Modeling and Optimization of Innovative Energy Harvesters

Abstract

Extracting wind energy via piezoelectric transduction is emerging as a potential alternative to conventional batteries in portable and wireless gadgets. To harvest the vibrational energy due to wind, different phenomenon like galloping, vortex-inducedvibrations (VIV) or flutter can be used depending upon the shape of the attached cylinder however, base acceleration can be added to any such phenomenon to create hybrid excitation. The performance efficiency of such a hybrid energy harvester greatly depends on the base excitation specially when the harvester can switch between the monostable and bistable configurations due to nonlinear magnetic force hence there is a need to further explore this aspect. In this study, the energy harvester's efficiency has been systematically compared in both monostable and bistable configurations while working under base excitation. The model can be easily extended to allow the addition of the wind in any phenomenon like galloping or VIV. A pair of magnets have been added to incorporate the nonlinear magnetic force that is capable to buckle the beam depending upon the distance between the magnets. To make the comparison meaningful, the system's performance has been compared in both monostable and bistable configurations at same coupled frequency. A distributed parameter model was established by using the Euler-Lagrange method. Nonlinear magnetic force is represented using dipole-dipole representation, while a reduced order model has been developed using Galerkin discretization. After that static and frequency analyses, performance comparison in both monostable and bistable configurations is presented at same coupled frequency