Modeling and characterization of permendur cantilever beam for energy harvesting

This article presents the development of a cantilever harvester made of permendur with tip excitation. In the beginning, the dynamic behavior of the tip-mass beam harvester subjected to a harmonic bending force at the free-end has been studied. Also, the magneto-mechanical model, rotating unbalance equations and Faraday's Law have been combined to present the general model for generated power. Furthermore, damping coefficients have been elaborately measured and considered in the modeling of magnetostrictive harvester and prediction of optimum load to generate the maximum power. Good agreement between analytical and experimental results shows that the model is able to predict the behavior of harvester under the vibration with tip excitation and can find the optimum external load to have maximum power. Experiment results show that the maximum output power is 6.81 μW/cm³ and this power happens when the harvester is connected to a 0.63 Ω external load. Compared to other magnetostrictive harvesters, Permendur shows lower power density. However, its harvested power is enough to energize μW electrical devices at a reasonable cost. The presented results in this paper can be utilized as a design guideline for future investigations to optimize vibration-based magnetostrictive energy harvesters with tip excitation.