Modeling Amorphous Ribbons in Energy Harvesting Applications

This paper describes an approach to an electromagnetic harvester exploiting the magnetostrictive properties of amorphous ribbons to generate an electromotive force upon time-varying stresses of vibrational origin. Alloys of composition Fe78B13Si9, thermally treated for maximum magnetic response to tensile stresses, are considered. A compact design is proposed, where the sensing core, a short bundle of few flux-closed amorphous strips subjected to a bias dc field, is connected at one end to a vibrating wall. A finite element calculation of the whole device under different resistive load conditions on the secondary circuit is made. It results into a power around 20 mu W/cm(3) per unit volume of core material delivered into the load at 100 Hz.