• 한국정보통신학회논문지
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• 제18권8호
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• pp.1798-1804
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• 2014

자기 공진 결합 (resonant inductive coupling) 현상을 이용한 무선 전력 전송 기술을 구현하기 위하여 새로운 구조의 자기 공진기를 제시한다. MIT 연구팀이 제안한 헬릭스 (helix) 모양의 자기 공진기의 크기를 줄이고, 공진 주파수 10 MHz를 유지하며, 무선 전력 전송 효율이 크게 열화 되지 않도록 설계한다. 새로운 구조의 자기 공진기는 스파이럴 (spiral) 모양으로써 헬릭스 모양 대비 소형화를 달성하였다. 스파이럴 모양 ($1,696cm^3$)의 자기 공진기는 헬릭스 모양 ($59,376cm^3$) 대비 97% 소형화를 이룩하였고, 무선 전력 전송 효율은 기존 기술 (2 m 거리에서 40 % 전송 효율) 대비 9% 이하로 차이를 줄임으로써 무선 전력 전송 기술의 실용화에 기여할 수 있게 되었다.

• 전기전자학회논문지
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• 제23권1호
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• pp.306-309
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• 2019

Wireless charging is a technology of transmitting power through an air gap to an electrical load for the purpose of energy dissemination. Compared to traditional charging with code, wireless power charging has many benefits of avoiding the hassle from connecting cables, rendering the design and fabrication of much smaller devices without the attachment of batteries, providing flexibility for devices, and enhancing energy efficiency, etc. A transmitting coil and a receiving coil for inductive coupling or magnetic resonant coupling methods are available for the near field techniques, but are not for the far field one. In this paper, the wireless power transfer (WPT) circuit by using magnetic resonant coupling method with a resonant frequency of 13.45 Mhz for the low power system is implemented to measure the power transmission efficiency in terms of mutual distance and omnidirectional angles of receiver.

• 전기학회논문지
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• 제62권3호
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• pp.349-354
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• 2013

Wireless power transmission introduced by Tesla has instrumented by many scientists of the world. This technique first was utilized as wireless communications such as radio in long range transmission. And contactless transmission using inductive property was used on white goods. In 2007, MIT' lab introduced that new wireless power transmission by magnetic resonance which has about 50% efficiency and 2M transmission distances, it was a chance to refocus a new possibility of wireless power transmission. In this paper, using LC coupling compensate the short distances of contactless transmission, this simple method could transmit about 30cm distances. Using this approach, it can be solved the short transmission distances, a drawback of Electromagnetic inductive coupling method.

• 전기전자학회논문지
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• 제23권2호
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• pp.747-750
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• 2019

웨어러블 디바이스는 일상생활에서 실질적으로 필수적이며 사용자들에게 편리하게 이용되고 건강관리와 의학 분야 등에 활용되고 있다. 전력분야에서 전원 배터리의 사용시간의 한계를 극복하고 효율적인 충전방법에 관한 많은 연구가 진행되고 있다. 무선전력전송은 전선을 사용하지 않고 무선으로 전기장을 부하에 전력을 전달하는 기술이다. 이 전송기술은 저 전력의 스마트폰에서부터 고 전력을 사용하는 철도 충전시스템까지 응용분야가 다양하다. 충전방식은 유도방법과 자기공진방법의 2 종류로 나누는데 자기공진주파수는 13.45 Mhz를 사용하였다. 본 연구에서는 전송효율을 측정 비교하기 위하여 2 종류의 하드웨어를 구현한 후 비교하는데 있다.

• Journal of electromagnetic engineering and science
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• 제15권3호
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• pp.194-198
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• 2015

Magnetic resonant coupling is more efficient than inductive coupling for transferring power wirelessly over a distance. However, a conventional resonant wireless power transfer (WPT) system requires a transmitter and receiver pair in exactly coaxial positions. We propose a resonator that can serve as an omnidirectional WPT system. A magnetic field will be generated by the current flowed through the transmitter. This magnetic field radiates omnidirectionally in the x-y plane because of the crisscross structure characteristic of the transmitter. The proposed resonator is demonstrated by using a single port. To check the received S21 and transfer efficiency, we moved the receiver around the transmitter at different distances (50-350 mm). As a result, the transmission efficiency is found to be 48%-54% at 200 mm.

