Effects and Design Considerations of Inserted Resonator to Improve Efficiency Including Rectifying Circuit for Superconducting Wireless Power Transfer System for Electric Vehicle

The wireless power transfer (WPT) technology based on strongly resonance coupled method realizes large power charging without any wires through the air. Recently, the WPT systems have started to be applied to the wireless charging for electrical vehicles (EVs) because of their advantages compared with the wired counterparts, such as convenient, safety and fearless transmission of power. However, it has obstacles to commercialize such as delivery distance and efficiency. To solve the problems, we proposed the technical fusion using HTS antenna in the WPT system, it is called as, superconducting wireless power transfer for electric vehicle (SUWPT4EV) system. Since the superconducting wire has merits a larger current density and higher Q value than normal conducting wire, the HTS antenna enables to deliver a mass amount of electric energy in spite of a small scale antenna. Thus, SUWPT4EV system has been expected as a reasonable option to improve the transfer efficiency of large electric power. Authors already demonstrated the efficienct effects for inserted resonator using simply copper tube wires, which structure is helix type of multi layers. In this study, as a practical approach, authors evaluated the SUWPT4EV system with inserted copper type resonator, which structure is a rectangular shape of single layer to reduce installation volume. Based on the evaluation results, authors deduced the practically alternative structure for the inserted resonator to reduce the installation space as well as to improve transmission power, compared with non-resonator SUWPT4EV system under radio frequency (RF) power of 370 kHz below 500 W.