Maximizing DC-to-Load Efficiency for Inductive Power Transfer

Pinuela, Manuel; Yates, David C.; Lucyszyn, S.; Mitcheson, Paul D.

doi:10.1109/tpel.2012.2215887

Cited by 318 publications

(156 citation statements)

References 22 publications

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“…Therefore, the Q-factor of the loops reaches a finite maximum value, arising from the need to balance the these two factors. This relationship has also been reported for coils in [28] and has been subsequently utilised in the design of high-Q coils for state-of-the-art inductive WPT systems [29,30]. For the example case shown in Figure 9, the peak in the Q-factor occurs at 46 MHz.…”

Section: Coupling Coefficients and Q-factors Of Loops And Dipolessupporting

confidence: 71%

“…In order to fairly compare the figure of merit of the dipole system to that of the loop system, the parameter sweeps involving the dipoles were performed over the same frequency range Equation (28) and for the same separation distances Equation (30). The wire radius and conductivity of the dipole were similarly fixed at R a = 1 mm and σ = 6 × 10 7 S/m, respectively.…”

Section: Dipolesmentioning

confidence: 99%

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Investigation of High-Efficiency Wireless Power Transfer Criteria of Resonantly-Coupled Loops and Dipoles through Analysis of the Figure of Merit

2015

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The efficiency of a Wireless Power Transfer (WPT) system is greatly dependent on both the geometry and operating frequency of the transmitting and receiving structures. By using Coupled Mode Theory (CMT), the figure of merit is calculated for resonantly-coupled loop and dipole systems. An in-depth analysis of the figure of merit is performed with respect to the key geometric parameters of the loops and dipoles, along with the resonant frequency, in order to identify the key relationships leading to high-efficiency WPT. For systems consisting of two identical single-turn loops, it is shown that the choice of both the loop radius and resonant frequency are essential in achieving high-efficiency WPT. For the dipole geometries studied, it is shown that the choice of length is largely irrelevant and that as a result of their capacitive nature, low-MHz frequency dipoles are able to produce significantly higher figures of merit than those of the loops considered. The results of the figure of merit analysis are used to propose and subsequently compare two mid-range loop and dipole WPT systems of equal size and operating frequency, where it is shown that the dipole system is able to achieve higher efficiencies than the loop system of the distance range examined.

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Section: Coupling Coefficients and Q-factors Of Loops And Dipolessupporting

confidence: 71%

Section: Dipolesmentioning

confidence: 99%

Investigation of High-Efficiency Wireless Power Transfer Criteria of Resonantly-Coupled Loops and Dipoles through Analysis of the Figure of Merit

2015

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“…For energy harvesting applications, the work presented in [6] depicted long-range energy transfer based on inductive coupling for a distance of 6 m, but the power received was confined to 10.9 mW for a 246-W DC power input. Further, in [7], a designed and fabricated inductive power transfer system displayed higher efficiency of 77% at a distance of 30 cm. The work showed effective improvement in achieving power transfer efficiency for a longer range, but beyond 30 cm, the efficiency decreased gradually.…”

Section: Introductionmentioning

confidence: 96%

An Efficiency Enhancement Technique for a Wireless Power Transmission System Based on a Multiple Coil Switching Technique

Nair

Choi

2016

Energies

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For magnetic-coupled resonator wireless power transmission (WPT) systems, higher power transfer efficiency can be achieved over a greater range in comparison to inductive-coupled WPT systems. However, as the distance between the two near-field resonators varies, the coupling between them changes. The change in coupling would in turn vary the power transfer efficiency. Generally, to maintain high efficiency for varying distances, either frequency tuning or impedance matching are employed. Frequency tuning may not limit the tunable frequency within the Industrial Scientific Medical (ISM) band, and the impedance matching network involves bulky systems. Therefore, to maintain higher transfer efficiency over a wide range of distances, we propose a multiple coil switching wireless power transmission system. The proposed system includes several loop coils with different sizes. Based on the variation of the distance between the transmitter and receiver side, the power is switched to one of the loop coils for transmission and reception. The system enables adjustment of the coupling coefficient with selective switching of the coil loops at the source and load end and, thus, aids achieving high power transfer efficiency over a wide range of distances. The proposed technique is analyzed with an equivalent circuit model, and simulations are performed to evaluate the performance. The system is validated through experimental results that indicate for a fixed frequency (13.56 MHz) that the switched loop technique achieves high efficiency over a wider range of distances.

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“…However, a major limitation of such a two-coil system is that only one single device can be charged at any point in time. It also suffers from unpredictable inductive link performance since the power transfer efficiency is highly dependent on the actual coil alignment and the operating distance between the transmitter and receiver coil [1] [4]. In addition, a conventional two-coil WPT system provides a very limited set of design parameters (e.g.…”

Section: Introductionmentioning

confidence: 99%

Buck-Boost Single-Inductor Multiple-Output High-Frequency Inverters for Medium-Power Wireless Power Transfer

Lee

Jin

Tan

et al. 2019

IEEE Trans. Power Electron.

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 Abstract-In this paper, a non-isolated buck-boost singleinductor multiple-output (SIMO) DC-AC inverter for driving multiple independent high-frequency AC outputs of medium power, is proposed. Compared with traditional bridge-type inverters, the proposed buck-boost SIMO inverter achieves (i) a smaller component count, (ii) fully independent power control of its outputs, (iii) better scalability in increasing the number of AC output channels, and (iv) higher power efficiency. Operating in pseudocontinuous conduction mode (PCCM), the rated power of each output channel of this inverter can be high while attaining zero cross-regulation. The scalability factor of the proposed inverter is formally investigated and the theoretical maximum number of AC outputs is analytically derived. The targeted application of this SIMO-based inverter is for driving multiple transmitter coils to realize versatile multi-device medium-power wireless power transfer. A hardware prototype of a single-inductor threeoutput (SITO) buck-boost inverter delivering a medium power of 8.4 W per output channel has been constructed. It is experimentally verified that precise and independent current regulation of individual transmitter coil is achievable with the proposed inverter.

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Maximizing DC-to-Load Efficiency for Inductive Power Transfer

Cited by 318 publications

References 22 publications

Investigation of High-Efficiency Wireless Power Transfer Criteria of Resonantly-Coupled Loops and Dipoles through Analysis of the Figure of Merit

Investigation of High-Efficiency Wireless Power Transfer Criteria of Resonantly-Coupled Loops and Dipoles through Analysis of the Figure of Merit

An Efficiency Enhancement Technique for a Wireless Power Transmission System Based on a Multiple Coil Switching Technique

Buck-Boost Single-Inductor Multiple-Output High-Frequency Inverters for Medium-Power Wireless Power Transfer

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