High Q-factor WPT system with negative impedance converter

Yoon, Sehwa; Kim, Tae-Hyung; Yook, Jong‐Gwan; Yun, Gi-Ho; Lee, Woongyong

doi:10.1109/wpt.2017.7953801

Cited by 9 publications

(7 citation statements)

References 11 publications

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“…The NIC employs active components, such as operational amplifier and a bipolar junction transistor (BJT). The negative impedance is determined for a loaded impedance or a ratio of the feedback impedance for a capacitor, inductor, and resistor [27]- [33]. The transistorized NICs proposed by Linvill [28] are categorized according to the voltage and current inversions, floating and grounded connections, open-and short-circuit stability, and open-and short-circuit instability [28]- [33].…”

Section: B Non-foster Circuitmentioning

confidence: 99%

“…They operated a 60-W light bulb by using coils 60 cm in diameter at a distance of 2 m. A power transfer efficiency (PTE) of approximately 45% was observed at the resonant frequency of 9.9 MHz [1]. Various studies on the WPT system using the MRC method have been performed, including effects of the rotation as well as misalignment of the receiving coil [2]- [4], meta-material [5], [6], domino structure [7], [8], optimization of the coil design [9]- [11], the effects of the ferrite and conductor [14]- [16], analysis of the WPT system [19]- [26], and WPT system with negative impedance converter (NIC) [27].…”

Section: Introductionmentioning

confidence: 99%

“…The PTE is improved at various distances owing to the increased Q-factor of the coil. However, the drawback of this work is that Op-Amp does not use input current due to the infinity of input impedance [27]. Hence, the NIC with Op-Amp is very difficult to apply the practical applications because both the voltage and current of the RF signal power should be used for wireless charging as well as the power is used for relatively low level.…”

Section: Introductionmentioning

confidence: 99%

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Highly Efficient WPT System With Negative Impedance Converter for Q-factor Improvement

et al. 2019

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A negative impedance converter (NIC) has been combined with a wireless power transfer (WPT) system to maximize the system efficiency based on non-foster theory. The NIC is composed of transistor, voltage divider, capacitor, and inductor for impedance matching, and resonant circuit operating at 6.78 MHz. The desired negative impedance can be controlled by tunable impedance in the NIC. In this paper, the loss of the transmitting coil is reduced to 0.1 , yielding a quality factor of 7,050, which is 19.1 times higher than that of the conventional coil. The WPT system with the NIC provides high power transfer efficiency (PTE) at various transmission distances. The experimental results are improved from 64% to 96% and from 5% to 55% at the transmission distances of 50 and 200 mm, respectively. Furthermore, the PTE is enhanced from 38% to 87% and from 2% to 38% at the diagonal misalignment distance of 0 and 150 mm, respectively, at a transmission distance of 100 mm. The proposed technology for increasing the receiving power in the receiving coil with a higher PTE can be utilized for numerous applications in the industrial, scientific, and medical band, with a restricted radio frequency power on the transmitter side.

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Section: B Non-foster Circuitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Highly Efficient WPT System With Negative Impedance Converter for Q-factor Improvement

et al. 2019

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“…Until now, investigations on wireless power transfer technology have mainly focused on the design and optimization of the magnetic coupling structure [10][11][12][13][14], compensation topology [15][16][17][18][19][20][21][22][23], and control algorithm [24,25]. In addition to academic research, wireless power transfer technology has been commercialized.…”

Section: Introductionmentioning

confidence: 99%

Design and Optimization of a Wireless Power Transfer System with a High Voltage Transfer Ratio

et al. 2022

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With the development of the logistics industry, low-voltage systems, such as intelligent logistics vehicles, have also started to propose application scenarios for wireless power transfer systems. As most logistics vehicles use lithium batteries for energy supply, the wireless charging system has to adapt to the charging characteristic curve of lithium batteries. In this paper, a dual-transmitter single-receiver compound resonant compensation topology with a high voltage ratio is proposed, and a corresponding magnetic coupler is designed and optimized through finite element analysis, which guarantees adaptive output curves according to the working state. A 1 kW experimental platform is established to verify the theoretical analysis, which realizes a high voltage transformation ratio with 90.3% efficiency. Throughout the whole charging process, the output curve agrees with the charging profile of the lithium battery, which can greatly extend the service life of lithium batteries.

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“…In [18], the coils of quality factor up to 1000 were employed to achieve PTE of 10% when the transmission distances is about nine times than the radius of the coils. In [19], a negative impedance converter was applied in the receiving coil to significantly enhance Q ‐factor from 76 to 1640, which contributed to the high PTE of 29%. For a high Q ‐factor, the working frequencies for the WPT systems are typically in several hundreds of kilohertz, even about ten megahertzs [20].…”

Section: Introductionmentioning

confidence: 99%

A critical review of metamaterial in wireless power transfer system

Chen

Zeng

et al. 2021

IET Power Electronics

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Wireless power transfer (WPT) is a promising charging method without physical contact for the electronic products energy supply. However, low transfer efficiency, short transmission distance, as well as the electromagnetic (EM) leakage are commonly main bottlenecks of the WPT technology in the practical applications. The electromagnetic metamaterials (EMMMs) used in WPT system have opened up a brand-new approach for better transfer properties and EM shielding. This paper is intended to provide an overview of the current studies and breakthroughs of the WPT system based on EMMMs. First, we demonstrate the fundamentals of the WPT based on the magnetic resonant coupling. Then, various key considerations of the EMMMs, such as working mechanisms, fabrications have been taken into accounted in detail. Moreover, the applications of EMMM in WPT systems are elaborated. Finally, the technical challenges in connection with working frequency and design miniaturization are investigated in this paper. This novel interdisciplinary technology shows important meanings on the extensive application of energy transmission in the future.

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High Q-factor WPT system with negative impedance converter

Cited by 9 publications

References 11 publications

Highly Efficient WPT System With Negative Impedance Converter for Q-factor Improvement

Highly Efficient WPT System With Negative Impedance Converter for Q-factor Improvement

Design and Optimization of a Wireless Power Transfer System with a High Voltage Transfer Ratio

A critical review of metamaterial in wireless power transfer system

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