The relay effect on wireless power transfer using witricity

Zhang, Fei; Hackworth, Steven A.; Fu, Weinong; Sun, Mingui

doi:10.1109/cefc.2010.5481512

Cited by 45 publications

(26 citation statements)

References 2 publications

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“…In [25], a metamaterial with a relative permeability equal to −1 is used to increase the transmission efficiency for a given distance. In [26], additional "relay" resonators are placed between the transmitter and receiver resonators in a domino arrangement in order to increase the efficiency effectively.…”

Section: Introductionmentioning

confidence: 99%

General Analysis on the Use of Tesla's Resonators in Domino Forms for Wireless Power Transfer

Zhong

Lee

Hui

2013

IEEE Trans. Ind. Electron.

318

158

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In this paper, we present a brief overview of historical developments of wireless power and an analysis on the use of Tesla's resonators in domino forms for wireless power transfer. Relay resonators are spaced between the transmitter and receiver coils with the objectives of maximizing energy efficiency and increasing the overall transmission distance between the power source and the load. Analytical expressions for the optimal load and maximum efficiency at resonance frequency are derived. These equations are verified with practical measurements obtained from both coaxial and noncoaxial domino resonator systems. To avoid the use of high operating frequency for wireless power transfer in previous related research, the technique presented here can be used at submegahertz operation so as to minimize the power loss in both the power supply and the output stage. We demonstrated both theoretically and practically that unequal spacing for the coaxial straight domino systems has better efficiency performance than the equal-spacing method. Also, the flexibility of using resonators in various domino forms is demonstrated.Index Terms-Domino resonator system, maximum efficiency operation, relay resonator, wireless power transfer (WPT).

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Section: Introductionmentioning

confidence: 99%

General Analysis on the Use of Tesla's Resonators in Domino Forms for Wireless Power Transfer

Zhong

Lee

Hui

2013

IEEE Trans. Ind. Electron.

318

158

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“…Based on the new developments in improving the transfer distance, a new planar design would be able to charge the devices on desks and tables. To address the poor transfer efficiency defects of a two-coil energy transfer mechanism, as considered in [20,23,59], midrange WPT techniques, such as relay resonators [60,61] (Figure 4a), four coils [15,[62][63][64] (Figure 4b), U coils [65] (Figure 4c), domino coils [56,66] (Figure 4d), array coils [67] (Figure 4e), and dipole coils [68] (Figure 4f) are proposed in previous studies and fused into future planar WPT chargers with increased distances or air gaps. Based on these studies, the transfer distances were 20, 60, 100, 180 (for seven resonator coils), 20, and 500 cm ( [60], [15], [65], [66], [67] and [68], respectively).…”

Section: Transfer Distancementioning

confidence: 99%

Opportunities and Challenges for Near-Field Wireless Power Transfer: A Review

et al. 2017

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Abstract:Traditional power supply cords have become less important because they prevent large-scale utilization and mobility. In addition, the use of batteries as a substitute for power cords is not an optimal solution because batteries have a short lifetime, thereby increasing the cost, weight, and ecological footprint of the hardware implementation. Their recharging or replacement is impractical and incurs operational costs. Recent progress has allowed electromagnetic wave energy to be transferred from power sources (i.e., transmitters) to destinations (i.e., receivers) wirelessly, the so-called wireless power transfer (WPT) technique. New developments in WPT technique motivate new avenues of research in different applications. Recently, WPT has been used in mobile phones, electric vehicles, medical implants, wireless sensor network, unmanned aerial vehicles, and so on. This review highlights up-to-date studies that are specific to near-field WPT, which include the classification, comparison, and potential applications of these techniques in the real world. In addition, limitations and challenges of these techniques are highlighted at the end of the article.

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“…The efficiency decreases exponentially with transmission distance. In order to improve the transmission efficiency, relay resonator has been proposed for power transfer [21], although such concept has been reported in waveguide and very low-power (milliwatts) wireless transmission [22]. With the use of the relay resonators, magnetically coupled resonators can be placed in closer proximity and therefore enjoy a higher energy efficiency for a given transmission distance, making such wireless power systems with more application potential for power level from several watts to a few kilowatts.…”

Section: Introductionmentioning

confidence: 99%

Wireless power domino-resonator systems with noncoaxial axes and circular structures

Zhong

Lee

Hui

2012

IEEE Trans. Power Electron.

153

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In this paper, a general analysis on wireless power domino-resonator systems with noncoaxial axes is presented. The mathematical formulation established can in principle be used to analyze wireless resonator systems with various domino forms. In this study, it is used to analyze and evaluate wireless dominoresonator systems with circular structures because such structures have more than one main power flow paths and have not been analyzed previously. Based on the superposition method, individual power flow paths are analyzed and then their interactions are emerged and explained with vector diagrams. Unlike the resonator pair used by Tesla, it is demonstrated that optimization of the domino systems can be achieved under "nonresonance frequency" operation and optimal load conditions. The shift of the optimal frequency from the resonance frequency is due to the multiple power flow paths. The theoretical results have been favorably verified with practical measurements obtained from two circular systems.Index Terms-Magnetic induction, wireless power transfer.

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The relay effect on wireless power transfer using witricity

Cited by 45 publications

References 2 publications

General Analysis on the Use of Tesla's Resonators in Domino Forms for Wireless Power Transfer

General Analysis on the Use of Tesla's Resonators in Domino Forms for Wireless Power Transfer

Opportunities and Challenges for Near-Field Wireless Power Transfer: A Review

Wireless power domino-resonator systems with noncoaxial axes and circular structures

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