Near-field wireless power transfer for non-static applications

Wireless power transfer allows the transfer of energy from a transmitter to a receiver across an air gap, without any electrical connections. A wide range of possibilities exist to realize wireless power transfer. In this PhD, we focus on the near-field techniques that either use the magnetic field (inductive coupling) or the electric field (capacitive coupling) to transfer power wirelessly. The goal of this work is to improve the near-field wireless power transfer technology for applications that are non-static, i.e. with variable coupling, either due to vertical or lateral position changes. The emphasis is on the reciprocal wireless link itself, as well for inductive as for capacitive coupling. We pursue this improvement by two perspectives. First, we aim at improving the shape, dimensions and properties of the wireless link elements. For example, by changing the number of turns and shape of the transmitter coil, we can obtain a more homogeneous magnetic field, which is advantageous for inductive coupling applications where lateral position variation is a prerequisite. Secondly, we improve the necessary impedance matching and design of the wireless link. For variable coupling applications, a profound understanding of this interplay is necessary to optimize different types of power transfer systems, necessary for the design of an efficient system. Moreover, an 'optimized' system can have a different meaning, depending on the application. For example, for the wireless charging of biomedical implants, an optimized system can be the configuration that maximizes the amount of transferred power, whereas for the wireless charging of a smartphone or electric vehicles, the maximum efficiency configuration is more appropriate.status: publishe