Design of contactless inductive energy transmission systems with large air-gap

A contactless inductive energy transmission system (CIETS) transmits electric energy via a alternating magnetic field through an air-gap. In contrast to a non air-gap energy transmission system, the power capacities per frequency of the primary and secondary sides in a CIETS are different. Therefore, a new method is needed for designing a CIETS that has an asymmetric structure. In this paper, we propose a new design method to improve the efficiency of CIETSs by increasing the coupling coefficient. Core shape is an important parameter to be optimized in order to increase the coupling coefficient. Several core shapes are analyzed by a finite element method (FEM). Calculated coupling coefficients are compared to determine the optimal core shape design.