Capacitive Wireless Power Transfer: a Matter of Materials

The mayor challenge in capacitive wireless power transfer is to master the low coupling capacitance that severely inhibits power density. The key to increase power density is the coupling between the transmitter and receiver of the system. In current literature, the coupling is described by an ideal pi model, where losses in the medium and its frequency dependent permittivity are not considered. While this model may be sound when air serves as the medium, does it hold for capacitive power transfer through solid media such as polymers?

This thesis leverages the common pi model, considering the dielectric frequency-dependent properties of media. To obtain this dielectric properties, an experimental laboratory setup is realised. This setup can automatically take measurements over distances from 1mm to 300mm for frequencies between 100 kHz and 20 MHz. Furthermore, this measurement data is incorporated into an optimised design of a CPT system. Based on analytical calculations, this optimised CPT system is constructed with the aim of transferring 100 W across distances from 1 mm to 10 mm through air and the solid media: glass, Epramid, Epratal, polycarbonate, PTFE, Multilene and Epratex. To achieve these requirements, an of the shelf gallium-nitride (GaN) inverter, a double sided LC-compensation network and four parallel copper plates, which are automatically height adjustable, are used. Moreover, the thesis also includes a section detailing the various pitfalls during the construction process, in particular inductor design or the electric breakthrough between the coupler plates.