Circuit Analysis and Characterization of Contactless Power Transfer System with Variable Impedance

A contactless power transfer system using a repeater coil (Repeater Coil topology) has been proposed as a method of suppressing overcurrent without power control during misalignment or no-load. By installing a repeater coil between the primary and secondary coils, it is possible to increase the input impedance in the case of misalignment of the secondary coil or no-load condition. In addition, another a contactless power transfer system using primary parallel and secondary series resonance capacitors (PS Capacitor topology) has been proposed. In the PS Capacitor topology, the input impedance can be increased during misalignment of the secondary coil or no-load condition similar to the Repeater Coil topology. In this paper, we evaluated the characteristics of both these topologies. First, we conducted a circuit analysis of the Repeater Coil topology and proposed a design method. In addition, we theoretically clarified the characteristic difference of the two topologies and experimentally evaluated the characteristics.