Power Efficiency of Energy Harvester Driven by Harmonic Excitation with Amplitude Perturbation

Krzysztof Kucab,Grzegorz Górski

doi:10.1155/2019/8564346

Abstract

In this paper, we examine the influence of the background’s stochastic excitations on an output power generated by using an energy harvester. The harvester is composed of two magnets attached to a piezoelastic oscillators separated by a distance Δ from the static magnets fastened directly to the device. We also introduce the parameter α which describes the mass ratio of moving magnets. We examine the output power for different excitation frequencies, different values of α, and different amplitudes δ0 of the stochastic force. We also analyze the influence of δ0 and Δ on the effective output power (EOP), the mean value of output power averaged over the considered frequencies, produced by using the harvester. We have observed that increasing δ0 causes the growth of generated mean power, especially in the low-frequency regime, while the maximum power near the resonance frequency remains unchanged. The EOP also grows with increasing δ0 for all examined values of α. The environment’s stochastic behavior improves slightly the harvester’s efficiency as compared to the purely harmonic case. Analyzing the dependence of EOP on Δ, we observed the maximum which appears at values of Δ corresponding to the situation when the system starts to work in the unsynchronized regime.

Highlights

In the world of modern electronic devices which are characterized by very low-power consumption, the energy harvesting devices seem to be very important and useful energy sources, especially in vibrating, hard to reach environments [1,2,3,4]
We have examined the electric power generated by using the energy harvesting device attached to a vibrating source in the case when harmonic excitations are mixed with the stochastic ones. e obtained results were compared to the harmonic case. e bistability of the system was achieved by the relatively small distance between moving and stable magnets (Δ 5 mm), so the harvester worked mostly in the nonlinear regime
Increasing the amplitude δ0 of the stochastic force, we have observed the growth of generated mean output power P, especially in the low-frequency regime

Summary

Introduction

In the world of modern electronic devices which are characterized by very low-power consumption, the energy harvesting devices seem to be very important and useful energy sources, especially in vibrating, hard to reach environments [1,2,3,4]. One should take into account that an energy harvesting devices should be adapted to environments which are characterized by a broad frequency band In this case, the harvesters should relatively produce large power [5]. To extend the frequency range where the generated effective output power is relatively high, one should use the nonlinear systems. Mann and Sims [6] have shown that the use of magnetic levitation in energy harvesters allows for the nonlinear system to extend the frequency bandwidth. Is work is based on the model described in our previous papers [12, 24], where we have analyzed the electrical power generated by using the energy harvesting device subjected to the harmonic excitations only. We extend the previous approach for the stochastic behavior of the background vibrations

Materials and Methods

Results and Discussion

Conclusions

Disclosure