Mutual Inductance Analysis of Planar Coils with Misalignment for Wireless Power Transfer Systems in Electric Vehicle

This paper presents an analytical approach for calculating the magnetic field distribution excited by planar spiral circular coil and square coil for wireless power transfer (WPT) system. Based on Biot-Savart principle, the spatial magnetic flux density can be computed and the mutual inductance of the coils is calculated by numerical integrals with all possible variations of misalignments. The analytical calculation results are validated by finite element analysis. At last, comparison of the computed mutual inductance between the circular coil and the square coil is elaborated.