Wireless Power Transfer
Description
Presents a detailed overview of multiple-objective wireless power transfer (WPT) technologies, including the latest research developments and emerging applications
Wireless Power Transfer: Principles and Applications offers comprehensive coverage of all key aspects of wireless power transfer (WPT) technologies, including fundamental theory, intelligent control, configuration analysis, and emerging power electronics techniques. This unique resource is the first book of its kind to provide in-depth discussion of energy transmission control schemes with emphasis on omni-directional vector control, energy-encryption-based security control, demand-based optimal designs for transmitter, pickup, and self-resonance coils, multiple-objective power distribution, and maximum efficiency and power control under various conditions.
In addition, this text:
* Presents the methodologies and approaches of emerging multiple-objective WPT technologies
* Discusses various applications for wireless charging techniques, including contactless power for electric vehicles, in-flight charging for unmanned aerial vehicles, and underwater wireless charging
* Covers both intermittent and continuous impedance matching methods for different classes of coils
* Features more than 400 high-quality illustrations and numerous figures and tables throughout
Wireless Power Transfer: Principles and Applications is an invaluable technical reference for academic researchers and industry professionals in power and energy engineering, and an excellent textbook for postgraduate courses in relevant areas of industrial and electronic engineering.
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Persons
Zhen Zhang, Ph.D., is a full professor with the School of Electrical and Information Engineering at Tianjin University. He has authored and co-authored numerous internationally referred papers as well as two books published by Wiley-IEEE Press and Cambridge University Press. Prof. Zhang is currently the Chair of IEEE Beijing Section IES Chapter (Tianjin) and an Associate Editor for the IEEE Transactions on Industrial Electronics, IEEE Transactions on Industrial Informatics and IEEE Industrial Electronics Magazine. He is the recipient of the Humboldt Research Fellowship, Carl Friedrich von Siemens Research Fellowship, Japan Society for the Promotion of Science Visiting Fellowship, 2020 Outstanding Paper Award for IEEE Transactions on Industrial Electronics, and IEEE J. David Irwin Early Career Award.
Hongliang Pang received the B.Eng. and M.Eng. degrees from Tianjin University, China in 2017 and 2020, respectively. He is currently working toward the Ph.D. degree in electrical and electronic engineering at the Department of Electrical and Electronic Engineering, the University of Hong Kong. He has published several technical papers and industrial reports in these areas. His current research interests include electric vehicle technologies, wireless power transfer and Power-electronic-based impedance matching.
Content
Part I: Introduction
Chapter 1: The Era of Wireless Power Transfer
1.1 The father of wireless power transfer - Nikola Tesla
1.2 Wireless power Transfer
1.3 About this book
Chapter 2: Inductive Power Transfer
2.1 Inductive power transfer
2.2 1-to-1 transmission
2.3 1-to-N transmission
2.4 What are differences between 1-to-1 and 1-to-N transmission
Part II: Design
Chapter 3: Design and Optimization for Coupled Coils
3.1 Introduction
3.2 Design considerations
3.3 Optimal design
3.4 Discussion
Chapter 4: Design and Optimization for Power Circuits
4.1 Impedance matching
4.2 DC/AC inverters
Part III: Control
Chapter 5: Control for Single Pickup
5.1 Review of control schemes
5.2 Maximizing efficiency control
Chapter 6: Control for Multiple Pickups
6.1 Introduction
6.2 Transmission strategy for transmitting side
6.3 Impedance matching strategy for multi-frequency transmission
6.4 Others
Chapter 7: Energy Security of Wireless Power Transfer
7.1 Introduction
7.2 Characteristic of frequency
7.3 Energy encryption
7.4 Verifications
7.5 Opportunities
Chapter 8: Omnidirectional Wireless Power Transfer
8.1 Introduction
8.2 Mathematic analysis
8.3 Design of transmitting coils for synthetic magnetic field
8.4 Design and control considerations for pickup coils
8.5 Load detection
8.6 Discussion
Part IV: Application
Chapter 9: WPT for High-Power Application - Electric Vehicles
9.1 Introduction
9.2 EV wireless charging
9.3 Electromagnetic field reduction
9.4 Key technologies
9.5 Summary
Chapter 10: WPT for Low-Power Applications
10.1 Portable consumer electronics
10.2 Implantable medical devices
10.3 Drones
10.4 Underwater wireless charging
1
The Era of Wireless Power Transfer
As one of the most epoch-making technologies, the wireless power transfer (WPT) can realize the energy transmission in a cordless way [1, 2], which is obviously changing our traditional usage pattern of the energy, thus promoting the pervasive application of sustainable energies into our daily life. Surprisingly, such a miracle technique is not anything new, yet the original concept can date back more than 100 years ago. The story should begin with a great man, namely Nikola Tesla, as shown in Figure 1.1.
1.1 The Father of Wireless Power Transfer - Nikola Tesla
About 130 years ago, the wirelessly transmitting power was successfully demonstrated by Nikola Tesla's series of experiments, where the Geissler tubes and incandescent light bulbs can be lighted from across a stage based on near-field inductive and capacitive coupling, as depicted in Figure 1.2. The key technique of such amazing experiments is to use Tesla coils, which are spark-excited radio-frequency resonant transformers, to generate a high alternating current (AC) voltage [3, 4]. More importantly, Tesla found that the transmission distance could be increased if the LC circuit of receivers can be tuned to resonance with the LC circuit of transmitters [5], namely resonant inductive coupling [4]. Nevertheless, such an imaginative technique failed to proceed with commercialization due to various limitations at that time, such as semiconductor materials, power electronic technologies, and manufacturing.
