Operating Characteristics of Contactless Power Transfer From HTS Antenna to Copper Receiver With Inserted Resonator Through Large Air Gap

With the fast development of various wireless charging applications such as cell phones and electric vehicles, there is substantial interest in contactless power charging across an air gap. The contactless power transfer (CPT) system based on the resonance coupling method, which is composed of separate coils with the same resonance frequency, is feasible for exchanging energy within 2 m. However, generally, because the contactless charging system adopts a normal conducting wire, the size of the antenna is too large to be equipped to deliver a large amount of power promptly. From this point of view, we propose the combination of CPT technology with high-temperature superconducting (HTS) transmitter antenna, which we call the superconducting contactless power transfer (SUCPT). The superconducting transmitter antenna can deliver a mass amount of electric energy in spite of a small-scale antenna. The SUCPT technique is expected as a refined option to transfer a large amount of power and extend the distance. In this study, our research team achieved the improvement of transmission efficiency and extension of transfer distance using an HTS antenna in the inserted resonator coil between the HTS antenna and normal conducting receiver coils. We achieved improved transfer distance and quantity of about 25% compared with the normal conducting antenna under the same power conditions.