Reflexive Field Containment in Dynamic Inductive Power Transfer Systems

Abstract

We present a new topology appropriate for “dynamic” wireless charging. Possible applications include charging of electric vehicles or robots moving in a large, predesignated area. We propose a system with a transmitter made from multiple coils commensurable with the moving receiver(s), and powered by a single inverter. The proposed system uses the reactance reflected by the receiver to automatically increase the field strength in coupled portions of the transmitter-receiver system, thus allowing efficient power transfer and adherence to electromagnetic field emission standards without complex shielding circuits, switches, electronics, and communication. The power transfer is at its peak when the transmitting and receiving coils approach their maximum coupling (as defined by the geometrical constraints of the system), resulting in improved system-level efficiency. The presented analysis is supported with simulations and experiments.