Bandwidth Broadening of Piezoelectric Energy Harvesters Using Arrays of a Proposed Piezoelectric Cantilever Structure

Abstract

One of the most important challenges in the design of the piezoelectric energy harvester is its narrow bandwidth. Most of the input vibration sources are exposed to frequency variation during their operation. The piezoelectric energy harvester’s narrow bandwidth makes it difficult for the harvester to track the variations of the input vibration source frequency. Thus, the harvester’s output power and overall performance is expected to decline from the designed value. This current study aims to solve the problem of the piezoelectric energy harvester’s narrow bandwidth. The main objective is to achieve bandwidth broadening which is carried out by segmenting the piezoelectric material of the energy harvester into n segments; where n could be more than one. Three arrays with two, four, and six beams are shaped with two piezoelectric segments. The effect of changing the length of the piezoelectric material segment on the resonant frequency, output power, and bandwidth, as well as the frequency response is investigated. The proposed piezoelectric energy harvesters were implemented utilizing a finite element method (FEM) simulation in a MATLAB environment. The results show that increasing the number of array beams increases the output power and bandwidth. For the three-beam arrays, at n equals 2, 6 mW output power and a 9 Hz bandwidth were obtained. Moreover, the bandwidth of such arrays covered around 5% deviation from its resonant frequency. All structures were designed to operate as a steel wheel safety sensor which could be used in train tracks.

Design and Development of a Lead-Freepiezoelectric Energy Harvester for Wideband, Low Frequency, and Low Amplitude Vibrations

“…According to the literature [45], connecting different energy harvesting cantilever beams of the same thickness but with different lengths, can produce higher output power. It was reported that the output power was increased from 2 µW to 5 µW, and the bandwidth was widened from (47, 55) Hz to (22,88) Hz. Therefore, in this study, we decided to use the same thickness but different length cantilevers.…”

“…In the literature, the piezoelectric effect is among, if not the first, most employed principle in the field of mechanical micro energy conversion [13][14][15]. Based on the "direct piezoelectric effect" phenomenon that is also employed in sensors [16] and self-sensing actuators [17,18] for further feedback control [19][20][21][22], piezoelectric energy harvesting devices can scavenge the energy from vibrations and motion present in the surroundings to provide the maximum output voltage when operating at their resonance frequencies. However, exciting the devices at their resonance frequencies is challenging because the available surrounding frequency is generally low whilst the resonance of the harvester's structure is high.…”

Adaptive tracking control of a new nonlinear energy harvester system based on the cantilever beam structure

“…Piezoelectric transductions commonly consist of a cantilever beam on which one or more piezoelectric are embedded. For example, in Salem et al (2021), a single-beam piezoelectric cantilever structure has been investigated, in which to achieve a fixed output power and bandwidth, the total length of piezoelectric material and the cantilever beam length of the structure have been set to constant values. In Borowiec (2015), an energy harvester system is proposed, which consisted of a cantilever beam with a tip mass and piezoelectric patches.…”

A Linear-Arc Composite Beam Piezoelectric Energy Harvester Modeling and Finite Element Analysis

“…Wang [25] determined the relationship between the thickness of the beam and the output power of the energy harvester through theory and experiments. Salem [26] divided the piezoelectric material of the straight beam piezoelectric energy harvester into n segments to widen the frequency and improve the output power.…”