scholarly journals Optimal resonant frequency analysis for underground wireless power transfer with metal tube interference

AIP Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 105109
Author(s):  
Yu Xu ◽  
Qili Chen ◽  
Yongquan Zhang ◽  
Bo Li ◽  
Huiming Tang
Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 415
Author(s):  
Haiyue Wang ◽  
Lianwen Deng ◽  
Heng Luo ◽  
Junsa Du ◽  
Daohan Zhou ◽  
...  

The microwave wireless power transfer (MWPT) technology has found a variety of applications in consumer electronics, medical implants and sensor networks. Here, instead of a magnetic resonant coupling wireless power transfer (MRCWPT) system, a novel MWPT system based on a frequency reconfigurable (covering the S-band and C-band) microstrip patch antenna array is proposed for the first time. By switching the bias voltage-dependent capacitance value of the varactor diode between the larger main microstrip patch and the smaller side microstrip patch, the working frequency band of the MWPT system can be switched between the S-band and the C-band. Specifically, the operated frequencies of the antenna array vary continuously within a wide range from 3.41 to 3.96 GHz and 5.7 to 6.3 GHz. For the adjustable range of frequencies, the return loss of the antenna array is less than −15 dB at the resonant frequency. The gain of the frequency reconfigurable antenna array is above 6 dBi at different working frequencies. Simulation results verified by experimental results have shown that power transfer efficiency (PTE) of the MWPT system stays above 20% at different frequencies. Also, when the antenna array works at the resonant frequency of 3.64 GHz, the PTE of the MWPT system is 25%, 20.5%, and 10.3% at the distances of 20 mm, 40 mm, and 80 mm, respectively. The MWPT system can be used to power the receiver at different frequencies, which has great application prospects and market demand opportunities.


2016 ◽  
Vol 3 (1) ◽  
pp. 9-14
Author(s):  
Nurcan Keskin ◽  
Huaping Liu

Power transfer efficiency in loosely coupled inductive systems can be enhanced by resonance. Primary and secondary can be tuned to same resonant frequency. In this paper, MOSFET-based Varactors and switchable capacitors are used for re-tuning of such a system at 13.56 MHz. This is achieved either using each cap structure alone or as a hybrid model. These techniques are designed for 13.56 MHz wireless power transfer system.


Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1303
Author(s):  
Do-Hyun Kim ◽  
Min-Soo Kim ◽  
Hee-Je Kim

The wireless power transfer (WPT) system has attracted attention for energy transmission without physical contact. However, a WPT system has low coupling condition because of a big air gap between transmitter and receiver coils. The low coupling condition has a high leakage inductance. To overcome this problem, we design a proposed system for WPT using series-series (S-S) topology of one resonant circuit. To obtain the higher efficiency power conversion of the WPT system, it has to operate the resonant frequency in the zero phase angle (ZPA) point even under mutual coefficient and load variation. Therefore, we propose the resonant frequency tracking algorithm to operate ZPA point based on the second order generalized integrator-frequency locked loop (SOGI-FLL) method. This proposed frequency-tracking algorithm can estimate ZPA point by changing switching frequency. We can reduce the switching loss with this proposed algorithm and improve the low conversion efficiency of the WPT system. The performance of the proposed frequency-tracking algorithm is automatically verified through various coupling coefficients and the load variation.


Author(s):  
Kazuya Yamaguchi ◽  
Takuya Hirata ◽  
Ichijo Hodaka

A wireless power transfer (WPT) circuit is composed of a transmitting circuit with an AC power supply and a receiving circuit with a load, and the circuits are wirelessly connected each other. Then a designer chooses the wave form of the AC power supply. Many papers about WPT adopt a sinusoidal wave as the input. The frequency of the sinusoidal wave is generally determined to the resonant frequency of the circuit for high power transfer. Since the number of circuit elements in the power supply to generate a square wave is much less than that of a sinusoidal wave, WPT with a square wave input should be treated. In fact, some papers about WPT adopt a square wave as the input, and adjust the frequency of the square wave to the resonant frequency of the circuit. In this paper, we examine how the frequency of a square wave input affects power and efficiency of WPT circuits, and propose a procedure how to determine the frequency of the input to improve power and efficiency. Finally we discuss which wave should be adopted as an input and how the frequency of the input should be determined, regardless of whether resonant phenomena occur or not.


Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1912 ◽  
Author(s):  
Ben Minnaert ◽  
Franco Mastri ◽  
Nobby Stevens ◽  
Alessandra Costanzo ◽  
Mauro Mongiardo

Capacitive wireless power transfer can be realized by mutually coupled capacitors operating at a common resonant frequency. An optimal load exists that maximizes either the efficiency or the power transfer to the load. In this work, we utilize the frequency bifurcation effect to propose a frequency agile mode that allows for a nearly coupling-independent regime. We analytically determine the operating conditions of the coupling-independent mode based on the different system gains. In this way, we obtain a solution that achieves nearly constant efficiency and power transfer, even at varying coupling. We compare our results to inductive wireless power transfer where a perfect coupling-independent mode is achievable.


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