CPSS Power Electronics Series Deshang Sha Guo Xu High-Frequency Isolated Bidirectional Dual Active Bridge DC–DC Converters with Wide Voltage Gain CPSS Power Electronics Series Series editors Wei Chen, Fuzhou University, Fuzhou, Fujian, China Yongzheng Chen, Liaoning University of Technology, Jinzhou, Liaoning, China Xiangning He, Zhejiang University, Hangzhou, Zhejiang, China Yongdong Li, Tsinghua University, Beijing, China Jingjun Liu, Xi’an Jiaotong University, Xi’an, Shaanxi, China An Luo, Hunan University, Changsha, Hunan, China Xikui Ma, Xi’an Jiaotong University, Xi’an, Shaanxi, China Xinbo Ruan, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, China Kuang Shen, Zhejiang University, Hangzhou, Zhejiang, China Dianguo Xu, Harbin Institute of Technology, Harbin, Heilongjiang, China Jianping Xu, Xinan Jiaotong University, Chengdu, Sichuan, China Mark Dehong Xu, Zhejiang University, Hangzhou, Zhejiang, China Xiaoming Zha, Wuhan University, Wuhan, Hubei, China BoZhang,SouthChinaUniversityofTechnology,Guangzhou,Guangdong,China Lei Zhang, China Power Supply Society, Tianjin, China Xin Zhang, Hefei University of Technology, Hefei, Anhui, China Zhengming Zhao, Tsinghua University, Beijing, China Qionglin Zheng, Beijing Jiaotong University, Beijing, China Luowei Zhou, Chongqing University, Chongqing, China This series comprises advanced textbooks, research monographs, professional books,andreferenceworkscoveringdifferentaspectsofpowerelectronics,suchas VariableFrequencyPowerSupply,DCPowerSupply,MagneticTechnology,New Energy Power Conversion, Electromagnetic Compatibility as well as Wireless Power Transfer Technology and Equipment. The series features leading Chinese scholars and researchers and publishes authored books as well as edited compilations. It aims to provide critical reviews of important subjects in the field, publish new discoveries and significant progress that has been made in develop- ment of applications and the advancement of principles, theories and designs, and report cutting-edge research and relevant technologies. The CPSS Power Electronics series has an editorial board with members from the China Power Supply Society and a consulting editor from Springer. Readership: Research scientists in universities, research institutions and the industry, graduate students, and senior undergraduates. More information about this series at http://www.springer.com/series/15422 Deshang Sha Guo Xu (cid:129) High-Frequency Isolated Bidirectional Dual Active – Bridge DC DC Converters with Wide Voltage Gain 123 Deshang Sha GuoXu AdvancedPower Conversion Center, AdvancedPower Conversion Center, Schoolof Automation Schoolof Automation Beijing Institute of Technology Beijing Institute of Technology Beijing Beijing China China ISSN 2520-8853 ISSN 2520-8861 (electronic) CPSSPower Electronics Series ISBN978-981-13-0258-9 ISBN978-981-13-0259-6 (eBook) https://doi.org/10.1007/978-981-13-0259-6 LibraryofCongressControlNumber:2018939940 ©SpringerNatureSingaporePteLtd.2019 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. 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Printedonacid-freepaper ThisSpringerimprintispublishedbytheregisteredcompanySpringerNatureSingaporePteLtd. partofSpringerNature Theregisteredcompanyaddressis:152BeachRoad,#21-01/04GatewayEast,Singapore189721, Singapore Preface Bidirectional DC–DC converters are widely used as power interfaces for many applications that need both changing and discharging of the energy storage com- ponents, such as batteries, super-capacitors. Among various types of bidirectional DC–DC converters, dual active bridge (DAB) converter has become popular and preferred topology during these years for its attractive advantages including sym- metrical structure, zero-voltage switching, bidirectional power transfer capability, and high-power density. This book presents different DAB converter topologies and power control strategies to achieve better power conversion performances for applications requiring both bidirectional power flow and galvanic isolation. The studied topologies can be used for applications needing a relatively wide voltage ranges such as energy storage system, automotive applications, solid-state transformer (SST)-based DC fast charger. The converter working principles, power transfer characteristics,converterlossesareanalyzedinthisbook.Basedonthat,thepower controlstrategiesareappliedtoachievebetterperformanceaimedatdifferentcontrol goals. This book will benefit the researchers and engineers inthe fieldof topology and control for dual active bridge isolated bidirectional DC–DC converters. The outcomes will enable effective development and high-quality mass production of novel high-performance DC–DC converters for the aforementioned bidirectional power applications. The main objectives are as follows, 1) To review and summarize the existed mainstream topologies and control methods for dual active bridge converters which are viewed as challenging research and application topic in the field of electrical engineering. 