Numerical Modeling of Electromagnetic and Multi-point Impacts Stoppers Coupling for Low Frequency Energy Harvesting

Abstract

We presented an electromagnetic and three oscillators multi-impact coupling device for a broad bandwidth frequency energy harvesting. The energy harvesting was achieved from low vibrations with limited amplitudes and quite low frequencies that were about 1/10th of the resonance frequency in harvester. When an excitation frequency approaching the oscillators’ resonant frequency, at least one of the oscillators will impact on a stiffer structure resulting in a higher “equivalent stiffness” resulting a much broader bandwidth with impacts. The Lorentz force was found that acted to counteract the cantilever free tip causing complicated dynamic responses, and this force was acting as energy dissipation. The inclusion of the three mechanical oscillators made energy harvesting possible when the excitation vibrations at quite low frequency as long as the high frequency cantilever was kept at a distance to prevent the Lorentz force to dominate. More specifically, the inclusion of the three mechanical impact oscillators made energy harvesting efficiently when excitation vibrations were at low frequency 5-70 Hz bandwidth.