Conceptual Design and Operating Characteristics of Multi-Resonance Antennas in the Wireless Power Charging System for Superconducting MAGLEV Train

Recently super high-speed magnetic levitation (MAGLEV) using high-temperature superconducting (HTS) magnet has been expected as next-generation transportation since superconducting magnet can keep mighty levitation force. The superconducting magnet at MAGLEV train should be continually charged with high power in order to keep stronger and stable levitation force. Practically, since conventional power supply unit should be attached to HTS magnet in the MAGLEV, a large thermal loss is indispensably caused by power transfer wires and joints, those have been one of essential obstacles in the superconducting MAGLEV train. As the wireless power transfer (WPT) technology based on strongly resonance-coupled method realizes large power charging without any wires through the air, there are advantages compared with the wired counterparts, such as convenient, safety, and fearless transmission of power. From this reason, the WPT systems have started to be applied to the wireless charging for various power applications, such as transportations (train, underwater ship, electric vehicle). However, it has obstacles to commercialize, such as delivery distance and efficiency. To solve the problems, authors proposed the technical fusion using HTS resonance coil in the WPT system since the superconducting wire has merits a larger current density and higher Q-value than normal conducting wire. In this study, authors described the conceptual design of HTS receiver (Rx) coil with multi-copper antenna (Tx) coils. The priority characteristics of moving HTS receivers under multi-copper Tx coils are compared with and various copper Rx coils with radio frequency power of 370 kHz below 300W.