Near Field Wireless Power Transfer for Multiple Receivers by Using a Novel Magnetic Core Structure

A Wireless Power Transfer (WPT) method is proposed by using a novel magnetic core structure. Similar to those transformers, magnetic cores are utilized as main object that conducts magnetic flux in the proposed cell. Power is transferred through near magnetic field and the distance between the receiver and the transmitter is thus relatively short. Every basic cell has only one primary side, where the magnetic cores of different permeabilities are combined to build a multi-transmitter structure for multiple receivers. By arranging and guiding the flux via a specific magnetic path, it offers some space of freedom for the locations of the multiple receivers. The usage of the magnetic core also increases the coupling coefficients between the primary-side transmitter and secondary-side receivers compared to core-less WPT using spiral coils. Analysis of the three working modes of the proposed WPT cell is presented. Experimental results show that the proposed basic cell with three receivers achieves 85% efficiency at 100W.