The Journal of Korean Institute of Information Technology (한국정보기술학회논문지)

Korean Institute of Information Technology (한국정보기술학회)
권호 표지
DOI QR코드

DOI QR Code

Design and Analysis of High Q-factor LC Resonant Coil for Wireless Power Transfer

무선전력전송을 위한 High Q-factor LC 공진코일 설계 및 해석

  • Yoo, Eun-Kyoung (Dept. of Electrical Engineering, Chonbuk National University) ;
  • Ko, Young-Ho (Dept. of Electrical Engineering, Chonbuk National University)
  • 유은경 (전북대학교 전기공학과) ;
  • 고영호 (전북대학교 전기공학과, 스마트그리드연구센터)
  • Received : 2013.11.25
  • Accepted : 2013.12.12
  • Published : 2014.01.31
⟨ Previous Next ⟩

Abstract

This paper studied on design and analysis of LC resonant coil for WPT based on magnetic resonance method. Transmitting resonant coil is presented $120mm{\times}100mm$ in order to high power transfer and receiving resonant coil is a model at the A4WP. The proposed design was compared with simulation and experiment to optimal design. To reduce resistance by proximity effect, the ratio of conductor diameter and pitch between conductors(p/a) obtained proper size. Using optimal design, a 6.78MHz wireless charging system for a mobile device is designed and fabricated. It is analyzed a transfer efficiency and magnetic field about the distance between designed transmitting and receiving coil. When placed at a distance of 20mm, measurement result shows that the power transfer efficiency is 80.4% in coaxial and each 30% in case of two receiving coils placed in asymmetric over the transmitting coil.

본 논문에서는 자기 공진형 무선전력전송에 대한 LC 공진 코일의 설계 및 특성을 제시하였다. 송신 공진코일은 높은 전력을 보내기 위해 $120mm{\times}100mm$ 크기로 하고, 수신 공진코일은 A4WP의 권장 크기인 $44.01mm{\times}61.01mm$크기로 구성했으며, 시뮬레이션과 실험을 통하여 최적화 설계를 수행하였다. 코일의 자기 인덕턴스와 저항을 구하여, 고주파에서 나타나는 근접 효과(proximity effect)에 의한 저항 이론을 적용하였다. 근접 효과에 의한 저항을 줄이기 위해 적절한 도선의 직경과 도선 사이의 간격에 대한 비(p/a)를 구하여 최적화 설계하였다. 가장 높은 Q-factor를 가졌을 경우의 p/a를 적용하여 6.78MHz에서 전송특성을 알아보았다. 송 수신 공진코일이 20mm 거리에 동축으로 놓여 있을 때는 80.4%, 두 개의 수신 공진코일이 동일 거리에 비대칭으로 놓여 있을 때는 각각 29.5%의 전송효율을 얻었다.

Keywords

References

  1. W. C. Brown, "The History of Power Transmission by Radio Waves", IEEE Trans. micro. theory tech., Vol. MTT-32, No. 9, pp. 1230-1242, Sep. 1984.
  2. A. Kurs, A. Karalis, R. Moffatt, J. D. Joannopoulos, P. Fisher, and M. Soljacic, "Wireless power transfer via strongly coupled magnetic resonances", Science, Vol. 317, pp. 83-86, Aug. 2007. https://doi.org/10.1126/science.1143254
  3. Hyeon-Chang Son, Jin-Wook Kim, Do-Hyeon Kim, Kwan-Ho Kim, and Young-Jin Park, "Self-Resonant Coil with a Coaxial-like Capacitor for Wireless Power Transfer", KIEE, pp. 5-6, July 2011.
  4. Yong-Seok Lim, Woo-Jin Yang, and Seung-Ok Lim, "Wireless power transfer technology implementation for mobile devices based on magnetic resonances", KEIT, Vol. 29, No. 11, pp. 75-80, Oct. 2012.
  5. S. H. Lee and R. D. Lorenz, "Development and validation of model for 95% efficiency 220-W wireless power transfer over a 30-cm airgap", IEEE Transactions on Industry Applications, Vol. 47, No. 6, pp. 2495-2504, Nov. 2011. https://doi.org/10.1109/TIA.2011.2168555
  6. William B. Kuhm, "Analysis of current crowding effects in multi turn spiral inductors", IEEE TRANS MTT, Vol. 49, No. 1, pp. 31-38, Jan. 2001.
  7. Je-Young Park, "Study on the Characteristic of MEMS Inductor with various Substrate", Inha University, Nov. 2007.
  8. Ryan Tseng, Bill von Novak, Sumukh Shevde, and Kamil A. Grajski, "Introduction to the Alliance for Wireless Power Loosely-Coupled Wireless Power Transfer System Specification Version 1.0", IEEE Wireless Power Transfer Conference 2013, Technologies, Systems and Applications, pp. 79-84, May 2013.

Cited by

  1. Investigation of AC losses in horizontally parallel HTS tapes vol.30, pp.7, 2014, https://doi.org/10.1088/1361-6668/aa6fc2