.Zhao Biao,Song Qiang,Liu Wenhua,et al.Highfrequency-link DC solid state transformers for flexible DC distribution[J].Proceedings of the CSEE,2014,34(25):4295-4303.
[24]王瑾,陈曦,肖岚.新型输入并联输出串联直流变换器研究[J].南京师范大学学报(工程技术版).2012,12(1):1-4.Wang Jin,Chen Xi,Xiao Lan.Research on a novel input-parallel output-series connected HVDCconverters[J].Journal of Nanjing Normal University(Engineering and Technology Edition),2012,12(1):1-4.
[25]王子龙,肖岚,赵鹏.全桥直流变压器/变换器ISOP组合式系统的研究[J].中国电机工程学报,2014,34(33):5819-5826.Wang Zilong,Xiao Lan,Zhao Peng.Researches on combined input-series output-parallel systems composed of full-bridge DC transformers and converter[J]Proceedings of the CSEE,2014,34(33):5819-5826.
[26]Zhang Kai,Shan Zhenyu,Juri Jatskevich.Large-and small-signal average-value modeling of dual-activebridge DC-DC converter considering power losses[J].IEEE Transaction on Power Electronic,2017,32(3):1964-1974.
[27]李婧,袁立强,谷庆,等.一种基于双有源桥变换器损耗模型的效率优化方法[J].电工技术学报,2017,32(14):67-77.Li Jing,Yuan Liqiang,Gu Qing,et al.An efficiency optimization method in dual active bridge based on loss model[J].Transactions of China Electrotechnical Society,2017,32(14):67-77.