• 전기전자학회논문지
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• 제22권3호
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• pp.846-849
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• 2018

Wireless power transfer (WPT) is the technology that enables the power to transmit electromagnetic field to an electrical load without the use of wires. There are two kinds of magnetic resonant coupling and inductive coupling ways transmitting from the source to the output load. Compared with microwave method for energy transfer over a long distance, the magnetic resonance method has the advantages of reducing the barrier of electromagnetic wave and enhancing the efficiency of power transmission. In this paper, the wireless power transfer circuit having a resonant frequency of 13.45 MHz for the low power system is studied, and the hardware implementation is accomplished to measure the power transmission efficiency for the distance between the transmitter and the receiver.

• 한국정보전자통신기술학회논문지
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• 제9권6호
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• pp.578-583
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• 2016

본 논문에서는 이중루프 구조를 갖는 다중모드 무선전력전송 시스템을 제안하였다. 본 논문에서 제안한 다중모드 무선전력전송 시스템은 두 개의 서로 다른 주파수 6.78 MHz 자기공진 무선전력전송 모드와 13.56 MHz NFC 모드로 동작하는 외부 루프 모듈과 두 개의 서로 다른 주파수에서 동작하는 자기유도 표준인 WPC 모드와 PMA 모드로 동작하는 외부 루프와 연결된 내부 루프 모듈로 구성된다. 실제 상용 스마트폰 배터리 커버에 장착하기 위해 페라이트 시트를 포함한 $45{\times}90{\times}0.35mm3$ 크기에 맞춰 설계 및 최적화 되었다. 제안된 다중모드 무선전력전송 시스템은 기존의 자기유도방식 표준에 해당하는 WPC와 PMA를 지원할 뿐만 아니라 6.78 MHz 및 13.56 MHz에서 20 dB 이상의 반사손실 특성을 나타내었고 6.78 MHz 자기공진 무선충전 환경에서는 공진코일 간 70% 이상의 효율 특성을 갖는다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.215-217
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• 2004

This paper shows the analysis of the inductive power transfer system in conjunction with series resonant converter operating variable high frequency. Of particular interest is the sensitivity of the complete system to variations in operational frequency and parameters. In inductive power transfer system, electrical power is transferred from a primary winding in the form of a coil or track, to one or more isolated pick-up coils that may relative to the primary. The ability to transmit power without contact enables high reliability and easy maintenance that allows inductive power transfer system to be implemented in hostile environments. This technology has found application in many fields such as electric vehicles, PRT(Personal Rapid Transit) etc. The coupling between the primary and secondary is then presented to include the effects of parameter and operational frequency variation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 추계학술대회 논문집
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• pp.25-26
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• 2012

Wireless power transmission introduced by Tesla has instrumented by many scientists of the world. This technique first was utilized as wireless communications such as radio in long range transmission. And contactless transmission using inductive property was used on white goods. In 2007, MIT' lab introduced that new wireless power transmission by magnetic resonance which has about 50% efficiency and 2M transmission distances, it was a chance to refocus a new possibility of wireless power transmission. In this paper, using LC coupling compensate the short distances of contactless transmission, this simple method could transmit about 30cm distances. Using this approach, it can be solved the short transmission distances, a drawback of Electromagnetic inductive coupling method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1413-1418
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• 2004

This paper shows the analysis of the inductive power transfer system in conjunction with series resonant converter operating variable high frequency. Of particular interest is the sensitivity of the complete system to variations in operational frequency and parameters. In inductive power transfer system, electrical power is transferred from a primary winding in the form of a coil or track, to one or more isolated pick-up coils that may relative to the primary. The ability to transmit power without contact enables high reliability and easy maintenance that allows inductive power transfer system to be implemented in hostile environments. This technology has found application in many fields such as electric vehicles, PRT(Personal Rapid Transit) etc. The coupling between the primary and secondary is then presented to include the effects of parameter and operational frequency variation.