Drastic bandwidth enhancement of bistable energy harvesters: study of subharmonic behaviors and their stability robustness

Thomas Huguet (1, 2) , Adrien Badel (2) , Olivier Druet (3) , Mickael Lallart (1)

1 LGEF - Laboratoire de Génie Electrique et Ferroélectricité
2 SYMME - Laboratoire SYstèmes et Matériaux pour la MEcatronique
3 EDPA - Équations aux dérivées partielles, analyse

In order to provide a serious alternative to chemical batteries for the energy supply of isolated sensors, bistable generators have been enthusiastically highlighted in recent years for their ability to harvest vibration energy on a wider frequency range compared to linear generators. Nevertheless, these bistable harvesters are generally characterized through a frequency sweep which does not reveal all the steady-state behaviors they can reach and therefore their full energy harvesting potential. Among such behaviors, subharmonic motions are hidden by this classical characterization and therefore had not received a lot of attention. This study proposes an original complete analytical analysis of subharmonic orbits for energy harvesting to predict their contribution to the global bandwidth of bistable generators. In addition, a new criterion, referred as stability robustness, is introduced to estimate the sensitivity of those behaviors to disturbances of different levels, allowing to finely and accurately estimate suitable behaviors for energy harvesting purposes in realistic conditions (behaviors easy to reach and maintain in time). Experimental results conducted with a buckled beams based electromagnetic generator confirm the pertinence of this criterion showing good agreement with the analytical predictions. Subharmonic behaviors finally appears, both theoretically and experimentally, to be of significant interest, as exploiting them leads to a 180 % increase of the global operating frequency range of the considered bistable energy harvester, for which more than 100 µW are generated on a 70 Hz bandwidth at 0.5 g.

Mots clés: Bistable; Nonlinear; Energy harvesting; Vibration; Subharmonic; Robustness

Domaines: Sciences de l'ingénieur [physics]

Thomas Huguet, Adrien Badel, Olivier Druet, Mickael Lallart. Drastic bandwidth enhancement of bistable energy harvesters: study of subharmonic behaviors and their stability robustness. Applied Energy, 2018, 226, pp.607 - 617. ⟨10.1016/j.apenergy.2018.06.011⟩. ⟨hal-01901836v1⟩