An adaptive technique to improve wireless power transfer for consumer electronics

Hoang, H.; Lee, Seunggyu; Kim, Youngsu; Choi, Yun Ho; Bien, Franklin

doi:10.1109/tce.2012.6227430

Cited by 131 publications

(28 citation statements)

References 11 publications

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“…However, this technique is not suitable for implementation in standard systems, as it violates the ISM frequency band. Furthermore, a technique based on varying the k 12 by adjusting the d 12 and d 34 reported in [13,[18][19][20][21] improved efficiency, but the physical movement of the source and load coils is not feasible for implementation. Accounting for all of these factors, the proposed system proves to be more effective for improvising the efficiency in WPT systems.…”

Section: Simulation and Experimental Resultsmentioning

confidence: 99%

“…To obtain maximum efficiency for a WPT system, several methods have been proposed and studied in prior works [11][12][13][14][15][16][17][18][19][20][21]. These methods consist of adaptive circuits to optimize efficiency based on frequency control, impedance matching control, Q-factor tuning control and adjusting the coupling coefficient.…”

Section: Introductionmentioning

confidence: 99%

“…However, the range of tuning to obtain optimal efficiency was limited by the varactors employed in the circuit, and additionally, varactor losses reduced the total efficiency of the system. The work in [13,[18][19][20][21] details optimizing the efficiency based on varying the coupling between the coils. However, [13,[18][19][20] describes the method based on manually changing the distance between the coils to vary the coupling coefficient and obtain the optimal efficiency, whereas [21] suggests manually misaligning the source coil to vary the coupling coefficient to obtain maximum power transfer efficiency.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Simulation and Experimental Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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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“…The power transferred from the primary side and the power received by the secondary side can then be calculated by the product of the amplitudes of the voltage and current when the system operates at the resonant condition as Equations (9) and (10). Accordingly, the SS-WPT system efficiency is as shown in Equation (11).…”

Section: Ss-wpt System Circuit Modelmentioning

confidence: 99%

“…Due to the elimination of physical contacts between the source and the load and the energy can be transferred from a power source to isolated loads across a large air gap, through an alternating magnetic field, the WPT system can greatly enhance the flexibility and safety of electrical equipment. Therefore, this technology has been a very active research topic and has been widely used in implantable devices [2][3][4][5], electric vehicles [6][7][8][9], and portable devices [10,11] to power up a device or temporarily recharge its batteries.…”

Section: Introductionmentioning

confidence: 99%

A Design Method for Making an LCC Compensation Two-Coil Wireless Power Transfer System More Energy Efficient Than an SS Counterpart

et al. 2017

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Abstract:A new design approach is presented in this paper to show that under certain conditions, in a two-coil wireless power transfer system, the double-sided inductor-capacitor-capacitor (LCC) compensated wireless power transfer (LCC-WPT) system can be more energy efficient than the series-series (SS) compensated wireless power transfer (SS-WPT) system for the same load power, with special attention being paid to the effect that the parasitic coil and capacitor resistances have on the system efficiency. To make a fair comparison between the SS and LCC WPT systems, the direct current (DC) link voltage was adjusted to set equal load power for the two systems whilst using identical transmit and receive coils, coil-to-coil distance and load resistance. The system performance in terms of the system efficiency, the voltage stresses on the components, and the losses in the power devices were analysed for a practical system, comparing the LCC-WPT system and the SS-WPT system with respect to the load resistance. The effect of coil misalignment on the transferred power and efficiency for the two systems was compared. The theoretical proof and the conditions for meeting the objective are derived and practically verified in a two-coil WPT practical prototype, showing good agreement between analysis and experiments.

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Design and optimization of hybrid resonant loops for efficient wireless power transfer

Shi

Gao

Shen

et al. 2017

Circuit Theory & Apps

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Frequency splitting, caused by magnetic overcoupling, is a great challenge in resonant wireless power transfer, which leads to decrease of transfer efficiency. In this paper, to avoid the frequency splitting, a new design of hybrid resonant loops with an inner coil positioned in the transmitter is proposed for efficient power transfer. It is shown to suppress dramatic variation of mutual inductance when the distance between transmitter and receiver decreases.Analytical expressions of the mutual inductance and the transfer efficiency for the proposed resonant wireless power transfer system are calculated. To obtain a relatively uniform mutual inductance with respect to the distance, the proposed resonant loops are optimized. Simulation and experiments are also performed to validate the effectiveness of the proposed resonant loops in eliminating the frequency splitting. The transfer efficiency remains higher than 80% when the transfer distance decreases below a critical value where frequency splitting occurs for conventional resonant loops. Furthermore, lateral and angular misalignments between the resonant loops are also considered and investigated. The results indicate that the proposed resonant loops are also applicable in suppressing the frequency splitting even in case of misalignments.KEYWORDS frequency splitting, hybrid resonant loops, mutual inductance, transfer efficiency, wireless power transfer (WPT)

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An adaptive technique to improve wireless power transfer for consumer electronics

Cited by 131 publications

References 11 publications

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

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

A Design Method for Making an LCC Compensation Two-Coil Wireless Power Transfer System More Energy Efficient Than an SS Counterpart

Design and optimization of hybrid resonant loops for efficient wireless power transfer

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