scholarly journals Analysis and Optimization of Asymmetric Wireless Power Transfer in Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zijian Tian ◽  
Dairong Liu ◽  
Wei Chen ◽  
Wenqing Wang ◽  
Shan Pan ◽  
...  

With the rapid development of the Internet of things (IoT) technology, the application of IoT has been expanded greatly, and the disadvantages of the traditional battery power supply have become increasingly prominent. The power supply mode limits the development of the concrete structural health monitoring network. And the application of magnetic resonance coupled wireless power transfer technology can solve the problem of power supply to sensors embedded in concrete. The corrected transmission efficiency considering the concrete conductivity is proposed which establishes the relationship between the electromagnetic field and the circuit model. And the field-circuit coupled model of asymmetric wireless power transfer system in concrete is developed. The effects of radial offset and axial dislocation on the transmission efficiency at different concrete conductivity are further analyzed. The relationship between the resonant frequency and the transmission efficiency in different concrete conductivity is analyzed, and an optimization scheme is proposed to improve the transmission efficiency. Finally, the experimental setups are established, and the theoretical analysis is verified. The conclusions cannot only break through the bottleneck of the scale of the concrete structural health monitoring network but also further releases the application potential of IoT.

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3803
Author(s):  
Chan-Mi Song ◽  
Hong-Jun Lim ◽  
Son Trinh-Van ◽  
Kang-Yoon Lee ◽  
Youngoo Yang ◽  
...  

In this paper, a dual-band RF wireless power transfer (WPT) system with a shared-aperture dual-band Tx array antenna for 2.4 and 5.8 GHz is proposed. The final configuration of the Tx array, which is made up of 2.4 GHz right-handed circular polarization (RHCP) patches and 5.8 GHz RHCP patches, is derived from the optimization of 2.4 and 5.8 GHz thinned arrays, ultimately to achieve high transmission efficiency for various WPT scenarios. The dual-band RF WPT Tx system including the Tx array antenna and a Tx module is implemented, and Rx antennas with a 2.4 GHz patch, a 5.8 GHz patch, and a dual-band (2.4 and 5.8 GHz) patch are developed. To validate the proposed dual-band RF WPT system, WPT experiments using a single band and dual bands were conducted. When transmitting RF wireless power on a single frequency (either 2.482 GHz or 5.73 GHz), the received power according to the distance between the Tx and Rx and the position of the Rx was measured. When the distance was varied from 1 m to 3.9 m and the transmitted power was 40 dBm, the received power value at 2.482 GHz and 5.73 GHz were measured and found to be 24.75–13.5 dBm (WPT efficiency = 2.985–0.224%) and 19.25–6.8 dBm (WPT efficiency = 0.841–0.050%), respectively. The measured results were in good agreement with the calculated results, and it is revealed that the transmission efficiency when wireless power is transmitted via beam-focusing increases more than that with conventional beam-forming. Furthermore, the dual-band WPT experiment proves that 2.482 GHz beam and 5.73 GHz beams can be formed individually and that their wireless power can be transmitted to a dual-band Rx or two different Rx.


Author(s):  
Kazuya Yamaguchi

<pre>This paper derives an expression of efficiency of wireless power transfer on a situation that there are two devices towards one AC power supply. The interaction between a power supply and load is paid attention on a conventional wireless power transfer system, in contrast, the interaction between loads must be taken account of on the situation too. This is attributed to a possibility that a load disturbs the energy transmitted from a power supply to another load. Moreover each load needs different frequency of power supply for the ideal transfer since they have different natural frequencies on many situations. This paper models a circumstance that there are a power supply and two loads with a state space equation, and proposes how to decide a frequency of power supply to realize efficient transfer for each load.</pre>


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