Analysis of the Losses in Contactless Energy Transfer Systems Based on Different Distances Between Shielding, Ferrite and Coil

In this paper, the investigation of the losses caused by ferrites in contactless energy transmission systems is presented. The focus is to find the dependence of the distance between coil and ferrite on efficiency. Three different test setups are shown to prove this. First of all, there is a single-coil structure with ferrite and shielding. The quality factor $Q$ of the coil increases with distance. The second and third structures are systems with two coils but without shielding. In addition to the $Q$ factors, the product of the coupling factors $k$ and $Q$ are also examined here. In the last setup, the kQ product increases in addition to the $Q$ factor. The additional distance between the ferrites and the coil thus leads to a higher efficiency of the system.