• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.1
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• pp.16-22
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• 2002

The Proposed contactless charger employs a Pair of neighboring Printed circuit board (PCB) windings as a contactless energy transfer device, thereby making it amenable to low-Profile designs and suitable for applications to the portable telecommunication/computing electroncis in which stringent requirements for height, space, and reliability have to be met. The performance of the proposed charger is confirmed with experiments on a prototype charger developed for cellular phones

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.634-637
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• 2001

The proposed contactless charger employs a pair of neighboring printed circuit board windings as a contactless energy transfer device, thereby making it amenable to low-profile designs and suitable for applications to the portable telecommunication/computing electronics in which stringent requirements for height, space, and reliability have to be met. The performance of the proposed charger is confirmed with experiments on a prototype charger developed for cellular phones.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.678-681
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• 2000

Contactless battery charger with a "더" type core is proposed in this paper. The proposed take-apart transformer maintain a high coupling coefficient in spite of air gap. The ZV-ZCS method is used for the efficiency and stable opeation of the system.he system.

• Journal of Power Electronics
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• v.16 no.1
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• pp.102-110
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• 2016

Contactless power transfer technology is gaining increasing attention in city transportation applications because of its high mobility and flexibility in charging and its commensurate power level with conductive power transfer method. In this study, an inductively coupled contactless charging system for a 48 V light electric vehicle is proposed. Although this study does not focus on system efficiency, the generic problems in an inductively coupled contactless power transfer system without ferromagnetic structure are discussed. An active load matching method is also proposed to control the power transfer on the receiving side through a load matching converter. Small signal modeling and linear control technology are applied to the load matching converter for port voltage regulation, which effectively controls the power flow into the load. A prototype is built, and experiments are conducted to reveal the intrinsic characteristics of a series-series resonant inductive power charger in terms of frequency, air gap length, power flow control, coil misalignment, and efficiency issues.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.5
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• pp.407-417
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• 2003

Detachable transformers used in contactless battery chargers have poor power transfer characteristics because they have low coupling coefficients due to their gaps. The ㄷㅓ type core gives a high coupling coefficient in a contactless battery charger compared with standard cores such as EE, EC and UU. In this paper, characteristics of the ㄷㅓ type core is studied. Detailed analyses and comparisons are given based on the sinusoidal operation and square-wave operation. Reductions in output current, voltage and power are stated analytically and numerically. The analyses are verified by experiments conducted on a ZVS converter including a detachable transformer. The analyses and comparison method can be applied to other gaped transformer such as a PCB transformer.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.4
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• pp.265-271
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• 2000

A non-contact battery charger for cellular phone is designed using half-bridge series resonant converter. This converter utilizes series resonance to reduce the undesirable effect of large leakage inductance of the detachable transformer and ZVS operation can reduce switching loss and switching noise. In this paper, analysis and design procedure of half-bridge series resonant converter with detachable transformer is presented. The input voltage is 85VAC∼270VAC, and the output voltage and current is 4.1V and 800mA, respectively. Furthermore, a method of calculating the secondary current of the transformer to control the battery charging current in the constant current charging mode is proposed. The performance of the charger is verified through experiments.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.258-261
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• 2000

A non-contact battery charger which transfers energy using magnetic field has a difficulty with a feed-back control due to the interaction between the power and signal processing This paper proposes an effective method which uses auxiliary windings of transformer as signal path and copes with cross-talk using the MOSFET ringing phenomenon and ceramic filter. The power stage is half-bridge series resonant converter. Design procedure and experimental verification are presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.678-683
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• 2010

This paper presents a wireless (contactless) charging technique with a new core material called permalloy. For charging portable devices wirelessly, ferrosilicon or ferrite has been conventionally used. Due to high permeability of permalloy, charging efficiency can be significantly improved and subsequently this high efficiency increases charging distance between charger and portable devices. Comparative experimental studies demonstrate that the charging performance and efficiency with permalloy employed are significantly improved. The proposed wireless charging techniques can be used to charge portable devices efficiently.