Shuo Wang. Research of Inductive Power Transfer System for Electric Vehicle. Faculty of Engineering and Information Technology. Doctor of Philosophy

Transcription

1 Faculty of Engineering and Information Technology Research of Inductive Power Transfer System for Electric Vehicle A thesis submitted for the degree of Doctor of Philosophy Shuo Wang (2016)

2 Title of the thesis: Research of Inductive Power Transfer System for Electric Vehicle Ph.D. student: Shuo Wang Supervisor: A/Prof. Youguang Guo Co-Supervisor: Dr. Li External Supervisor: Prof. David Dorrell Address: School of Electrical, Mechanical and Mechatronic Systems University of Technology Sydney, NSW 2007, Australia

3 Certificate of Original Authorship I certify that the work in this thesis has not previously been submitted for a degree nor has it been submitted as part of requirements for a degree except as fully acknowledged within the text. I also certify that the thesis has been written by me. Any help that I have received in my research work and the preparation of the thesis itself has been acknowledged. In addition, I certify that all information sources and literature used are indicated in the thesis. Signature of Student: Shuo Wang Date: i

4 Acknowledgments My thesis could not have come to fruition without the assistance of many contributors. Hereby, I would express my deep gratitude to my supervisors Professor David Dorrell, Associate Professor Youguang Guo and Dr. Li. Professor Dorrell supported me with great direction, advices and any other helps in my research. His optimism, patience, motivation, and immense knowledge, has been inspiring me in the past four years. His patient and guidance on solving problems, writing reports and oral communicating with profession rewards my entire research life. Associate Professor Guo spent plenty of time discussing from experiment design to thesis writing with me and gave me many great advices. He is a model for me in professional integrity. I am grateful to my co-supervisor Dr Li for his support with my presentations and reviewing the draft. I would also express my gratitude to Associate Professor Peter Watterson, Dr Paul Walker Dr. Guangzhong Xu, Dr. Chengcheng Liu, Mr. Russell Nicolson, and Mr. Laurence Stonard, for their help with my research. I would like to thank my colleagues, Dr. Lei Zhang, Dr. Jiageng Ruan, Dr.Sangzhi Zhu, Dr. Xingxing Zhou, Dr. Tianxiao Zhang, Dr. Yu Wang, Dr. Jinglai Wu, and Mr. Jianwei Zhang for their supports. I also wish to gratefully acknowledge the consistent financial support of the following agents: China Scholarship Council (CSC) and University of Technology, Sydney (UTS). Most especially to my family, words alone cannot express what I own them for their encouragement and whose patient love enabled me to complete this thesis. Firstly, it is my father Yanzhi Wang my my mother Huapeng Wu. I left China for my study in Australia and ii

5 couldn t visit my parents regularly during my past 4 years. My parents never said a word about my absent as their child but just showed their understanding. Secondly, I would like thank my unle Dehong Yu and aunt Huayou Wu. They taught me so much, from living in Australia to how to do research. Finally, I would like to thank my wife, Hongjun Qiao. She came to Australia to support my study and always encourage me. Our time here together in Australia would be my best memories. iii

6 Publications and Conference Contributions The following publications are part of the thesis Peer reviewed international scientific journal publications 1. S. Wang and D. G. Dorrell, "Loss analysis of circular wireless EV charging Coupler," in IEEE Trans. Magn., vol. 50, no. 11, pp. 1-4, Nov S. Wang and D. G. Dorrell, "Copper loss analysis of EV charging coupler," IEEE Trans.Magn., vol. 51, no. 11, pp. 1-4, Nov S. Wang, D. G. Dorrell, Y. Guo and M. F. Hsieh, "Inductive charging coupler with assistive coils," IEEE Trans. Magn., vol. 52, no. 7, pp. 1-4, July Peer reviewed international scientific conference publications 1. S. Wang and D. G. Dorrell, "Review of wireless charging coupler for electric vehicles", Proc. IEEE 39th Annu. Conf. Ind. Electron. Soc. (IECON), pp S. Wang and D. Dorrell, "Simulation of electric vehicle inductive charging system," 2015 IEEE 11th International Conference on Power Electronics and Drive Systems, Sydney, NSW, iv

7 Abstract Electric vehicles are a promising option for future transportation. The technology related to these have undergone rapid development over the last two decades and there are now many commercial electric vehicles available on the market. However, consumers still suffer from the "range anxiety" due to the limited driving range and long recharging time (refuelling time) compared to traditional internal combustion engine vehicles. Wireless charging is an alternative recharging option; currently the usual recharging method uses plug-in charging. With wireless charging, the connection between grid and vehicle can be established in less than a second without any manual operation. Therefore, recharging EVs can take place during a short stop or in motion. This means that there are more recharging windows available during vehicle use which would effectively extend the range of the vehicle and reduce consumers "range anxiety". This work is divided into three parts. The first part addresses the background and reviews the literature on EV recharging technologies. This is formed from first two chapters: Chapter 1 provides the introduction and outline of this thesis; Chapter 2 puts forward a literature review of the state of the art of recharging technology. The design of the wireless charging coupler is reviewed in this chapter. The second part is the study of the inductive charging system. Chapter 3 introduces the wireless charging pad analysis, which includes a circular pad and a rectangular pad analysis. The parameters of the pads are analysed. An analytical and numerical combined method for resistance analysis is introduced to wireless charging coupler resistance analysis which is v