2) To develop new topologies for the applications that require wide voltage gain range due to the interfacing with the batteries. These applications include energy storage system, automotive applications, SST-based DC fast charger. 3) To develop effective and simple control methods to achieve reduced current stress and wide ZVS ranges for the bidirectional dual active bridge DC–DC converters. v vi Preface 4) To present useful methodologies and philosophies to develop new topologies andcontrolsforisolatedbidirectionalDC–DCconvertertoachievewidevoltage range. This book consists of 12 Chapters based on our several research projects, and covering the aspects of converter topologies and power control strategies for DAB converters. Like most books, this book starts with an introduction in Chap. 1 to present a brief introduction focusing on the applications and classifications of bidirectional DC–DC converters, review of the control methods for dual active bridgecontrol,andkeyissuesofDABconverters.Fortherestofthecontents,from thetopologypointofview,thisbookcanbedividedintotwoparts.Thefirstpartis focusedontopologyandcontrolforvoltagefeddualactivebridgeconverterswhich arefromChaps.2to6,andthesecondpartpresentsthetopologiesandcontrolsfor current-fed dual active bridge converters which are included from Chaps. 7 to 12. The detail organization of the book content is summarized in Chap. 1. The authorswish toexpresstheir sincerethanks toProf. ZhiqiangGuo, Beijing Institute of Technology for his contribution on the three-level DAB converter research and other contributions to this book. The author would also like to acknowledge the contributions of Mr. Yaxiong Xu and Dr. Jiankun Zhang on the voltage-typeDABconverters, Dr.XiaoWang,Mr.Deliang Chen,Mr.LingyuXu, Mr. Wenqi Yuan on the current-fed DAB converters. The author would like to thank for the support from the National Natural ScienceFoundationofChinaunderGrant51577012,from StateKeyLaboratoryof Alternate Electrical Power System with Renewable Energy Sources under Grant LATS17019, from Key Laboratory of Solar Thermal Energy and Photovoltaic System of Chinese Academy of Sciences. The author would also like to thank their families who have given tremendous supportallthetime. Finally,theauthorsareextremelygratefultoSpringerandthe editorial staff for the opportunity to publish this book and help in all possible manners. Beijing, China Deshang Sha Guo Xu Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Application of Bidirectional DC–DC Converter . . . . . . . . . . . . 1 1.1.1 Energy Storage System for Microgrid or Smart Grid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1.2 Automotive Applications . . . . . . . . . . . . . . . . . . . . . . 3 1.1.3 SST Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Classification of Bidirectional DC–DC Converter . . . . . . . . . . . 5 1.2.1 Non-isolated and Isolated DC–DC Converter. . . . . . . . 5 1.3 Isolated Bidirectional DC–DC Converter . . . . . . . . . . . . . . . . . 7 1.3.1 PWM Controlled, Frequency Controlled and Phase Shift Controlled Bidirectional DC–DC Converter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3.2 Current-Fed DAB Converter . . . . . . . . . . . . . . . . . . . . 9 1.3.3 Multi-level DAB DC–DC Converter . . . . . . . . . . . . . . 11 1.4 Research Literature of DAB Converters . . . . . . . . . . . . . . . . . . 12 1.4.1 Basic Principle of DAB Converters. . . . . . . . . . . . . . . 12 1.4.2 Control of Voltage-Fed DAB Converters. . . . . . . . . . . 13 1.4.3 Control of Current-Fed DAB Converters . . . . . . . . . . . 15 1.5 Key Issues of DAB Converter. . . . . . . . . . . . . . . . . . . . . . . . . 16 1.5.1 ZVS Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.5.2 Non-active Power and Current Stress. . . . . . . . . . . . . . 16 1.5.3 Wide Voltage Gain. . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.6 Organization of the Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2 Unified Boundary Trapezoidal Modulation Control for Dual Active Bridge DC–DC Converter . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.1 Fixed Duty Cycle Compensation and Magnetizing Current Design for DAB DC–DC Converter with Trapezoidal Modulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 vii viii Contents 2.1.1 Conventional Trapezoidal Modulation (TZM) . . . . . . . 26 2.1.2 ZVS Conditions for DAB Converter with Conventional TZM Control. . . . . . . . . . . . . . . . . . . . . 27 2.1.3 Proposed Fixed Duty Cycle Compensation . . . . . . . . . 