A Magnetostrictive Electric Power Generator for energy harvesting from traffic: Design and experimental verification

In the last decades, the growth in energy demand, the decrease of fossil fuels available in the market and the impact of anthropogenic factors on climate change has given new impulse to research on renewable energy systems, particularly those known as energy harvesting devices (EHDs) [1]. A large number of EHDs have been proposed, using different operating principle [1-4]. Among them, piezoelectric and magnetostrictive seem to be particularly suitable for the application in EHD. In these materials the application of external mechanical stress induces a change in the level of magnetization and therefore an electromotive force (emf) can be generated and collected in order to produce electrical energy. In magnetostrictive materials this effect has been theoretically and experimentally confirmed in metglas [5], Terfenol D [2,3], FeGa and several other alloys. In this article the magnetostrictive material considered is Terfenol D. In particular, we present a device, built using Terfenol D rods, able to convert the energy contained in mechanical stress generated by a passing vehicle on a speed bumps. The presented system (Speed Bumps Magnetostrictive Electric Power Generator — SBMEPG) can reduce the vehicle speed, producing electric energy and increasing road safety at the same time [6,7].