A novel method for calculating the mutual inductance between two perpendicular coils in wireless power transfer

SummaryThe perpendicular coil is increasingly applied in some wireless power transfer (WPT) systems where space position is limited. The existing method of calculating the mutual inductance between perpendicular coils is mainly applied to rectangular and circular coils. However, the practical rectangular coil often has rounded corners, so it unavoidably introduces systematic errors. Concerning this issue, this paper proposed an analytical method to calculate the mutual inductance between mutually perpendicular round‐corner rectangular (RCR) coils. The proposed method is based on a second‐order vector potential (SOVP) model where the mutual inductance between the coils is described as a double integral formula. In this formula, a novel shape and position function is introduced. This shape and position function describes not only RCR coils but also rectangular (including square), circular, and runway ones. A series of experiments were used to validate the proposed method. According to the consistency validation, the proposed method can be more generalized for calculating the mutual inductance of rectangular and circular coils. Through experimental comparison, the proposed method computes the mutual inductance between the perpendicular coil in excellent agreement with the measured ones. Therefore, the proposed method unifies the mutual inductance calculation of mutually perpendicular circular, rectangular (square), runway, and RCR coils and can provide an important basis for designing WPT systems using the above coils.