29 2.1.4 Magnetizing Current Design to Achieve ZVS for S and S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 7 8 2.2 Power Transfer Characteristic and Selections of Duty Cycles and Phase Shift Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2.2.1 Selections of Duty Cycles and Phase Shift Ratio for Minimum RMS Circulating Current. . . . . . . . . . . . . . . 33 2.2.2 Maximum Power Transfer Point . . . . . . . . . . . . . . . . . 36 2.3 Boundary TZM Control and Its Implementation . . . . . . . . . . . . 37 2.3.1 Boundary TZM Control . . . . . . . . . . . . . . . . . . . . . . . 37 2.3.2 Implementation of Boundary TZM Control . . . . . . . . . 38 2.4 Experimental Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2.5 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 3 Hybrid-Bridge-Based DAB Converter with Wide Voltage Conversion Gain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 3.1 Working Principle of Hybrid-Bridge-Based DAB Converter . . . 47 3.1.1 Topology and Modulation Scheme for Hybrid-Bridge-Based DAB Converter . . . . . . . . . . 48 3.1.2 Working Stages of the Converter . . . . . . . . . . . . . . . . 50 3.2 ZVS Conditions and Power Control. . . . . . . . . . . . . . . . . . . . . 52 3.2.1 Current Range for ZVS . . . . . . . . . . . . . . . . . . . . . . . 52 3.2.2 Proposed VM Control to Ensure Wide ZVS Range . . . 55 3.3 Converter Performance with Proposed Voltage Match Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 3.3.1 Voltage Gain Under VM Control . . . . . . . . . . . . . . . . 57 3.3.2 Power Transfer Characteristics with VM Control . . . . . 58 3.3.3 Switches ZVS Discussion . . . . . . . . . . . . . . . . . . . . . . 60 3.4 Implementation of the Proposed Control . . . . . . . . . . . . . . . . . 60 3.5 Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.5.1 General Comparisons . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.5.2 Comparison of Inductor RMS Current and Total Conduction Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 3.6 Experimental Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 3.7 Discussion and Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . 69 3.8 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Contents ix 4 Dual-Transformer-BasedDAB Converter withWide ZVS Range for Wide Voltage Gain Application. . . . . . . . . . . . . . . . . . . . . . . . . 71 4.1 Converter Topology and Operation Principle . . . . . . . . . . . . . . 71 4.1.1 Topology and Modulation Schedule Using Phase Shift Control . . . . . . . . . . . . . . . . . . . . . . . . . . 72 4.1.2 Working Stages of the Converter . . . . . . . . . . . . . . . . 73 4.2 ZVS Constraints and Control. . . . . . . . . . . . . . . . . . . . . . . . . . 75 4.2.1 Current Range for ZVS . . . . . . . . . . . . . . . . . . . . . . . 75 4.2.2 ProposedControlLawtoAchieveFullRangeofZVS for S , S , S and S . . . . . . . . . . . . . . . . . . . . . . . . . 78 1 2 5 6 4.2.3 Transformer Turns Ratio Consideration and Extension of ZVS Range for S and S . . . . . . . . . . . . 79 3 4 4.3 Converter Characteristics with Proposed Control. . . . . . . . . . . . 80 4.3.1 Power Characteristics Under Proposed Control. . . . . . . 80 4.3.2 Implementation of the Proposed Control . . . . . . . . . . . 81 4.4 Design Consideration and Comparison. . . . . . . . . . . . . . . . . . . 82 4.4.1 Leakage Inductance Design. . . . . . . . . . . . . . . . . . . . . 83 4.4.2 Turns Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 4.5 Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 4.5.1 Device RMS and Peak Current Comparison. . . . . . . . . 85 4.5.2 ZVS Range Comparison. . . . . . . . . . . . . . . . . . . . . . . 86 4.5.3 Transformer Size Comparison. . . . . . . . . . . . . . . . . . . 86 4.6 Experimental Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 4.7 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 5 Blocking-Cap-Based DAB Converters. . . . . . . . . . . . . . . . . . . . . . . 97 5.1 Topology of the Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 5.2 Typical Waveforms of the Converter . . . . . . . . . . . . . . . . . . . . 97 5.3 Working Stages of the Converter. . . . . . . . . . . . . . . . . . . . . . . 99 5.3.1 Full-Bridge Operation Mode . . . . . . . . . . . . . . . . . . . . 99 5.3.2 Half-Bridge Operation Mode. . . . . . . . . . . . . . . . . . . . 101 5.4 ZVS Conditions of the Converter. . . . . . . . . . . . . . . . . . . . . . . 103 5.5 Power Transfer Characteristic and ZVS Region Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 5.5.1 Power Transfer Characteristic . . . . . . . . . . . . . . . . . . . 105 5.5.2 ZVS Region. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 5.5.3 RMS Current Comparison. . . . . . . . . . . . . . . . . . . . . . 108 5.6 Experimental Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 5.6.1 Rated Load (1 kW) . . . . . . . . . . . . . . . . . . . . . . . . . . 109 5.6.2 Light Load (270 W). . . . . . . . . . . . . . . . . . . . . . . . . . 111 5.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114