Optimization of Wireless Power
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Today, the limit of wireless devices lays in the way they are powered. Imagine a device that doesn’t need a charger or even a battery, which instead gets the power wirelessly over the air. To make such a device possible the transfer distance of currently known systems have to be increased. That will be the aim of this thesis, to investigate how to increase the transfer distance of a wireless power system, WPS, purposed to charge low power electronic devices. In order for the system to be usable certain design limits are set to restricts the size of the coils, flat spiral coils with diameter < 90mm and wire diameter < 2mm, and thereby also narrowing the scope of the thesis.This thesis starts with a presentation of the theoretical framework behind wireless power, including techniques for modeling a complete system. The framework is then broken down to its basic components which generates expressions with geometrical and material properties as variables. These expressions are implemented in Matlab creat- ing a simulator, which finds optimal values of geometrical and material properties that maximizes the transfer distance.The simulator is set up and ran for each system, 2, 3 and 4 coils, this because each system behaves differently and all have some desirable properties. The findings are implemented in Comsol which provides verification and illustrates the electromagnetic fields that are generated. The results from Comsol and Matlab are similar and shows that a 2-coil system can transfer power with 40% efficiency over a distance of ≈ 150mm. While 3- and 4-coil systems significantly improve the transfer distance and can transfer power with the same efficiency over a distance of ≈ 350mm.As a last step were WPS’s built using the findings from the simulations. The coils were made according to the optimal parameters and capacitors were added to tune them to the same resonance frequency. An E-class amplifier was designed and built to excite the transmitting coil in the real system. The measurements made are the power delivered to the amplifier and the power delivered to the load. From that the efficiency of the complete system can be calculated. The measurements made in this thesis don’t hold up to the simulations in the sense of transfer distance. The main reasons for that is that the amplifier is included in the measured PTE and not in the simulations and that the coils are not perfectly built or tuned.
Place, publisher, year, edition, pages
2013. , 52 p.
Technology, Wireless Power
IdentifiersURN: urn:nbn:se:ltu:diva-58486Local ID: f11daa97-018c-4402-87fd-d6572923b505OAI: oai:DiVA.org:ltu-58486DiVA: diva2:1031874
Subject / course
Student thesis, at least 30 credits
Engineering Physics and Electrical Engineering, master's level
Validerat; 20131010 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved