• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.149-155
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• 2014

In this paper, we study the complex mobile antenna for WPT(Wireless Power Transfer) with NFC(Near Field Communication) of inductive coupling using FPCB which has half thickness compared with the existing coil type antennas. Considering the pattern thickness of loop antenna, the analysis of electromagnetic wave absorber and battery's influence, absorber thickness, the ranges of design parameters are obtained. The proposed antenna has 0.45 mm thickness using single layer 3 oz FPCB and absorber. From measurement, the characteristics of NFC antenna can be satisfied with the specifications of EMVCo. and domestic mobile telecommunication and the transmission efficiency of the proposed WPT antenna is 68.1 % which is competitive with the existing coil type antenna. From the results of this paper, it has been confirmed that the proposed antenna can be used as the WPT and NFC antenna for mobile phone. Key words: Wireless Power Transfer, Near Field Communication, Mobile Phone Antenna, Absorber, FPCB.

• Progress in Superconductivity and Cryogenics
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• v.19 no.2
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• pp.29-32
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• 2017

The use of electronic devices such as mobile phones and tablet PCs has increased of late. However, the power which is supplied through wires has a limitation of the free use of devices and portability. Magnetic-resonance wireless power transfer (WPT) can achieve increased transfer distance and efficiency compared to the existing electromagnetic inductive coupling. A superconducting coil can be applied to increase the efficiency and distance of magnetic-resonance WPT. As superconducting coils have lower resistance than copper coils, they can increase the quality factor (Q-factor) and can overcome the limitations of magnetic-resonance WPT. In this study, copper coils were made from ordinary copper under the same condition as the superconducting coils for a comparison experiment. Superconducting coils use liquid nitrogen to keep the critical temperature. As there is a difference of medium between liquid nitrogen and air, liquid nitrogen was also used in the normal conductor coil to compare the experiment with under the same condition. It was confirmed that superconducting coils have a lower reflection-coefficient($S_{11}$) than the normal conductor coils.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.219-220
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• 2016

본 논문에서는 무선전력전송 시스템의 수신패드 측 전력변환회로 구성 방식에 따른 손실을 분석한다. 수신패드 측 전력변환회로를 DC-DC 컨버터로 구성한 구조와 bridgeless active rectifier (BAR)로 구성한 구조에 대해서 손실을 비교 분석한다. 수동소자에서의 손실은 수식적으로 계산하고, 전력용 반도체에서의 손실은 PSIM thermal module을 이용하여 분석한다.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.71-72
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• 2013

최근 철도시스템 분야에서도 기존의 접촉식 가공 전차선 급전 방식을 벗어나 새로운 개념의 에너지 전송시스템으로써 무선급전시스템의 다양한 응용 연구가 진행되고 있다. 본 논문에서는 전자기 유도방식의 일종인 무선급전시스템을 철도차량에 적용시키기 위해 운전조건에 따른 특성 연구를 수행 하였다. 전력 전송의 효율을 높이기 위해 유도급집전체(IPT, Inductive Power Transformer)의 누설 자속(Leakage Flux)을 보상할 수 있는 6-kW 60-kHz 시제품(Laboratory Prototype)을 제작하여 급전체와 집전체간 위치 변화에 따른 무선급전시스템의 전력전송량 변화를 알아보았다. 또한. 급전체와 집전체간 위치 변화에 따라 변하는 누설 자속을 측정하고 운전주파수를 변경하여 무선급전시스템의 전력전송량의 변화를 알아보았다.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.355-356
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• 2010

일반도로에서 자유주행이 가능한 온라인 전기자동차(On-Line Electric Vehicle, OLEV)에 적용하기 위해 전류원 급전방식의 직렬-직렬 공진형 자기유도 전력전달시스템(Inductive Power Transfer System, IPTS)을 개발하였다. OLEV용 IPTS에서는 급전선로의 누설 인덕턴스가 크고 집전픽업의 유무에 따라 입력측에 유기되는 전압변동이 심한 특성을 반영하여 급전측에 공진형 전류원을 사용한다. 또한 자화 인덕턴스와 집전픽업의 누설 인덕턴스를 포함하여 변압기를 완전 공진시킨다. 본 논문에서는 이러한 방식의 IPTS에서 최대출력을 전달하기 위한 조건을 찾고, 이로써 최대 출력전류 및 출력전력을 제한하는 요인을 찾아 최적설계를 할 수 있도록 하였다. 또한 실험을 통해 그 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.42-44
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• 2018

본 논문에서는 Bridgeless 정류기가 적용된 무선전력전송(Inductive Power System, IPT) 시스템의 성능 향상을 위한 스위칭 주파수의 변조 기법에 대해 제안한다. Bridgeless 정류기의 기존 제어 방식과 제안하는 제어 방식의 동작을 비교하고 3.3kW급 무선전력전송 시스템에 대한 시뮬레이션을 통해 제안하는 제어 방식에 대한 동작을 검증한다. 제안하는 제어 방식의 성능을 검증하기 위해 기존 제어 방식과의 손실을 비교 분석한다.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.158-159
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• 2019

본 논문은 전기자동차용 inductive power tranasfer (IPT) 방식의 양방향 무선전력전송에 활용 가능한 공진 네트워크를 선정한다. 각 공진 네트워크별 수식 분석을 통해 패드의 인덕턴스를 설계하고, 공진 네트워크 종류에 따라 달라지는 출력 특성을 분석한다. 분석 결과를 바탕으로 IPT 방식의 양방향 무선전력전송을 위한 공진 네트워크를 선정하고 시뮬레이션을 통하여 선정한 네트워크의 적합성을 검증한다.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.40-46
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• 2012

This paper presents contactless power supply systems using the Valtchev model in transportation systems. The major drawback of contactless systems is that the efficiency is lower than that of contact systems. The coupling coefficient of the contactless transformer is the most influential parameter on the system efficiency. Here, a new computer model for the contactless transfer system developed in the Korea Railroad Research Institute is presented. Also, simulations of the old model and the new model are compared with the prototype measurement to assure the model validity.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.6
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• pp.455-463
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• 2022

This study proposes a receiving pad identification coil for wireless charging of electric vehicles. The proposed coil identifies the shape of the receiving pad through magnetic coupling with the receiving pad. Therefore, the shape of the coil is designed to show the different magnetic properties of each receiving pad. The accuracy of this design is verified through finite element method simulation. Furthermore, the operation method of the secondary pad identification circuit is described, and the appropriate magnitude and length of the pulse voltage applied to this circuit for receiving pad identification are derived through simulation. The performance of the proposed identification coil set is verified by the experimental results.

• Journal of IKEEE
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• v.21 no.3
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• pp.195-201
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• 2017

High-power wireless transmission system becomes a key technology for the advance of battery-powered devices. The wireless power transfer devices are currently dominated by the inductive and capacitive wireless power transfer systems, which have relatively low power transmission capacity and low efficiency rather than the wired power transmission. The work presented in this paper proposes an alternative method of high-power transmission system, based on a variable speed motor system with a magnetic coupling. It enables high-capacity power transmission, high efficiency, and low possibility of failures, and the performance of the proposed scheme is verified by simulation and experiments.