Tesla's attempting efforts on WPT technologies have never stopped since the beginning of this story. Then, his focus moved to a wireless power distribution system, which can wirelessly deliver the power directly to everywhere in the world. Borrowing from the idea of Mahlon Loomis [3], he developed a demonstrating system composed of balloons to suspend transmitting and receiving electrodes in the air above 9100-m altitude, because he believed that the low-pressure air at high altitude would allow higher voltage for long-distance power transmission. In 1899, Tesla build up a test facility at high altitude in Colorado Springs to further study the conductive characteristics of low-pressure air [3]. It is this famous experiment that led Tesla to incorrectly conclude that the entire Earth can be utilized to conduct electrical energy [3]. In addition, the potential of the Earth can be oscillated by driving AC pulses into the Earth at its resonant frequency using a grounded Tesla coil. In such a way, he believed that the AC power can be picked up at everywhere around the world using a similar capacitive antenna tuned to resonance with the Earth [3, 6].
Figure 1.1 Nikola Tesla [3].
Source: Wikimedia Commons.
Figure 1.2 Demonstrations of wireless lighting by Tesla.
Source: Ref. [2] Nikola Tesla/Wikimedia Commons/Public Domain.
Figure 1.3 Tesla's unsuccessful Wardenclyffe power station.
Source: Ref. [2] Nikola Tesla/Wikimedia Commons/Public Domain.
Then, Tesla boldly proposed a "World Wireless System" to deliver both the information and the power around the world [3]. In 1901, a large high-voltage wireless power station, namely Wardenclyffe Tower, was built at Shoreham in New York, as depicted in Figure 1.3. Unfortunately, this project had to be halt due to dried-up investment by the year 1904. Despite all this, Nikola Tesla really redefined the energy transmission and opened up a brand-new research field, who is well deserved to be called the Father of Wireless Power Transfer [7].
1.2 Wireless Power Transfer
As one of the revolutionary technologies, WPT can realize the transmission of electric energy from the transmitting end to the desired pickup device in a contactless manner. From the perspective of the transmission distance, the WPT can be mainly divided to near-field transmission and far-field transmission. On the one hand, the near-field power transfer is based on the electromagnetic field coupling theory, including the inductive and capacitive coupling mechanisms. On the other hand, the far-field power transfer can be realized by means of acoustic, optical, and microwave methods, which are applied in low-power sensor networks and military fields. The different wireless power technologies are shown in Table 1.1.
1.2.1 Acoustic
The acoustic power transfer can achieve the wireless power transmission in the form of acoustic waves or mechanical vibrations. As shown in Figure 1.4, the system of the acoustic power transfer mainly includes four constituent units, namely the primary AC power supply, the primary and pickup sensors that realize the conversion of electrical energy and mechanical acoustic energy, and the energy pickup side.
The far-field power transfer can be realized in the acoustic mechanism with the help of the ultrasonic frequency of vibration. Meanwhile, a variety of transmission media, including living tissue, metal materials, and air, are suitable for the acoustic mechanisms. Nevertheless, the acoustic power transfer faces the following three challenges. Firstly, the principle of spatial resonance puts forward special requirements for the placement position of the pickup coil, which limits the application scenario of this technology. Secondly, the technology lacks complete and clear theoretical analysis, which hinders the further development and wide application of the technology. Finally, the design of sensor is an important part of this technology which needs to comprehensively consider the power, efficiency of the system, and the impact of reflections [8].
1.2.2 Optical
As shown in Figure 1.5, the optical WPT uses the laser as the medium to transmit energy to the pickup coil. This technology is mainly used in military or aerospace fields that require long-distance energy transmission. Compared with other energy transmission mechanisms, this technology has the following characteristics: the realization of the ultralong-distance transmission, the realization of the centralized and directional energy transmission, and zero interference to radio-frequency applications. Meanwhile, the optical WPT faces the challenges including the low conversion efficiency between light and electricity and the danger of laser radiation. Since the twenty-first century, optical WPT has also been used in industrial consumer electronics or low-power sensors [9].
Table 1.1 Different wireless power technologies.
Technology Range Directivity Frequency Antenna devices Current and/or possible future applications Inductive coupling Short Low Hz to MHz Wire coils Electric tooth brush and razor battery charging, induction stovetops, and industrial heaters Resonant inductive coupling Mid Low kHz to GHz Tuned wire coils and lumped element resonators Charging portable devices (Qi), biomedical implants, electric vehicles, powering buses, trains, MAGLEV, Radio frequency identification (RFID), and smartcards Capacitive coupling Short Low kHz to GHz Metal plate electrodes Charging portable devices, power routing in large-scale integrated circuits, smartcards, and biomedical implants Magnetodynamic coupling Short N.A. (Not applicable) Hz Rotating magnets Charging electric vehicles and biomedical implants Microwaves Long High GHz Parabolic dishes, phased arrays, and rectennas Solar power satellite, powering drone aircraft, and charging wireless devices Light waves Long High =THz Lasers, photocells, and lenses Charging portable devices, powering drone aircraft, and powering space elevator climbersFigure 1.4 Acoustic wireless power transfer.
Figure 1.5 Optical wireless power transfer.
1.2.3 Microwave
Microwave power transfer technology is a typical far-field wireless power transmission mechanism, which is applied in the low-power sensor networks, space, and military fields. The principle and components of the microwave power transfer system are depicted in Figure 1.6. At the transmitting part, the microwave is generated by the microwave generator and transmitted through the coax-waveguide-adapted and waveguide circulator, which reduces the external radiation caused by microwave. Then, the tuner and directional coupler device are used to realize the separation of radiation signals according to different propagation directions, ensuring the propagation of radiation in the air. In the pickup part, the microwave radiation is received through the receiving antenna and...
