Wireless Power Transfer with Class E Power Amplifier and Magnetic Field Repeater

Wireless Power Transfer is the future alternative to replace overhead and underground transmission methods in delivering electrical power. The attention given to this technology has been increasing tremendously after MIT introduced Magnetic Resonance Coupling which utilizes magnetic resonance to deliver power wirelessly. There is great potential to research on this area as it can deliver power to unreachable areas and it will be the method of transmitting electrical power in the future. In this project, a combination of Class E power amplifier and magnetic field repeater is proposed with the aim of enhancing the transmission power and distance. Besides that, Litz wire is used as the material for transmitter and receiver coil in order to reduce the skin effect because the ac resistance will increase drastically when the system is operating in high frequency

Efficient wireless power transfer via magnetic resonance coupling using automated impedance matching circuit

In this paper, an automated impedance matching circuit is proposed to match the impedance of the transmit and receive resonators for optimum wireless power transfer (WPT). This is achieved using a 2D open-circuited spiral antenna with magnetic resonance coupling in the low-frequency ISM band at 13.56 MHz. The proposed WPT can be adopted for a wide range of commercial applications, from electric vehicles to consumer electronics, such as tablets and smartphones. The results confirm a power transfer efficiency between the transmit and receive resonant circuits of 92%, with this efficiency being sensitive to the degree of coupling between the coupled pair of resonators

Efficient Wireless Power Transfer via Magnetic Resonance Coupling Using Automated Impedance Matching Circuit

In this paper, an automated impedance matching circuit is proposed to match the impedance of the transmit and receive resonators for optimum wireless power transfer (WPT). This is achieved using a 2D open-circuited spiral antenna with magnetic resonance coupling in the low-frequency ISM band at 13.56 MHz. The proposed WPT can be adopted for a wide range of commercial applications, from electric vehicles to consumer electronics, such as tablets and smartphones. The results confirm a power transfer efficiency between the transmit and receive resonant circuits of 92%, with this efficiency being sensitive to the degree of coupling between the coupled pair of resonators

The impact of Nodes Distance on Wireless Energy Transfer System

Wireless energy transfer (WET) reemerges as the method for transmitting electric power without the necessity to deal with cable losses and an aesthetically pleasing environment. The problem with WET is how to maintain magnetic induction as the distance gets further. This paper investigates the impact of nodes distance on the WET system. The experimental results show that the most effective distance among transmitter, nodes, and receiver are 4 cm. The measurement is taken with and without load. The without load application give that for node 1; the results are 6 V, 110 mA, and 2.85 mT for voltage, current, and magnetic flux, respectively. At the application of 2 nodes, the voltage is 6.8 V, the current is 0.124 mA, and the magnetic flux is 3.83 mT, and at three nodes installation, it is 7 V, 134 mA, and 3.83 mT. During the application of 3-Watt and 5-Watt lamp, at 4 cm distance, the power received is 1.66 W and 3.66 W at 3-Watt and 5-Watt lamp for one node, 1.84 W, and 3.84 for two nodes, and 1.93 W and 3.93 for three nodes. The experimental results show that the transmitted signal can be prolonged by installing nodes. Even though this study shows that 4 cm is the most effective, it is possible to increase up to 20 cm to power a 3-Watt lamp and 5-Watt lamp

Review study of tunable intermediate-resonator for selective wireless power transfer system over various distances

This paper presents a selective magnetic resonant wireless power transfer (WPT) system, consisting of a transmitter (TX), a tunable intermediate-resonator, and a receiver (RX). In the proposed WPT system, the tunable intermediate-resonator can be either a relay resonator or an intermediate-RX by varying its variable resistance, demonstrating the flexibility of the intermediate resonator to be used for different topologies and applications. This flexibility will enable the proposed WPT system to transfer maximum energy efficiency to various distances between the TX and the RX, to longer distances for the WPT relay system and to shorter distances for the intermediate-RX system. In this case, the WPT intermediate-RX system has a larger power transfer efficiency than the WPT relay system.Postprint (published version

Radio wave propagation studies through modern windows

Abstract. It is a growing trend in the modern housing construction especially in northern parts of Europe and America to use modern windows with selective glasses in order to achieve the adequate thermal isolation. The idea is to conserve the energy and discourage the excess use of it following the guidelines of European commission, which aims to achieve zero energy buildings by 2020. Even though the use of such windows do address the energy issue at hand, but on the other hand they cause problems to the radio wave propagation through these windows. The reason for this is the use of metallic coating made of titanium oxide or silver oxide in general on these windows because of their good properties to provide thermal isolation, but are susceptible to deterioration of radio wave propagation through them. Various solutions to this problem have been addressed in this thesis along with their tradeoffs. The previous and current research being carried out to address this issue also have been discussed thoroughly including the research that worked as the motivation to pursue this issue. Amongst others, one solution is the use of passive repeater to achieve the power gain which have been focused on. A prototype repeater antenna developed earlier at CWC and tested through measurements addresses the problem considerably well. Measurements were taken at EMC chamber, University of Oulu, within the frequency range of 700 MHz to 10 GHz, and the results have been compared and analyzed in this thesis. According to our findings, the repeater antenna under the test has shown promising results. In the future work, the proposed repeater can be tested in real life scenarios and its performance can be analyzed within the real life environmental constraints

Analysis of Antenna Designs for the Maximum Power Transmission

Since Nikola Tesla discovered wireless power transmission, it has become a very interesting topic of study in the antennas and wireless propagation community. Various aspects and applications for wireless power transmission are studied today, a few of which are investigated in this work. First, various antenna geometries are analyzed for radiative near-field wireless power transfer in terms of electrical field strength. It is determined that the meander antenna is ideal for maximum power transfer in its radiative near-field region, contrary to its far-field behavior. Next, in the application of radio frequency identification, a directive, UHF RFID tag antenna is designed for pavement embedded applications. The antenna covers 72% of the US required bandwidth (902 – 928 MHz) in measurement and has maximum directivity and read range of 7.38 dBi and 14.2ft (4.3 m), respectively. Although the transmitter and receiver antennas\u27 designs are essential parts of the wireless system, power loss to the wireless channel is another critical factor to consider in ensuring the receiver antenna receives the maximum power. Friis transmission equation is studied in detail, and a section of the Georgia Southern University campus is considered for full cellular coverage in the GSM frequency range. Additionally, using the genetic algorithm in parallel, the optimal position for a 60-GHz wireless router is determined to obtain maximum WIFI coverage in a specific house. Finally, the design procedure for a size-reduced, 15-element Yagi antenna is discussed. A comprehensive comparison is conducted demonstrating the importance of the antenna design, with its similar performance to the full-sized Yagi antenna, while its elements are reduced by 45%