A Long-Range, High-Efficiency Resonant Wireless Power Transfer via Imaginary Turn Ratio Air Voltage Transformer

This paper presents a resonant wireless power transfer method that leverages a 90-degree voltage phase shift between the transmitting and receiving coils to enhance efficiency and maximize power transfer. When the resonant coupling is achieved, the secondary coil with an adjustable capacitor forms a...

Full description

Saved in:
Bibliographic Details
Main Authors: Hsien-Chung Tang, Chun-Hao Chen, Edward-Yi Chang, Da-Jeng Yao, Wei-Hua Chieng, Jun-Ying He
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/18/6/1329
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850204038191120384
author Hsien-Chung Tang
Chun-Hao Chen
Edward-Yi Chang
Da-Jeng Yao
Wei-Hua Chieng
Jun-Ying He
author_facet Hsien-Chung Tang
Chun-Hao Chen
Edward-Yi Chang
Da-Jeng Yao
Wei-Hua Chieng
Jun-Ying He
author_sort Hsien-Chung Tang
collection DOAJ
description This paper presents a resonant wireless power transfer method that leverages a 90-degree voltage phase shift between the transmitting and receiving coils to enhance efficiency and maximize power transfer. When the resonant coupling is achieved, the secondary coil with an adjustable capacitor forms a tuned LC circuit. If the primary coil is driven at the resonant frequency of both the primary and secondary sides, the system can transmit 250W of power between the coils over a distance of 50 cm. Using a single power transmitting unit (PTU) board with multiple paralleled gallium nitride high-electron-mobility transistors (GaN HEMTs), the system achieves a maximum power transfer efficiency of 88%, highlighting the effectiveness of the design in high-efficiency, long-distance wireless power transmission. The key to the success of high-power, high-efficiency RWPT is in exhibiting the imaginary turn ratio presented on the air transformer. The imaginary turn ratio can realize the negative impedance conversion that converts the positive resistance on the power-receiving unit into a negative one, and thus, the damping of the resonance oscillation becomes negative and positively encourages more power to be delivered to the power-receiving unit (PRU) load. This paper derives the theory of the imaginary turn ratio and demonstrates the implementation of the RWPT system that exhibits the imaginary turn ratio effect.
format Article
id doaj-art-f8c73bf1626545d8a0ef8f2ff4c9afe2
institution OA Journals
issn 1996-1073
language English
publishDate 2025-03-01
publisher MDPI AG
record_format Article
series Energies
spelling doaj-art-f8c73bf1626545d8a0ef8f2ff4c9afe22025-08-20T02:11:22ZengMDPI AGEnergies1996-10732025-03-01186132910.3390/en18061329A Long-Range, High-Efficiency Resonant Wireless Power Transfer via Imaginary Turn Ratio Air Voltage TransformerHsien-Chung Tang0Chun-Hao Chen1Edward-Yi Chang2Da-Jeng Yao3Wei-Hua Chieng4Jun-Ying He5Department of Mechanical Engineering, College of Engineering, National Yang-Ming Chiao-Tung University, Hsinchu 30010, TaiwanDepartment of Material Science and Engineering, International College of Semiconductor Technology, National Yang-Ming Chiao-Tung University, Hsinchu 30010, TaiwanDepartment of Material Science and Engineering, International College of Semiconductor Technology, National Yang-Ming Chiao-Tung University, Hsinchu 30010, TaiwanDepartment of Power Mechanical Engineering, College of Engineering, National Tsing Hua University, Hsinchu 30013, TaiwanDepartment of Mechanical Engineering, College of Engineering, National Yang-Ming Chiao-Tung University, Hsinchu 30010, TaiwanDepartment of Mechanical Engineering, College of Engineering, National Yang-Ming Chiao-Tung University, Hsinchu 30010, TaiwanThis paper presents a resonant wireless power transfer method that leverages a 90-degree voltage phase shift between the transmitting and receiving coils to enhance efficiency and maximize power transfer. When the resonant coupling is achieved, the secondary coil with an adjustable capacitor forms a tuned LC circuit. If the primary coil is driven at the resonant frequency of both the primary and secondary sides, the system can transmit 250W of power between the coils over a distance of 50 cm. Using a single power transmitting unit (PTU) board with multiple paralleled gallium nitride high-electron-mobility transistors (GaN HEMTs), the system achieves a maximum power transfer efficiency of 88%, highlighting the effectiveness of the design in high-efficiency, long-distance wireless power transmission. The key to the success of high-power, high-efficiency RWPT is in exhibiting the imaginary turn ratio presented on the air transformer. The imaginary turn ratio can realize the negative impedance conversion that converts the positive resistance on the power-receiving unit into a negative one, and thus, the damping of the resonance oscillation becomes negative and positively encourages more power to be delivered to the power-receiving unit (PRU) load. This paper derives the theory of the imaginary turn ratio and demonstrates the implementation of the RWPT system that exhibits the imaginary turn ratio effect.https://www.mdpi.com/1996-1073/18/6/1329weakly coupled magnetic resonanceresonant wireless power transferlong-range WPTGaN HEMT
spellingShingle Hsien-Chung Tang
Chun-Hao Chen
Edward-Yi Chang
Da-Jeng Yao
Wei-Hua Chieng
Jun-Ying He
A Long-Range, High-Efficiency Resonant Wireless Power Transfer via Imaginary Turn Ratio Air Voltage Transformer
Energies
weakly coupled magnetic resonance
resonant wireless power transfer
long-range WPT
GaN HEMT
title A Long-Range, High-Efficiency Resonant Wireless Power Transfer via Imaginary Turn Ratio Air Voltage Transformer
title_full A Long-Range, High-Efficiency Resonant Wireless Power Transfer via Imaginary Turn Ratio Air Voltage Transformer
title_fullStr A Long-Range, High-Efficiency Resonant Wireless Power Transfer via Imaginary Turn Ratio Air Voltage Transformer
title_full_unstemmed A Long-Range, High-Efficiency Resonant Wireless Power Transfer via Imaginary Turn Ratio Air Voltage Transformer
title_short A Long-Range, High-Efficiency Resonant Wireless Power Transfer via Imaginary Turn Ratio Air Voltage Transformer
title_sort long range high efficiency resonant wireless power transfer via imaginary turn ratio air voltage transformer
topic weakly coupled magnetic resonance
resonant wireless power transfer
long-range WPT
GaN HEMT
url https://www.mdpi.com/1996-1073/18/6/1329
work_keys_str_mv AT hsienchungtang alongrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT chunhaochen alongrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT edwardyichang alongrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT dajengyao alongrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT weihuachieng alongrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT junyinghe alongrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT hsienchungtang longrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT chunhaochen longrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT edwardyichang longrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT dajengyao longrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT weihuachieng longrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer
AT junyinghe longrangehighefficiencyresonantwirelesspowertransferviaimaginaryturnratioairvoltagetransformer