The Transactions of The Korean Institute of Electrical Engineers (전기학회논문지)

The Korean Institute of Electrical Engineers (대한전기학회)
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Loss and Efficiency Dependence of a 6.78 MHz, 100 W, 30 cm Distance Wireless Power Transfer System on Cable Types

6.78 MHz, 100 W, 30 cm 거리 무선 전력 전송 시스템의 전선별 손실 및 효율 비교

  • Lee, Seung-Hwan (Metropolitan Transportation Research Center, Korea Railroad Research Institute) ;
  • Lee, Byung-Song (Metropolitan Transportation Research Center, Korea Railroad Research Institute) ;
  • Jung, Shin-Myung (Metropolitan Transportation Research Center, Korea Railroad Research Institute) ;
  • Park, Chan-Bae (Dept. of Railroad Operation System Engineering, Korea National University of Transportation)
  • Received : 2015.09.07
  • Accepted : 2015.10.08
  • Published : 2015.11.01
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Abstract

In MHz operating wireless power transfer systems, skin- and proximity-effect losses in the transmitter and the receiver coils dominate the coil-to-coil efficiency of the system. A Litz-wire was regarded as a common solution for minimizing such Ohmic losses in high frequencies. In this paper, equivalent series resistances of 12 different cables including Litz-wire and copper tubing have been calculated and measured for a 6.78 MHz, 100W, 30 cm wireless power transfer system. It has been shown that the copper tubing has lower resistances compared to the Litz-wire in that frequency and a wireless power transfer system with the copper tubing was able to achieve much higher efficiency than a system using the Litz-wire. Calculations of the resistances and efficiencies were accomplished with analytical equations and those calculations were evaluated by experimental results.

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References

  1. 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, no. 5834, pp. 83-6, Jul. 2007. https://doi.org/10.1126/science.1143254
  2. E. Waffenschmidt and T. Staring, "Limitation of inductive power transfer for consumer applications," in Power Electronics and Applications, 2009. EPE '09. 13th European Conference on, 2009, pp. 1-10.
  3. J. Acero, R. Alonso, J. M. Burdio, L. A. Barragan, and D. Puyal, "Frequency-dependent resistance in Litz-wire planar windings for domestic induction heating appliances," Power Electron. IEEE Trans. On, vol. 21, no. 4, pp. 856-866, 2006. https://doi.org/10.1109/TPEL.2006.876894
  4. New England Wire Technologies, "Litz design." [Online]. Available: http://www.litzwire.com/litz_design.htm. [Accessed: 22-Jul-2015].
  5. G. S. Smith, "Proximity Effect in Systems of Parallel Conductors," J. Appl. Phys., vol. 43, no. 5, pp. 2196-2203, 1972. https://doi.org/10.1063/1.1661474
  6. S.-H. Lee, "Design methodologies for low flux density, high efficiency, kW level wireless power transfer systems with large air gaps," PhD Dissertation, University of Wisconsin-Madison, 2013.