Adaptation of Discrete-Type Cores for Secondary Coils of Wireless Power Transfer System for Railway

Abstract

This paper examines the shapes of cores for secondary coils of the wireless power transfer (WPT) system for a railway. An infinitely long cable-type coil is utilized as the primary coil for the WPT system because it is economical. Thus, this paper examines the ferrite core shapes for the secondary coils that are suitable for an infinitely long primary coil. The cores should be as thin as possible to reduce weight. However, bonding small cores to manufacture larger thin cores reduces the performance of the secondary coils. As a result, the cores are paradoxically required to be thicker. Therefore, this paper proposes the adaptation of thicker discrete-type cores with the same volume as conventional flat-type cores for the secondary coils.