• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.5
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• pp.38-43
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• 2009

We derive an equation that predicts the induced voltage across the receiving terminals of the three-coil head of a metal detector using a magnetic vector potential approach. We also derive an equation that relates the change of the impedance of the transmitting coil to the properties of the metal. We utilize the results to obtain the optimum spacing between the driving and the receiving coils at which the maximum induced voltage is attained. Further, we determine the position of the metallic object where the voltage reaches its peak. We verify our work by comparing the results with those of a previous work.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.614-619
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• 2017

In this paper, we optimize the wireless power transmission (WPT) coil, and then compare the EM simulation and measurement using magnetic coupling at 6.78 MHz. As transmission efficiency is affected by various factors such as the shape of the system, the size of the coils, the coil structure is proposed to consist of a helical resonant for transmission and a spiral resonant for reception. The size of the coil and the distance between the coils are determined to minimize the volume problem, and the shape of the coil are confirmed by EM simulation. A WPT system is designed with 860mm diameter top plate and cylindrical structure of column spaced 600mm apart, and the characteristics are simulated and measured. The simulation shows that ${\mid}S_{21}{\mid}$ is -0.53 dB with the efficiency of 88%, and the measurement result is that ${\mid}S_{21}{\mid}$ is -0.71 dB with the efficiency of 85%.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.202-203
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• 2013

본 논문에서는 무선 전력 전송 시스템의 두가지 회로방식(Topology)에 대해 분석하고 수신단 코일이 송신단 코일의 약 6.7%인 시스템을 설계한다. 또한 전원단 설계와 전원 저항, 부하 저항 설계방향을 제시한다.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.148-153
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• 2018

This paper proposes a single-input multiple-output (SIMO) self-resonant wireless power transmission system for transmitting power to multiple receivers and the characteristics are simulated and measured. A 600 mm diameter transmission single loop, a 600 mm diameter helical transmission resonant coil, an external diameter 900 mm planar spiral reception resonant coil, and an $80{\times}60mm^2$ flat plate square coil as a receiver are used to form a wireless power transmission system 600 mm away with the table structure. For optimal characteristics, the wireless power transmission coils are designed by EM simulation and equivalent circuit analysis, and the characteristics are simulated and measured. The variation of the efficiency with distance from the center of the spiral resonant coil is analyzed and the measured efficiency is 57% for one receiver and for the two receivers, the efficiency is 37% for each receiver.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.6
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• pp.1151-1158
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• 2011

Proximity magnetic sensor is able to detect the object target accurately in close range and it has been widely used in the underwater guided weapon system because there is no countermeasures from the target. In order to increase the damage of target by shock wave due to explosion of the underwater guided weapon system, the maximum detection range of the proximity magnetic sensor needs to be increased. In this paper, we describe the techniques of the optimum transmitting and receiving coils design using the Finite Element Method for the output power enhancement of the transmitter and the sensitivity improvement of the receiver. Finally, the proposed design techniques of the transmitter and the receiver were verified using a experimental setup and a prototype.

• Journal of Advanced Navigation Technology
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• v.26 no.3
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• pp.160-165
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• 2022

In this paper, we have proposed a magnetic resonant 6.78MHz WPT(wireless power transfer) technique which can be applied to a fixed transmitter and a receiver of varying relative distance and coil alignment, Power transmission characteristics are studied with the relative distance and misalignment ration of coil area between the transmitting and receiving coils. The coils are designed with the size of 60×80mm² by direct feeding method, and the characteristics are derived with the maximum relative distance of 50mm and horizontal area misalignment state of 0-40mm misalignment of coil center axis in the XY plane. The power transmission characteristics are compared between the 3D EM simulation and the measured data, and the power transmission shows larger than -3dB performance with the vertical distance of up to 30mm and 50% area misalignmment ratio. This work showsthe transmission characteristics according to relative distance and misalignment state between the cols and that direct feeding has advantage for the short relative distance and small misalignment ratio.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.35-43
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• 2014

In this paper, it is about to non-contact wireless power transmission according to various conditions of self induction principle between the two planar coils at a transmission unit and a receiving unit based on the theory of wireless power transmission. The experiments are occurred in order to power transfer of noncontact method from designed wireless circuits in the primely coil and secondary coil, and the applying to Half Bridge Resonant converter transmission unit and receiving unit. and that were able to prepared circumstance to calculate of the output voltage and power source. The main power of the inductive coupling the resonant converter at the transmission unit is converted electrical energy using the solar cell module and artificial light source (halogen lamp) as a replace light and received 24 V power supply from solar power was used a input power source for the wireless power transmission device. Experimental results, to received of power is used to illuminate the lighting and to charge the battery in receiving circuit.And the wireless power transmission efficiency measured at the output side of the transmission unit is obtained about 70% to 89% compared to input power of receiving unit.In addition, efficiency were tested through ID verification method and comparing the phase difference between the voltage when foreign substances interfere with wireless power transmission.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1549-1550
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• 2015

본 논문에서는 초전도 공진 코일의 차폐 소재 위치에 따른 무선전력전송 특성을 분석하였다. 차폐 소재는 송신 코일로부터 3cm, 8cm, 18cm, 28cm 간격을 두었다. 차폐 소재로는 알루미늄과 플라스틱을 적용하였다. 그 다음 Network Analyzer를 이용하여 S-parameter($S_{11}$)를 분석하였다. 그 결과, 알루미늄 차폐 소재를 5cm 간격을 두어 적용하였을 때 반사계수가 가장 높았다. 하지만 플라스틱 차폐소재에서는 어떤 위치에서도 비슷한 반사계수를 나타냄을 확인하였다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.200-201
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• 2017

무선전력전송 시스템의 전력 수신부는 많은 경우 송신부에 비해 크기가 작으므로 자계결합 에너지링크 코일의 권선을 비대칭으로 설계할 필요가 있다. 본 논문은 직렬 공진 보상 구조의 자계결합 무선전력전송에서 에너지링크 전압이득과 전력전송효율을 동시에 고려해 전력변환회로 관점에서의 비대칭 코일의 도식적인 분석 및 설계 방법을 제안한다. 제안하는 설계평면을 통해 에너지링크 코일의 정렬이 어긋날 때 혹은 부하요구가 변할 때 에너지링크의 전압이득과 전력전송효율 변화를 직관적으로 예측할 수 있으며 주어진 설계조건에 따라 에너지 링크를 간단히 설계할 수 있다. 본 제안방법은 회로 시뮬레이션을 통해 검증 되었다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.7-8
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• 2014

본 논문은 다이폴 코일 공진방식(DCRS, Dipole Coil Resonant System)을 사용한 원격 무선전력전송 개발 사례를 소개한다. 제안된 다이폴 코일 공진방식은 기존의 자기결합 공진방식(CMRS, Coupled Magnetic Resonance System)에 비하여 송신, 수신코일로만 이루어진 간단한 코일 구조와 작은 부피를 가지며, 공진도 Q를 100이하로 설계하여 주변 환경 변화에 강인한 전력전달 특성을 가진다. 본 논문에서는 원전 중대사고 시 격납건물 필수계측기용 소형 비상전원으로 개발된 10W급 7m 원격 무선전력전송 장치의 구성 및 설계과정을 제시한다.