Inductive contactless power transfer system with coaxial coreless transformer for dc power distribution

This paper proposes to use contactless power transfer (CPT) systems as electric plugs and outlets for household dc distribution system. In dc systems, there are higher risk of electric shock and longer arc discharge at disconnection compared with ac systems. The proposed system can connect and disconnect safely without electric shock and arc discharge because there is no contactor between primary side and secondary side. In this paper, an inductive contactless power transfer system was adopted. To reduce cost of system, a coreless transformer was selected. CPT circuit topologies and design of transformer coil form were considered. As suitable structure, a coaxial cylindrical transformer was proposed. Simulation results of 1 kW 400 kHz model and experimental results of developed 1 kW 400 kHz and 600 kHz prototypes were presented. The proposed system showed maximum efficiency over 93%.