Trådlös energiöverföring via elektromagnetisk induktion

Abstract

This paper describes a method for wireless energy transfer via near-field electromagnetic induction that is inexpensive, simple and can be applied to almost any type of system, regardless of size and energy demands. The method uses a primary unit consisting of an oscillator, amplifier and inductive coil that transfers energy to a secondary unit consisting of a coil, rectifier and voltage regulator. Two types of oscillators and several amplifier designs were realized and evaluated together with a multitude of flat coils of both monofilar and bifilar type. The results show that it is important to use an oscillator whose frequency is dependent on the inductance of the connected transmission coil, such as the Colpitts oscillator. This is preferable to an oscillator with a preset frequency, such as a Schmitt-trigger oscillator.