Design investigation of electromechanical generator for energy harvesting

Abstract

In this paper designs of electromechanical generator for low frequency energy harvesting have been investigated. Simulation with finite element method has been conducted in order to determine highest output voltage of simple and robust generator consisting of permanent magnet and windings. In first part round magnets have been used in spherical and cylindrical form, benefiting from their ability to roll through winding with almost no mechanical friction inducing voltage in into windings. In the second part spindles with smaller radius than circumference of magnet were added to axis to increase rotational velocity of magnet in ambition to further increase induced voltage. As a result of added spindles and use of different magnet shapes length of winding turn varied and resistance of winding varied with it. To ensure similar conditions, windings have been recalculated to lowest electrical resistance using same fill factor, resulting in less winding turns decreasing induced voltage. In case of same kinetic energy input, higher rotational velocity combined with lower inertia produced higher induced voltage output.