High-Temperature Superconducting Capacitor and Its Application to a Superconducting Wireless Power Transfer System

A capacitor made of high-temperature superconducting (HTS) electrode plates and a dielectric layer, or “HTS capacitor” for short, has the potential advantages of working with other HTS devices at 77 K and producing low conductive loss at high frequency. It may have a specific application to cryogenic systems at high frequency, such as superconducting wireless power transfer (SWPT) systems. Working with HTS resonant coil in an adiabatic container, the HTS capacitor can also reduce the heat leakage of the cooling system. Considering a lack of relevant experimental study at present, an HTS capacitor composed of YBCO (YBa
₂
Cu
₃
O
_7-x
) tapes and a polyimide layer is proposed in this paper and tested in an SWPT system. Its characteristics and influences on the SWPT system are presented in detail by theoretic analysis and experimental investigation. A comparative experiment is carried out between the fabricated HTS capacitor and other capacitors made from normal materials. Finally, it is confirmed experimentally that the HTS capacitor can have a high-quality factor, work with the HTS resonant coil normally at 77 K, and provide the SWPT system with a performance enhancement.