8 the first contribution of this research. And Chapter 4 proposes a pad geometry with assistive coils which is a new arrangement that improves the coil coupling which is the secondary contribution of this study. Chapter 5 analyses the inductive power transfer system at circuit level, and experiment validation is carried out. Finally, conclusions and future work are given in Chapter 6. Keywords: EV, Wireless charging technology, Pad design, Pad analysis, Inductive charging system analysis. vi

9 Contents Certificate of Original Authorship... i Acknowledgments... ii Publications and Conference Contributions... iv Abstract... v List of Tables... xi List of Figures... xii Nomenclature... xvii Chapter Introduction Background Research Objectives Thesis Outline Reference... 6 Chapter Literature Review of EV Charging Methods Conductive charging method Single Stage Charger Two Stage Charger Off Board Charger Wireless Charging Methods EV Wireless Charging Technologies Magnetic Resonance Coupling Transfer Permanent Magnet Coupling Inductive Charging Method Review of EV Inductive Charging Technology vii

10 2.3.1 Coupler Power Source Compensation Stationary Wireless Charging Coupler On-Line/In-Motion Charging Discussion Summary References Chapter Analysis of Wireless EV Charging Coupler Introduction Circular Pad Structure Power Levels Self and Mutual Inductances of Coils Modelling of the IPT system Pad Analysis Analysis Methods Simulation Environment Simulation Result Copper Loss analysis Skin and Proximity Effect Loss and Calculation Method Loss Analysis of a Conductor Wire Geometric Modelling Coupler Model and Results Rectangular Pad Analysis Rectangular Pad Simulation Experiment Validation Summary Reference viii

11 Chapter Inductive Charging Coupler with Assistive Coils Introduction Wireless Charging Systems Two Winding Structure Four Winding Structure Proposed Coupler with Assistive Coils Circuit Model for Proposed Coupler Simulation Results Circuit Analysis Summary References Chapter IPT System Analysis Circuit Analysis with Compensation System Efficiency Relationship with Rload Secondary Side Output Current Efficiency with the mutual inductance IPT System Performance versus Frequency Impedance Analysis System Simulation DC Input Simulation Full bridge Inverter Phase shift Control IPT System Simulation Results Charger with Three Phase AC Source Simulation Results Experiment Coupler setup ix

12 5.3.2 Power Electronics setup Experiment Result Summary References CHAPTER Conclusions and Future Work Conclusions Future Work x

13 List of Tables Table 2-1. Levels of EV chargers... 8 Table 2-2. Battery Charging Methods [2.7] Table 2-3 General Parameters for Three Generations of On-Line EV Charging Table 3-1. Basic Geometrical Parameters Table 3-2. Ferrite Material Characteristics Table 3-3. Parameters of the Wireless Charger Table 3-4. Parameters of the Wireless Charger Table 3-5. Parameters of Simulated Wires Table 3-6. Copper Loss of Primary Side Winding Types 2 and 3 at 20 khz Table 3-7. Rectangular Pad Parameters Table 3-8. Inductance from Experiment and Simulation Table 3-9. Measured Laid and calculated k with spacing Table 4-1 Parameters of Simulated Coupler Table 4-2 Inductance Matrix of Four Coils Table 4-3 Coupling Coefficient Matrix of Four Coils Table 5-1 Parameters for Efficiency Analysis Table 5-2. Frequency Analysis Parameters Table 5-3 Parameters of the IPT system Table 5-4. Output Power with Phase Shift Angle Table 5-5. System Efficiency Versus Load xi

14 List of Figures Fig A unidirectional topology used for Level 1 chargers Fig. 2.2 A unidirectional topology for Levels 1 and 2 chargers Fig A bidirectional topology for Level 3 chargers Fig Structure for conductive charging Fig Classification of conductive chargers Fig AC/DC conventional boost rectifier [8] Fig Dual active bridge DC/DC converter Fig General structure for Level 3 fast Charging Fig. 2.9 Wireless charging technology Fig MRCT EV charging system Fig General structure of the IPT system Fig Full bridge inverter Fig Basic compensation topology Fig IPT system: a) early IPT charging system, b) IPT charging system with compensation Fig Flux of circular pad Fig Top view and cross view of a flux pipe pad Fig Structure of DD pad: (a) top view (b) cross view Fig A possible lumped on road charging Fig Three phase track topologies: (a) bipolar and (b) unipolar Fig The top view and cross view of OLEV power transfer system: (a) dual type and (b) mono type Fig Geometry of circular pad Fig Concept of mutual inductance using two magnetically coupled loops Fig Circuit model of IPT system Fig Circuit model using equivalent source for coupler windings Lp and Ls xii

