scholarly journals Optimization for Compact and High Output LED-Based Optical Wireless Power Transmission System

Photonics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Mingzhi Zhao ◽  
Tomoyuki Miyamoto
Keyword(s):  
Electromagnetic Interference ◽  
Power Transmission ◽  
Light Emitting Diode ◽  
Transmission Efficiency ◽  
Optical Wireless ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Long Distance ◽  
Transmission Distance ◽  
Led Array

Optical wireless power transmission (OWPT) is a technology that supplies energy remotely. Due to the great advantages of long transmission distances, high directionality, no electromagnetic interference noise, and loose safety regulations, light emitting diode (LED) based OWPT systems become appropriate candidates for powering various applications, especially for the Internet of things (IoT). In this paper, improved LED-OWPT systems are proposed based on a collimation scheme for optimizing the system dimension and output. In a single LED configuration, the system dimension is compressed by 46% while the high transmission efficiency is maintained. As for the LED-array system, the dimension is compressed by 56%, and the output is enhanced by 40%. In the experiment, a high electricity output of 532 mW is achieved at 1 m transmission distance. In addition, the effect of misalignment between LED and lens and the potential of long-distance transmission are clarified in the LED-array OWPT system.

Compensating Resonant Frequency via Adjusting Adjustable Coil Automatically

2019 ◽  
Vol 12 (5) ◽  
pp. 432-438
Author(s):  
Jin Xu ◽  
Yuting Zhao
Keyword(s):  
Resonant Frequency ◽  
Power Transmission ◽  
Reference Value ◽  
Transmission Efficiency ◽  
Theoretical Research ◽  
Future Research ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Resonant Coupling ◽  
Transmission Distance

Background: Detuning is the main problem that affects the efficiency and transmission distance of the resonant coupling Wireless Power Transmission (WPT). The distance of load and the offset of the load position could cause serious detuning. Methods: This paper presents an adjustable coil in which inductance can be adjusted. Then a model of WPT was established that could compensate resonant frequency automatically using the adjustable coil. Next, the relationship between the primary resonant frequency and the transmission efficiency is analyzed from the circuit. The analysis proved that the design of the adjustable coil could improve the transmission efficiency of the WPT system. Finally, a prototype of WPT system was built. Results: The experimental results showed that WPT system with adjustable coil can improve the transmission efficiency which proves the theoretical research. At the same time, it has essential reference value for the future research of WPT. Conclusion: In this paper, aiming at the system detuning caused by some other factors, such as the position shift of the load during the wireless power transmission, an adjustable coil is proposed.

scholarly journals Design of High-Power High-Efficiency Wireless Charging Coils for EVs with MnZn Ferrite Bricks

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yuyu Zhu ◽  
Zuming Wang ◽  
Xin Cao ◽  
Li Wu
Keyword(s):  
High Power ◽  
High Efficiency ◽  
Power Transmission ◽  
Transmission Efficiency ◽  
Wireless Transmission ◽  
Wireless Charging ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Quality Factors ◽  
Transmission Distance

In wireless power transmission systems, the inductance, equivalent resistance, and quality factors of the coils are the main factors that influence the system’s transmission efficiency. When designing high-power wireless charging coils for electric vehicles (EVs), ferrite bricks that increase magnetic flux can be selected to increase the self-inductance of the coils, improving the wireless transmission distance and transmission efficiency. In this paper, the effects of the ferrite bricks, the size of the coils, the charging distance, and many other factors in real applications have been extensively studied. After theoretical analysis and simulation, the wireless transmission system has been fabricated and measured. The measured and simulated results are in good agreement. High-power high-efficiency wireless power transmission has been achieved for EVs compared with many other previous literatures.

scholarly journals Wireless power transfer system based on frequency and impedance matching hybrid adjustment against system detuning

2021 ◽  
Vol 2108 (1) ◽  
pp. 012035
Author(s):  
Zhengnan Yuan ◽  
Pengcheng Fu ◽  
Guangshuai Lu ◽  
Pengfei Cao
Keyword(s):  
Magnetic Resonance ◽  
Power Transmission ◽  
Impedance Matching ◽  
Transmission Efficiency ◽  
Resonant Circuit ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Transmission Distance ◽  
Magnetic Resonance Coupling ◽  
Resonance Coupling

Abstract System detuning caused by a variation in the distance between the transmitting and receiving terminals can greatly reduce the transmission power and efficiency of a magnetic resonance-coupled wireless power transmission (WPT) system, which limits the WPT application scope. This paper proposes a magnetic resonance coupling wireless power transmission system, which is based on jointly and continuously adjustable frequency compensation (CAFC) and two-transistor-controlled variable capacitor circuits (TCVCs). Therefore, this system can reach the resonant state by using CAFC and two-TCVCs when the transmission distance is changed. The proposed system can adaptively adjust combinations of the operating frequency and equivalent compensation capacitor’s capacitance to achieve impedance matching avoiding the phase difference caused by the imaginary part of the impedance, thus maintaining stable transmission efficiency under the condition of transmission distance variation. Compared to the traditional magnetic coupled resonant circuit based on impedance matching or variable resonant frequency, the proposed system achieves higher efficiency and stability and dynamic distance adaptation.

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