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Title: Techniques of efficient power transfer in wireless communication systems
Author: Zhuang, Yuan
ISNI:       0000 0004 7970 427X
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2019
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Efficient power transfer in wireless communication system is engineering the electronic signal propagation path to maximize the transfer power and efficiency to the load or minimize the signal reflection from the load. The modern wireless communication systems require not only reliable signal and power transmission but also high-efficiency propagation as well for both the cost-effective and environmental friendly purpose. The purpose of this thesis is to conduct a comprehensive research into the efficient power transfer of systems. The main contributions of this thesis are laid in three areas: The first area focuses on improving the efficiency of a power amplifier (PA) over an ultra-wide bandwidth. Two designs are presented in this part. In the first design, an optimal impedance contour is designed considering both frequency band and desired output power rather than an optimal impedance point of the traditional method. The second design presents a novel general design method of frequency varying impedance matching using stochastic reduced order models and Voronoi partition. The performance of the presented PAs outperforms existing PAs which demonstrates the excellence of the proposed method. The second area focusses on the impedance variation caused by the magnetic saturation in the magnetic energy harvesting of an AC power line. This design introduces a novel artificial magnetic field to manipulate the dominant magnetic field of power lines to compress the saturation for higher harvested power. The last area concentrates on improving the transfer efficiency of the wireless power transfer system operating in various transfer positions. The impedance matching problem of a WPT systems is usually caused by the misalignment of the transmitter and receiver both vertically and horizontally which alternating the mutual inductance between coils. This part will solve the problem by compress the impedance variations rather than matching the various optimal impedance for different transfer position using differential coupling method. This thesis has successfully demonstrated several novel design methods and techniques for efficient power transfer in wireless communication systems. The most challenging issues such as the nonlinear effect and low conversion efficiency have been significantly overcome by using these presented technologies. The research and knowledge in this thesis should be of great significance to the future development and have increased the boundary of this topic to a new level.
Supervisor: Zhou, Jiafeng ; Zhu, Xu Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral