Mutual Inductance Calculation Of Circular Coils With Magnetic Shielding For Wireless Power Transfer System

Wireless Power Transfer(WPT)technology enables non-contact power transfer through electromagnetic coupling.Because of its secure,flexibile and convenient feature,it has attracted widespread attention and investigated by researchers.In engineering,the mutual inductance between the transmission coils and the receiving coils depends on parameters of coils structure.The misalignment between the transmission coil and the receiving coil may affect the mutual inductance,then the transfer efficiency may be decreased and the output power may be fluctuated,which leads to an unstable system.Thus,the analysis of the mutual inductance between coils is of great significance for the optimization of the coil structure and the improvement of the WPT system.In this paper,the following work is carried out for mutual inductance calculation of circular coils.The main research of this paper are summarized as follows:(1)Considering that there is no calculation method for circular coils with three layers of magnetic medium,a model of the circular coils with three layers of magnetic medium is given.Based on the method of magnetic potential vector analysis proposed in this paper,the mutual inductance calculation method for circular coils sandwiched with three layers of magnetic medium is proposed.(2)Considering that the influence of the misalignment between circular coils on the mutual inductance,the model of circular coils arbitrary positioned with magnetic medium is given,and the parameter vector method is proposed,which contributues to the mutual inductance calculation of circular coils arbitrary positioned with magnetic medium.(3)Considering that there is no calculation method for circular coils with magnetic disk,the model of circular coils with magnetic disk is given,and the modified truncated region eigenfunction expansion method is proposed to the mutual inductance calculation.The calculation method brings a theoretical foundation for exploring the influence of finite-size magnetic media on curcular coils.The mutual inductance data obtained by the formula mehod,finite element simulation and practical measurement are compared in each chapter of this paper,which proves the validity and accuracy of the proposed mutual inductance calculation formula.