15 Fig Circular pad full scale FEA simulation model Fig Maxwell 3D representation of one-6th section Fig Coupling factor k for transformer with and without ferrite cores Fig Flux density in the ferrite cores Fig Voltages of secondary winding and capacitor Fig Ohmic losses in the shield and ferrite core Fig Flux Leakage Fig Force on the winding Fig Concept of skin and proximity effects on stranded and bundled conductors Fig Simulation model of wires a) single conductor; b) 61 strands model; c) 349 strands Fig Loss distribution in a single conductor Fig Loss of single conductor wire verse frequency and radius Fig (a) Skin effect factor of wires; (b) Proximity effect G factor of wires Fig (a) Maxwell 3D representation of one-sixth section; (b) The magnetic field strength along the wire over time Fig The magnetic field strength over winding Fig Simulation model of rectangular pad: a) coupler model side view, b) top view of primary side coupler Fig Self-inductances of primary and secondary windings and mutual inductance with 186 mm ferrite bar on both sides Fig Mutual inductance versus misalignment with 186 mm ferrite bar on both sides 87 Fig Mutual inductance versus air bap distance with 186 mm ferrite bar on both sides Fig Coupling coefficient versus misalignment and air gap distance with 186 mm ferrite bar on both sides Fig Secondary side coil with 93 mm ferrite bar simulation Fig Inductance of primary and secondary winding and mutual inductance with 93 mm ferrite bar on secondary side Fig Mutual inductance versus air gap distance with 93 mm ferrite bar on secondary side xiii

16 Fig Mutual inductance versus misalignment with 93 mm ferrite bar on secondary side Fig Coupling coefficient versus misalignment and air gap distance with 93 mm ferrite bar on secondary side Fig FEA model for secondary side coil only pad Fig Inductance of primary and secondary winding and mutual inductance of secondary side coil only pad Fig Mutual inductance versus air gap distance with secondary side coil only pad Fig Mutual inductance versus misalignment with secondary side coil only pad Fig FEA model for coil only pad Fig Inductances of primary and secondary windings, and mutual inductance of coil only pad Fig.3.36 Mutual inductance versus air gap distance with coil only pad Fig Mutual inductance versus misalignment with coil only pad Fig Comparison of mutual inductance of different pads Fig Rectangular pad setup Fig Experiment and FEA results of coupling coefficient k Fig Wireless charging circuit Fig General structure for series-series compensation Fig Simulation results: (a) uncompensated circuit efficiency and power output, (b) SS compensated efficiency and power output Fig General structure for four-coil system Fig General structure for four-coil system: a) 3D view of transformer; b) top view of primary coupler; c) side view of primary coupler Fig Circuit model for proposed coupler with assistive coil system Fig Coupling coefficient via airgap length` Fig Two-coil system characteristic with C1 and C Fig Proposed coupler optimisation (efficiency and power maps) Fig Efficiency versus Rload Fig Efficiency map of mutual inductance and Rload xiv

17 Fig Pout and efficiency versus HF power source frequency Fig The frequency analysis: a) impedance verse frequency, b) Phase angle versus frequency Fig IPT system simulation model Fig Full bridge inverter Fig The phase shift control for full bridge Inverter Fig Full bridge output voltage and output current Fig Load voltage Vload and current Iload Fig Output power (top) and input power waveforms (bottom) Fig Inverter output voltage and current at α = Fig Output power (top) and input power waveforms at α =120 o Fig Output power and input power versus phase shift angle Fig Efficiency versus phase shift angle Fig Simulation model of IPT system with three phase input Fig Output current of three phase rectifier Fig Three phase rectifier DC link voltage Fig Three phase IPT system input power and output power Fig IPT experiment circuit Fig Test rig: primary side Fig Test rig: coupler and load Fig a) Coupler primary side, and b) Coupler Fig Rectifier module and IGBT module for experiment Fig Schematic diagram of gate drive Fig PCB view of gate drive Fig DSP output, gate drive signal and the inverter output Fig Time delay between the drive signal and the output voltage Fig The voltage and current inputs of the primary side Fig The voltage, current and power to the load Fig Inverter output voltage and current at 21 khz xv

18 Fig Inverter output voltage and current at 20 khz Fig System efficiency versus load resistance xvi

19 Nomenclature Global abbreviations used in this thesis AC = Alternating current CO2 = Carbon dioxide DC = Direct current EMI = Electromagnetic interface EV = Electric vehicle FEA = Finite element analysis FEM = Finite element method HEV = Hybrid electric vehicle HF = High frequency MRCT = Magnetic resonance coupling transfer PFC = Power factor correction PMCT = Permanent magnet coupling transfer SWC = Stationary wireless charging WPT = Wireless power transfer xvii