Design of flat magnetic core for inductively coupled coils in high efficiency wireless power transfer application

Abstract

A pad-like flat magnetic core with high permeability is adopted and was placed under the primary side coil as well as above the secondary side coil of wireless power transfer (WPT) system. It can be as a shielding for the magnetic field. Moreover, the insertion of the magnetic material increases the coupling coefficient of the two coils and thus reduces the leakage flux compared with core-less system. A WPT system with nominal power of 200W was built to validate the feasibility of the proposed method. Results show that after inserting the magnetic core, the power transfer efficiency is increased by about 30% with power transfer distance being 60mm–80mm.