Increasing viability of nonlinear energy harvesters by adding an excited dynamic magnifier

Abstract

Dynamic magnifiers and coupled harvester arrays are two strategies that have been developed over the past decade to improve the peak power and bandwidth of energy harvesters. However, both of these methods come with drawbacks. Dynamic magnifiers require retuning since they change the frequency of the peak response and some designs result in decreased power per unit mass. Coupled harvester arrays can increase the overall bandwidth, but also include central valleys between the peaks and a significant increase in the cost. This article describes an excited dynamic magnifier which borrows design characteristics from both traditional dynamic magnifiers and harvester arrays in order to overcome these drawbacks. A hardening-type nonlinear tuned energy harvester with excited dynamic magnifier can achieve higher peak power, greater power per unit mass, and wider bandwidth without the need for retuning and for a minimal added cost as compared to the uncoupled harvester. Most importantly, the addition of a dynamic energy harvester also significantly improves performance in the frequency range of coexisting solutions by expanding the basin of attraction for the larger amplitude solution.

Nonlinear Dynamic Analysis of Hybrid Piezoelectric-Magnetostrictive Energy-Harvesting Systems

“…Wang et al [20] use an arrangement with an auxiliary mass-spring magnifier to strengthen base excitation and deliver appropriate dynamic energy to overcome potential wells, hence leading to largeamplitude bistable motion. Bernard and Mann [21] merged the features of the dynamic amplifier and nonlinear modified energy-harvesting system to enhance the total harvesting bandwidth and improve the harvested power.…”

An Improved Magnetically Bistable Piezoelectric Energy Harvester

“…Both softening and hardening style nonlinear beam models have shown to provide a much wider usable frequency range than a single linear oscillator, but with lower maximum power output. The use of coupled beams [6] or dynamic magnifiers [7] have shown improved peak power performance, but another drawback of softening and hardening oscillators is that they have multiple stable equilibria and the high energy equilibrium is the most difficult to obtain experimentally.…”