Research on optimal distribution of the magnetic powder in wireless power transfer

Wireless power transfer system usually has the problems of low efficiency and small mutual inductance, and a scheme of variable mutual inductance coupling based on quantitative adjustable magnetic powder is described in this paper. Firstly, the relationship among mutual inductance, magnetic permeability and transmission efficiency between two coils is concluded according to the transformer principle and magnetic Ohm’s law; secondly, simulation analysis of the magnetic powder filled in the gap between the two coils is carried out to illustrate the best design. An experimental prototype is constructed to verify the effectiveness of the proposed WPT topology and the optimal magnetic circuit. The system efficiency is the highest with filling the magnetic powder uniformly in the transmitter’s center and the receiver’s edge, which is 16.4% higher than the traditional system. The theoretical calculation and simulation results are consistent with the previous optimization scheme, which provides a theoretical basis for the study of coil tuning and enhancing coil mutual inductance.