A Multi-Domain Model for Variable Gap Iron-Cored Wireless Power Transmission System

Abstract

Wireless power transfer (WPT) devices represent one of the most efficient and increasingly used technologies for the transfer of data and power in the near-field range. This work analyzes and describes a new type of device: a ferrite-cored, variable gap, high-frequency power and data transfer system. The classic theoretical models existing in the literature for near-field communication (NFC) and WPT devices have foreseen a lumped-parameters characterization based on the representation of an equivalent circuit model (ECM). The strict interdependence between the different physical domains has clearly increased the difficulty in predicting the behavior of the device, due to the unwanted continuous and chaotic variation of the parameters. The proposed paper aims to provide a general and reliable multi-physics model based on the co-simulation of a Spice®-based ECM analysis and the ESRF Radia®-based 3D finite volume methodology (3DFVM), placing particular emphasis on the intrinsic sensitivity with respect to variables that cannot be directly controlled, such as the variation of the air gap between the coupled coils interfaces. Furthermore, this work outlines a detailed and effective experimental methodology for the estimation of static and dynamic electro-magnetic parameters and the validation of the numerical models in both the time and frequency domain, through the analysis of a real coupled WPT device.