A novel metal detector using the quality factor of the secondary coil for wireless power transfer systems

Fukuda, Shin–ichi; Nakano, Hiroki; Murayama, Y.; Murakami, Tomomichi; Kozakai, Osamu; Fujimaki, Kenichi

doi:10.1109/imws.2012.6215802

Cited by 63 publications

(25 citation statements)

References 3 publications

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“…Unfortunately, as WPT systems transfer high power, the losses generated are small and difficult to detect [172]. Another approach is to use the quality factor Q of the secondary pad [174]. This method is viable for stationary systems that include alignment mechanisms.…”

Section: Foreign Object Detection and Ev Detection 22mentioning

confidence: 99%

A critical review on wireless charging for electric vehicles

Machura

2019

Renewable and Sustainable Energy Reviews

220

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Electric vehicles (EVs) have recently been significantly developed in terms of both performance and 10 drive range. There already are various models commercially available, and the number of EVs on road 11 increases rapidly. Although most existing EVs are charged by electric cables, companies like Tesla, 12 BMW and Nissan have started to develop wireless charged EVs that don't require bulky cables. 13 Rather than physical cable connection, the wireless (inductive) link effectively avoids sparking over 14 plugging/unplugging. Furthermore, wireless charging opens new possibilities for dynamic chargingcharging while driving. Once realised, EVs will no longer be limited by their electric drive range and the requirement for battery capacity will be greatly reduced. This has been prioritised and promoted worldwide, particularly in UK, Germany and Korea. This paper presents a thorough literature review on the wireless charging technology for EVs. The key technical components of wireless charging are summarised and compared, such as compensation topologies, coil design and communication. To enhance the charging power, an innovative approach towards the use of superconducting material in coil designs is investigated and their potential impact on wireless charging is discussed. In addition, health and safety concerns about wireless charging are addressed, as well as their relevant standards. Economically, the costs of a wide range of wireless charging systems has also been summarised and compared.

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Section: Foreign Object Detection and Ev Detection 22mentioning

confidence: 99%

A critical review on wireless charging for electric vehicles

Machura

2019

Renewable and Sustainable Energy Reviews

220

View full text Add to dashboard Cite

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“…(e) Detection method based on a Q factor deterioration From Equations (4), (5) and 6, the quality factor varies with changes in the input impedance and resonance frequency, which can be used to reveal the appearance of metal objects. In [79], a Q factor deterioration detection method was proposed, where the Q factor of the receiving coil was measured to validate nearby metal objects. The equivalent circuit is shown in Figure 8.…”

Section: (D) Detection Methods Based On a Resonance Frequency Deviationmentioning

confidence: 99%

“…Therefore, the resonance frequency tends to increase while the Q factor decreases, and the Q factor can be used as a detection parameter. In [79], the Q factor of the receiving coil was monitored by measuring the voltage on both sides of the resonance capacitance. The receiver acts as an LC high-pass filter, and the Q factor can be expressed as the peak level of (…”

Section: (D) Detection Methods Based On a Resonance Frequency Deviationmentioning

confidence: 99%

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Foreign Object Detection for Electric Vehicle Wireless Charging

Xia

Yuan

et al. 2020

Electronics

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Wireless power transfer technology is being widely used in electric vehicle wireless-charging applications, and foreign object detection (FOD) is an important module that is needed to satisfy the transmission and safety requirements. FOD mostly includes two key parts: metal object detection (MOD) and living object detection (LOD), which should be implemented during the charging process. In this paper, equivalent circuit models of a metal object and a living object are proposed, and the FOD methods are reviewed and analyzed within a unified framework based on the proposed FOD models. A comparison of these detection methods and future challenges is also discussed. Based on these analyses, detection methods that employ an additional circuit for detection are recommended for FOD in electric vehicle wireless-charging applications.

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“…With the continuous development of wireless power transfer (WPT) technology and its commercialization process, its security issues attract more and more attention [1][2][3][4]. One such issue is that a foreign metal object will deteriorate the WPT system performance [5,6], and the eddy current of the metal object will cause heating problems, possibly causing a fire hazard [7].…”

Section: Introductionmentioning

confidence: 99%

Effects of Foreign Metal Object on Soft-Switching Conditions of Class-E Inverter in WPT

et al. 2018

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A foreign metal object will deteriorate the performance of wireless power transfer (WPT) systems and cause insecurity issues. Therefore, the influence principles and rules of foreign metal objects on soft-switching conditions of Class-E inverters and the performance of WPT systems are developed in this paper. The effects of different metal materials on coil parameters at different frequencies and positions are analyzed first, then the effects of foreign metal objects on soft-switching conditions of Class-E inverters and the power transfer capability of WPT systems are investigated. Principle analyses and simulation results demonstrate that there are significantly different effects on the soft-switching conditions and power transfer when a foreign metal object is placed near the transmitter coil or the receiver coil. In addition, the monotonicity of the variation in power transfer also depends on the position of the foreign metal object. Finally, a WPT experimental prototype with a Class-E inverter is implemented to verify the influence principles and rules of foreign metal objects. The experimental results are highly consistent with the principle analyses and simulation results.

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A novel metal detector using the quality factor of the secondary coil for wireless power transfer systems

Cited by 63 publications

References 3 publications

A critical review on wireless charging for electric vehicles

A critical review on wireless charging for electric vehicles

Foreign Object Detection for Electric Vehicle Wireless Charging

Effects of Foreign Metal Object on Soft-Switching Conditions of Class-E Inverter in WPT

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