Multi-mechanism non-linear vibration harvester combining inductive and magnetostrictive mechanisms

In this study, we focus on developing a multi-mechanism energy harvester (MMEH) which combines magnetostrictive and inductive mechanisms with overall shape and size similar to AA battery. The multi-mechanism harvester was theoretically modeled, fabricated and experimentally characterized. The theoretical model combining analytical and FEM modeling techniques provides the system dynamics and output power for specific generator and magnetostrictive geometry at various source conditions. The prototype consisted of a cylindrical tube containing a magnetic levitation cavity where a center magnet oscillated through a copper coil. Magnetostrictive rods were mounted on the bottom and top cap of the cylindrical tube. In response to external vibrations, electrical energy was harvested from the relative motion between magnet and coil through Faraday's effect and from the magnetostrictive material through the Villari effect. The experimental results were compared to theoretical predictions for both mechanisms which showed reasonable agreement. The difference between model predictions and experiments are discussed in detail. The inductive mechanism generated 5.3 mW, 2.57 mW, 0.27 mW at 0.9 G, 0.7 G and 0.4 G respectively.