Design and performance of a multimodal vibration-based energy harvester model for machine rotational frequencies

This paper presents the design of vibration-based energy harvester model whose resonance frequency can be tunable with the help of the various cantilever type beam structures: T-folded, E-folded without a tip mass, E-folded with one tip mass, and E-folded with two tip masses. The main contribution is to make an optimal structure that can scavenge the destructive vibration into the highest possible electric energy even the attached machine is running at a low rotational frequency. The finite element method and experimental verification were used to search for the optimal design that can make the operational bandwidth broader and yield the maximum power output. The results show that the design of E-folded with two tip masses can offer a first three resonance frequencies varied from 18.18 Hz to 26.8 Hz. Such a range of low frequency can well adopt the common range of rotational frequency of most of the rotary machines. From the observations of experiments, the maximum output of electricity could be guaranteed and harvested by an external circuit tailor-made for the beam structures.