Comparative Analysis of Two- and Three-Coil WPT Systems Based on Transmission Efficiency
It is obvious that the conventional two-coil wireless power transfer (WPT) system has a short power transmission distance, which is determined by system parameters such as the loaded Q of the resonators and the coupling coefficient. There have been many attempts to improve the power transfer efficie...
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doaj-e78c885fc0034ee1b91ad0266f009b662021-03-29T23:19:01ZengIEEEIEEE Access2169-35362019-01-01715196215197010.1109/ACCESS.2019.29470938866730Comparative Analysis of Two- and Three-Coil WPT Systems Based on Transmission EfficiencyDong-Wook Seo0https://orcid.org/0000-0001-9449-7772Department of Radio Communication Engineering, Korea Maritime and Ocean University, Busan, South KoreaIt is obvious that the conventional two-coil wireless power transfer (WPT) system has a short power transmission distance, which is determined by system parameters such as the loaded Q of the resonators and the coupling coefficient. There have been many attempts to improve the power transfer efficiency (PTE) or transmission distance. A typical approach is to use multiple coils like a three- or four-coil WPT system. In this paper, we propose a new method to obtain the PTE of a multi-coil WPT system based on the scattering parameter and impedance parameter. Also, we compare the two- and three-coil WPT systems in terms of their transmission efficiency rather than their system energy efficiency. For high transmission efficiency, we determined that the three-coil WPT system should have a symmetric structure and the coupling coefficient between the transmitting and receiving coils has to be as zero as possible. Additionally, we found that 1/√3 of the conventional critical coupling is the boundary coupling coefficient at which the two- and three-coil WPT systems have the same transmission efficiency. We successfully verified these theoretical analyses by implementing two- and three-coil WPT systems at the operating frequency of 6.78 MHz and measuring their transmission efficiency and spectra.https://ieeexplore.ieee.org/document/8866730/Power transfer efficiencythree-coil WPT systemtransmission efficiencytwo-coil WPT systemwireless chargingwireless power transfer |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Dong-Wook Seo |
spellingShingle |
Dong-Wook Seo Comparative Analysis of Two- and Three-Coil WPT Systems Based on Transmission Efficiency IEEE Access Power transfer efficiency three-coil WPT system transmission efficiency two-coil WPT system wireless charging wireless power transfer |
author_facet |
Dong-Wook Seo |
author_sort |
Dong-Wook Seo |
title |
Comparative Analysis of Two- and Three-Coil WPT Systems Based on Transmission Efficiency |
title_short |
Comparative Analysis of Two- and Three-Coil WPT Systems Based on Transmission Efficiency |
title_full |
Comparative Analysis of Two- and Three-Coil WPT Systems Based on Transmission Efficiency |
title_fullStr |
Comparative Analysis of Two- and Three-Coil WPT Systems Based on Transmission Efficiency |
title_full_unstemmed |
Comparative Analysis of Two- and Three-Coil WPT Systems Based on Transmission Efficiency |
title_sort |
comparative analysis of two- and three-coil wpt systems based on transmission efficiency |
publisher |
IEEE |
series |
IEEE Access |
issn |
2169-3536 |
publishDate |
2019-01-01 |
description |
It is obvious that the conventional two-coil wireless power transfer (WPT) system has a short power transmission distance, which is determined by system parameters such as the loaded Q of the resonators and the coupling coefficient. There have been many attempts to improve the power transfer efficiency (PTE) or transmission distance. A typical approach is to use multiple coils like a three- or four-coil WPT system. In this paper, we propose a new method to obtain the PTE of a multi-coil WPT system based on the scattering parameter and impedance parameter. Also, we compare the two- and three-coil WPT systems in terms of their transmission efficiency rather than their system energy efficiency. For high transmission efficiency, we determined that the three-coil WPT system should have a symmetric structure and the coupling coefficient between the transmitting and receiving coils has to be as zero as possible. Additionally, we found that 1/√3 of the conventional critical coupling is the boundary coupling coefficient at which the two- and three-coil WPT systems have the same transmission efficiency. We successfully verified these theoretical analyses by implementing two- and three-coil WPT systems at the operating frequency of 6.78 MHz and measuring their transmission efficiency and spectra. |
topic |
Power transfer efficiency three-coil WPT system transmission efficiency two-coil WPT system wireless charging wireless power transfer |
url |
https://ieeexplore.ieee.org/document/8866730/ |
work_keys_str_mv |
AT dongwookseo comparativeanalysisoftwoandthreecoilwptsystemsbasedontransmissionefficiency |
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