Experimental Duffing oscillator for broadband piezoelectric energy harvesting

Abstract

This paper presents an experimental piezoelectric energy harvester exhibiting strong mechanical nonlinear behavior. Vibration energy harvesters are usually resonant mechanical systems working at resonance. The resulting mechanical amplification gives an output power multiplied by the mechanical quality factor Q when compared to non-resonant systems, provided that the electromechanical coupling k 2 is high as well as the mechanical quality factor Q. However, increasing the Q value results in a narrowband energy harvester, and the main drawback is the difficulty of matching a given vibration frequency range to the energy harvester's resonance frequency. Mechanical nonlinear stiffness results in a distortion of the resonance peak that may lead to a broadband energy harvesting capability while keeping a large output power as for high Q systems.This paper is devoted to an experimental study of a Duffing oscillator exhibiting piezoelectric electromechanical coupling. A nonlinear electromechanical model is first presented including piezoelectric coupling, a nonlinear stiffness as for a Duffing oscillator, and an additional nonlinear loss term. Under harmonic excitation, it is shown that for a particular excitation range, the power frequency bandwidth is multiplied by a factor of 5.45 whereas the output power is decreased by a factor of 2.4. In addition, when compared to a linear system exhibiting the same power bandwidth as for the nonlinear one (which is here 7.75%), the output power is increased by a factor of 16.5.Harmonic study is, however, partially irrelevant, because Duffing oscillators exhibit a frequency range where two stable harmonic solutions are possible. When excited with sine bursts or colored noise, the oscillator remains most of the time at the lowest solution. In this paper, we present a technique-called fast burst perturbation-which consists of a fast voltage burst applied to the piezoelectric element. It is then shown that the resonator may jump from the low solution to the high solution at a very small energy cost. Time-domain solution of the model is presented to support experimental data.

Nonlinear Hybrid Piezoelectric and Electromagnetic Energy Harvesting Driven by Colored Excitation

“…In general, different from previous studies for PE or EM energy harvester [32,35,37], nonlinearities generated by additional magnet interactions could be beneficial for hybrid PE and EM As shown in Figure 6, output performances based on analytical expressions of nonlinear hybrid piezoelectric and electromagnetic energy harvester are consistent with theoretical results through Energies 2018, 11, 498 13 of 23 solving 45 linearly coupled equations, the difference between modeling values obtained by two theoretical models is rather small. As a consequence, it demonstrates that it is feasible to predict output characteristics of nonlinear hybrid PE and EM energy harvester under colored excitation using the presented theoretical model again.…”

“…Daqaq et al [32] demonstrated that the expected value of the output power will decrease with the stiffness-type nonlinearity. After verification through numerical and experimental methods, Sebald et al [35,37] reached a similar conclusion for a Duffing-type PE oscillator under colored excitation. Nevertheless, the effects of introducing nonlinear stiffness into a randomly excited hybrid PE and EM energy harvester on output characteristics could be quite different.…”

“…In general, different from previous studies for PE or EM energy harvester [32,35,37], nonlinearities generated by additional magnet interactions could be beneficial for hybrid PE and EM energy harvesting because it lowers the natural frequency and provides more efficient transduction under colored excitation.…”

Nanoscale piezoelectric vibration energy harvester design

“…[15][16][17] Sebald et al 16 experimentally studied the harvested power and bandwidth of a PEH with nonlinearities in stiffness and damping and compared them with the performance of a linear PEH. The results showed significant improvements in the bandwidth and harvested power.…”

Regular and chaotic vibration in a piezoelectric energy harvester

“…Gammaitoni et al [8] and Masana and Daqaq [13] highlighted the advantages of a double well potential for energy harvesting, particularly when inter well dynamics were excited. The Duffing oscillator model has been used for many energy harvesting simulations, with the addition of electromechanical coupling for the harvesting circuit [14,15]. Electromagnetic harvesters with a cubic force nonlinearity have also been considered [16].…”