scholarly journals GaN-Based Dual-Mode Wireless Power Transfer Using Multifrequency Programmed Pulse Width Modulation

2017 ◽  
Vol 64 (11) ◽  
pp. 9165-9176 ◽  
Author(s):  
Chongwen Zhao ◽  
Daniel Costinett
Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3656
Author(s):  
Li-Chuan Tang ◽  
Shyr-Long Jeng ◽  
Edward-Yi Chang ◽  
Wei-Hua Chieng

In this paper, we develop a variable-frequency pulse width modulation (VFPWM) circuit for input control of 6.78-MHz resonant wireless power transfer (WPT) systems. The zero-voltage switching control relies on the adjustments of both duty cycle and switching frequency for the class-E amplifier used in the WPT as the power transmission unit. High-frequency pulse wave modulation integrated circuits exist, but some have insufficiently high frequency or unfavorable resolution for duty cycle tuning. The novelty of this work is the VFPWM circuit design that we put together. A voltage-controlled oscillator (VCO) of radio frequency and capacitor-coupled difference amplifiers are used to simultaneously perform the frequency and duty cycle tuning required in resonant WPT applications. Different circuit topologies of VFPWM are compared analytically and numerically. The most favorable circuit topology, enabling independent control of the frequency and duty cycle, is employed in experiments. The experimental results demonstrate the validity of the novel VFPWM, which is capable of operating at 6.78 MHz and has a duty ratio adjustable from 20% to 45% of the range applicable in the resonant WPT applications.


Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8245
Author(s):  
Emmanuel Ahene ◽  
Mark Ofori-Oduro ◽  
Frimpong Twum ◽  
Joojo Walker ◽  
Yaw Marfo Missah

Chaos theory and its extension into cryptography has generated significant applications in industrial mixing, pulse width modulation and in electric compaction. Likewise, it has merited applications in authentication mechanisms for wireless power transfer systems. Wireless power transfer (WPT) via resonant inductive coupling mechanism enables the charging of electronic devices devoid of cords and wires. In practice, the key to certified charging requires the use of an authentication protocol between a transmitter (charger) and receiver (smartphone/some device). Via the protocol, a safe level and appropriate charging power can be harvested from a charger. Devoid of an efficient authentication protocol, a malicious charger may fry the circuit board of a receiver or cause a permanent damage to the device. In this regard, we first propose a chaos-based key exchange authentication protocol and analyze its robustness in terms of security and computational performance. Secondly, we theoretically demonstrate how the protocol can be applied to WPT systems for the purposes of charger to receiver authentication. Finally, we present insightful research problems that are relevant for future research in this paradigm.


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