Asymmetry in Wireless Power Transfer Between a Superconducting Coil and a Copper Coil

Wireless power transfer (WPT) is of increasing interests today. High temperature superconducting (HTS) WPT has been demonstrated to be more efficient than copper WPT. In our previous work, we found that the efficiency of WPT from a copper coil to a HTS coil is lower than the efficiency of WPT from the same HTS coil to the same copper coil. Thus, the transmitter and the receiver are asymmetric and this asymmetry degrades WPT performance. In this paper, it is demonstrated theoretically and experimentally that for WPT between a HTS coil and a copper coil: asymmetry does exist and influences properties; the root of the asymmetry is the different resistances between the HTS coil and the copper coil; the effects of the asymmetry can be eliminated by optimizing the load; the proposed theoretical calculation fits the experimental results well.