Effects and Properties of Contactless Power Transfer for HTS Receivers With Four-Separate Resonance Coils

Contactless power transfer (CPT) technology is an available option to realize the possibility of power delivery and storage with connector-free devices across an air gap. The CPT system based on a strong resonance coupling, which consists of four separate coils with the same resonance frequency, can possibly exchange energy within 2 m. We propose a combination CPT technology with HTS receiver coils, and call it the superconducting contactless power transfer (SUCPT) system. The SUCPT technique is expected to be a noble option for transferring electric power from room temperature to a very low temperature vessel without connectors and can improve the portability of the superconducting system. The SUCPT resonance coils consist of source (copper), Tx (copper), Rx (HTS), and load (HTS) coils. The impedance matching for electromagnetically coupled resonators between Tx and Rx coils is sensitive and plays an important role to improve transfer efficiency and distance. In this study, we examined the transmission efficiency and properties of the SUCPT phenomenon with four separate coils from antenna parts of copper coils at 300 K to receiver parts of HTS wire at 77 K as long as the receiver is within 1.1 m distance. Also, we obtained adequate relations between directionality and transmission efficiency for different positions.