Improved efficiency characteristics of wireless power charging system for superconducting MAGLEV train using inserted permanent magnets

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). This study aims for the design and analysis of antenna and receiver with high efficiency and stability in wireless power charging system for superconducting magnetic levitation (MAGLEV) train. Authors have already been developed superconducting wireless power charging (WPC) system for MAGLEV train using resonance copper antenna (Tx) coil HTS receiver (Rx) coil. Since the Tx and Rx coils can be placed on guidance and superconducting magnet at train, respectively, the installation cost of Tx can be considerably reduced. In this study, authors described and compared the practical design of permanent magnet between copper Tx and HTS Rx coils to improve the transfer efficiency through rectifying module since the permanent magnets can play a role to shift the transferred AC magnetic field. Authors measured rectifying currents under inserted permanent magnets with radio frequency (RF) power of 370 kHz below 150 W.