Harvesting vibration energy using nonlinear oscillations of an electromagnetic inductor

Abstract

Harvesting energy from ambient vibration is a promising method for providing a continuous source of power for wireless sensor nodes. However, traditional energy harvesters are often derived from resonant linear oscillators which are capable of providing sufficient output power only if the dominant frequency of input vibrations closely matches the device resonant frequency. The limited scope of such devices has sparked an interest in the use of nonlinear oscillators as mechanisms for broadband energy harvesting. In this study, we investigate the harvesting performance of an electromagnetic harvester sustaining oscillations through the phenomena of magnetic levitation. The nonlinear behavior of the device is effectively modeled by Duffing's equation, and direct numerical integration confirms the broadband frequency response of the nonlinear harvester. The nonlinear harvester's power generation capabilities are directly compared to a linear electromagnetic harvester with similar dynamic parameters. Experimental testing shows that the presence of both high and low amplitude solutions for the nonlinear energy harvester results in a tendency for the oscillator to remain in a low energy state for non-harmonic vibration inputs, unless continuous energy impulses are provided. We conclude by considering future applications and improvements for such nonlinear devices.

Survey of electromagnetic and magnetoelectric vibration energy harvesters for low frequency excitation

“…A design study made by Lee et al in 2010 uses a cylindrical magnets as presented in figure 7 (a) [21]. Two magnets are fixed to either end of the tube.…”

Vibration energy harvesting using the nonlinear oscillations of a magnetostrictive material

“…The transducer response tends to drop into and remain in a low-amplitude response state corresponding to the two stable, steady-state, periodic responses characteristic of the hysteresis region of Duffing-type oscillators. 7 In comparison, multi-degree-of-freedom systems that have natural frequencies related in (near) integer ratios have been shown to have the potential to exhibit single, large amplitude response to primary harmonic excitation over an extended frequency range. One specific example is an L-shaped beam configured so that the lowest two natural frequencies are related in an (approximately) 2:1 ratio.…”

“…The dynamic response of one type of electromagnetic harvester 6,7,8 can be well described by Duffing-type equations. Under single-frequency harmonic excitation, these devices can harvest energy over a range a frequencies.…”

Enhanced vibration energy harvesting using nonlinear oscillations

“…Even machinery, typically operating at a single-dominant frequency, will have energy content distributed over a range of frequencies. Energy harvesters whose transducers are governed by nonlinear equations of motion have been shown [8][9][10] to scavenge energy over a broader frequency range in comparison. Multi-degree-of-freedom systems that have natural frequencies that are related in (near) integer ratios, referred to as internal resonance, have been demonstrated to have the potential to exhibit large amplitude response to primary excitation [11][12] .…”