Focusing on inductive wireless power transfer (WPT), which relies on coil resonators and power converters, this book begins by providing the background and basic theories of WPT, which are essential for newcomers to the field. Then two major challenges of WPT – power transfer distance and efficiency – are subsequently addressed, and multi-resonator WPT systems, which not only offer a way to extend power transfer distance but also provide more flexibility, are investigated. Recent findings on techniques to maximize the power transfer efficiency of WPT systems, e.g. maximum efficiency point tracking, are also introduced. Without the constraint of cables, wireless power transfer (WPT) is an elegant technique for charging or powering a range of electrical devices, e.g. electric vehicles, mobile phones, artificial hearts, etc. Given its depth of coverage, the book can serve as a technical guideline or reference guide for engineers and researchers working on WPT.
Author(s): Wenxing Zhong, Dehong Xu, Ron Shu Yuen Hui
Series: CPSS Power Electronics Series
Publisher: Springer
Year: 2020
Language: English
Pages: 136
Tags: Power Electronics, Electrical Machines And Networks
Preface......Page 6
Contents......Page 8
Fundamentals of Magnetic Resonance Wireless Power Transfer......Page 12
1 Introduction to Magnetic Resonance WPT......Page 13
1.1 Nikola Tesla’s Early Work......Page 14
1.2 Inductive Power Transfer (IPT)......Page 15
1.3 Planar Wireless Charging Technology and Qi......Page 16
1.4 The Four-Coil System......Page 17
References......Page 18
2.1 From Coupled Inductors to Magnetic Resonance Coupling......Page 20
2.2.2 Induced Voltages, Currents and Gains......Page 23
2.2.3 Efficiency......Page 25
2.2.4 Output Power......Page 28
2.2.5 Input Impedance, Zero Phase Angle, and Bifurcation [5]......Page 29
References......Page 32
Multi-resonator WPT Systems......Page 33
3.1 Circuit Model [1]......Page 34
3.2.1 Coaxial Coils......Page 35
3.2.2 Non-coaxial Coils......Page 37
3.3 Efficiency Optimization Methodology [1]......Page 38
References......Page 40
4.1 Introduction......Page 41
4.2 Efficiency of a Straight Domino-Resonator System [1]......Page 42
4.3 Methodology for Power Flow Analysis [2]......Page 43
4.4 Effects of Cross-Coupling [2]......Page 45
4.5.1 Three-Resonator System......Page 48
4.5.2 n-Resonator System......Page 49
4.6 Summary......Page 51
References......Page 54
5.1 Introduction......Page 55
5.2 Model of the Circular Domino-Resonator System......Page 56
5.3 Simplified Analysis Without Cross-Couplings......Page 58
5.4 Optimization of Circular Domino-Resonator Systems with Cross-Couplings......Page 62
5.5 Practical Verification......Page 65
5.6 Discussion......Page 66
Reference......Page 67
6.2 Theoretical Analysis......Page 68
6.3 Computer-Aided Analysis and Verifications......Page 70
6.3.2 Use of the Inner Coil as Coil-1 and Outer Coil as Coil-a......Page 72
6.4 Experimental Verification......Page 73
6.4.1 Efficiency Evaluation......Page 76
6.5 Conclusion......Page 77
References......Page 78
Maximum Efficiency Operation......Page 79
7.1 Theory of Maximum-Efficiency-Operation WPT......Page 80
7.2.1 Efficiency Degradation Due to Variations in Magnetic Coupling......Page 81
7.2.2 Efficiency Degradation Due to Load Resistance Variation......Page 82
7.3.1 Using Standard DC–DC Converters on the Receiver Side......Page 83
7.3.2 Using Boost-Type Converters on the Receiver Side......Page 84
7.3.3 Using Transmitter-Side On–Off Keying (OOK) Modulation......Page 87
7.3.4 Using Reconfigurable Impedance Transformation Circuits......Page 88
7.3.5 Using Reconfigurable Coil-Resonant Circuits......Page 90
7.4 Review of MEO Control Schemes......Page 91
7.4.1 Perturbation and Observation (P&O)......Page 92
7.4.2 Calculating Optimal Control Variable Based on Coupling Estimation......Page 94
7.4.3 Voltage Ratio Control......Page 96
7.5.1 Light-Load Conditions (RL > RLOPT)......Page 97
7.5.3 Control Schemes Comparison......Page 98
References......Page 99
8.2 Searching for the Optimal Duty Cycle......Page 102
8.3 Experimental Verifications......Page 106
8.4 Conclusion......Page 108
9.1 Introduction......Page 109
9.2.1 Theoretical Analysis on WPT Systems with Output Rectifiers......Page 110
9.2.2 Theoretical Analysis on WPT Systems with Constant Output Voltage......Page 112
9.3 An OOK Modulated WPT System......Page 113
9.3.1 Analysis on the Effect of OOK......Page 114
9.4 Experimental Verifications......Page 116
9.5 Conclusion......Page 121
10.2 Use Receiving Coil Splitting to Enable High Efficiency for Smaller Load Resistances......Page 122
10.3.1 Extending High-Efficiency Region to the Lower Load Resistance Range......Page 128
10.3.2 Extending High-Efficiency Region to the Higher Load Resistance Range......Page 129
10.3.3 VA Rating Minimization or Power Maximization......Page 132
10.4 Experimental Verification......Page 133
10.5 Conclusion......Page 136
