Piezoelectric-based broadband bistable vibration energy harvester and SCE/SSHI-based high-power extraction

Abstract

This paper presents ambient mechanical vibrations as an alternative source for energy harvesting, especially beneficial where alternatives such as light, wind, biomass and thermal energy are limited, e.g., powering underground sensors. Transduction of ambient kinetic energy, e.g., the vibrations from thunder and field work, into electrical energy using piezoelectric generators has been investigated, utilizing a nonlinear bistable broadband piezoelectric harvester. A new model for the bistable piezoelectric harvester is suggested based on the standard Butterworth van Dyke model and its validity demonstrated through simulations. For efficient extraction of the transduced energy, we employ synchronous charge extraction (SCE) and parallel synchronized switch harvesting on inductor (SSHI). The switching in these circuits is implemented using a fully self propelled, low-power electronic breaker circuit, capable of detecting extrema in the input to perform switching. The power outputs from simulation of the bistable harvester have been presented, with the SCE and parallel SSHI providing respective average outputs of 78.51lW and 1251lW for a sinusoidal input of 0.326N at 10Hz applied to a 69.1 x 16.8 x 0.64 mm 3 cantilever (piezoelectric dimensions 35.56 x 14.48 x 0.2 mm 3 ). This shows significant gains over the harvested power reported in literature.

Coupled electromechanical analysis of MEMS-based energy harvesters integrated with nonlinear power extraction circuits

“…In the latter case the resonance frequency shift due to electromechanical coupling is neglected and the harvested energy is calculated only at the resonance of the system. Singh et al exploited these nonlinear switched techniques to improve the energy extraction from bi-stable harvesters (Singh et al 2014(Singh et al , 2015. Also research is continued on the effect of these nonlinear circuits in vibration damping of piezoelectric structures for vibration control purposes Yan et al 2016).…”

A broadband bistable piezoelectric cantilever-based vibration energy harvester with nonlinear high power extraction

“…Various extraction schemes for the piezoelectric generator have been proposed [48][49][50][51][52]. This section presents methods we have utilized to optimize power extraction from our nonlinear bistable transducer [29][30][31], and compares them to a standard extraction circuit comprising an AC to DC converter. Since the extracted energy is required to charge a battery, all circuits analyzed have a battery as the load.…”

“…The synchronous charge extraction (SCE) circuit [50,51], employed in our work [29][30][31], allows charge to build up on the piezoelectric capacitance C e until it reaches a maximum, corresponding to the maximum displacement of the cantilever. At this point, all the charge is extracted from the capacitor and transferred to the battery, thereby dropping the piezoelectric voltage to zero.…”

“…The parallel synchronized switch harvesting on inductor (SSHI) circuit [50,51], employed in our work [29][30][31], also involves switching at displacement extrema for synchronized extraction. Unlike SCE, however, the switch is turned on at the extrema to invert charge polarity on the piezoelectric capacitor, while the charge developed on C e flows to the battery during the rest of the period.…”

“…In order to maximize the energy transduced from broadband ambient vibrations, this work focuses on nonlinear harvesters. The first part of the work, presented in[29,30], makes the following Presents a completely mechanical way of increasing the bistable range of operation of the harvester, thus increasing efficiency, with close to zero energy cost; Extends the nonlinear Butterworth van Dyke model of the piezoelectric transducer with…”