Low-frequency Piezoelectric Energy Harvester Research Articles

Performance Analysis of Low Frequency Piezoelectric Energy Harvesting Systems with Multiple Nonlinear Factors and Bidirectional Excitations

Performance Analysis of Low Frequency Piezoelectric Energy Harvesting Systems with Multiple Nonlinear Factors and Bidirectional Excitations

Energy stacking efficiency of a novel low-frequency spring-like piezoelectric energy harvester

Abstract This study introduces a novel approach to energy harvesting through a spring-like piezoelectric harvester, termed SPEH, specifically designed for extremely low-frequency excitations. Through the integration of PVDF films and incorporating multiple thin plastic layers, the experimental setup underwent testing across various impact amplitudes and loads. Notably, the results revealed that the height of the impact significantly influenced peak voltage generation, with a remarkable 74% surge observed between a 3-inch and a 1-inch impact under a 90g load. Conversely, the impact load exhibited a comparatively lesser influence on peak voltage. The analysis of generated RMS voltage demonstrated a consistent trend, where higher impact height and load weight correlated with increased RMS voltage, emphasizing the significance of system mass. This innovative approach seeks to harness ambient vibration energy for sustainable power generation, marking a stride in advancing low-frequency piezoelectric energy harvesting systems.

Low-Frequency Piezoelectric Energy Harvesting From Coupled Longitudinal–Transverse Vibration of Two Magnetic Coupling-Based Orthogonal Beams

Low-Frequency Piezoelectric Energy Harvesting From Coupled Longitudinal–Transverse Vibration of Two Magnetic Coupling-Based Orthogonal Beams

Dynamic modeling and experimental validation of a low frequency piezoelectric vibration energy harvester via secondary excitation of pressured fluid

A low frequency piezoelectric energy harvester using secondary excitation of pressured fluid is proposed in this paper to scavenge low frequency vibration energy in ambient environments. This harvester was characterized by an indirect vibration-to-electric energy converter via transferring the pressure energy of pressured liquid medium. A series of simulations and experiments were conducted to prove the good performance and the feasibility of this novel structure in low-frequency high-intensity vibration. The results showed that the diameter of damping orifice, initial system backpressure and proof mass brought strong influences on the resonance frequency and output voltage. Meanwhile, according to experiments, it was found that the resonance frequency was decreased with the decreasing liquid backpressure. In this case, lowest resonance frequency of 19 Hz was achieved under the condition of 10-kg proof mass and 0.2-MPa liquid backpressure. Also, there were the optimal proof mass and backpressure to maximize the generated voltage, respectively. Moreover, in the impedance matching experiments, the maximum output power reached 1.35mW at the matching load resistance of 18kΩ.

Design and Optimization of a Multimode Low-Frequency Piezoelectric Energy Harvester

In this paper, we present a microelectromechanical systems (MEMS)-based multimode low-frequency piezoelectric energy harvester (PEH), which can operate at low resonant frequencies (i.e., [Formula: see text][Formula: see text]Hz). The proposed harvester has a symmetric serpentine structure with a doubly clamped configuration comprising several proof masses at the junctions. The optimal parameters of the proposed energy harvester are determined by a computerized optimization technique based on a genetic algorithm (GA). Finite element simulations showed that the optimization results can generate high voltage with two usable low-frequency resonant frequencies. Furthermore, we discuss the array structure based on the proposed PEH. Finite element simulations demonstrate that our piezoelectric MEMS harvester array can generate voltage with a frequency ranging from 110.95 to 157.84[Formula: see text]Hz. Its normalized power density (NDP) when operating in the first four modes is 1284, 932, 1978, and 2592 [Formula: see text]Wcm−3 m−2s4, respectively, and its performance outperforms those of previously reported MEMS-based energy harvesters.

Effect of porous auxetic structures on low-frequency piezoelectric energy harvesting systems: a finite element study

Effect of porous auxetic structures on low-frequency piezoelectric energy harvesting systems: a finite element study

Performance improvement of low frequency piezoelectric energy harvester incorporating holes with an in-house experimental set-up

The piezoelectric energy harvesters can be an integral part of self-powered sensor system due to its compatibility with semiconductor technology. In this paper, a modified structural geometry has been proposed in order to improve the performance of energy harvesters with classical cantilever topology by incorporating through holes. A detail mathematical analysis has been carried out to manifest the effect of through hole on resonant frequency of piezo harvester using Rayleigh–Ritz method. The theoretical analysis is validated through simulation studies as well as experimental results. Accordingly, an in-house low cost experimental set-up has been developed using Polyvinylidinefluoride (PVDF) based macro-level energy harvester and loud speaker based vibration set-up. It has been observed that the resonant frequency is reduced from 26.23 Hz to 21.94 Hz due to incorporation of hole to classical cantilever for a given dimension. With input acceleration of 3.7 g, the developed macro-harvester set-up resonates at 23 Hz and is capable of producing power of 59.93 $$\mu$$ W with hole based structure whereas power of 14.60 $$\mu$$ W is obtained in case of without hole based structure. The macro-scale energy harvester with modified geometry has been also designed and simulated in finite element analysis method to validate the mathematical analysis and it is found that lower the resonant frequency higher the power obtained with the hole based topology. It is verified from the experimental, simulation and theoretical studies, that there is a dominant effect of through hole in the performance improvement of piezoelectric energy harvester.

Internal-field-dependent low-frequency piezoelectric energy harvesting characteristics of in situ processed Nb-doped Pb(Zr,Ti)O3 thin-film cantilevers

Piezoelectric thin-film-based cantilevers have been investigated for higher energy-harvesting performance with simplified processing steps. Here, a simple in situ film deposition process of heavily Nb-doped lead zirconate titanate (PZT) films, which does not require annealing and poling, has been demonstrated to verify the possibility of use of the resultant films as energy-harvesters specifically for low frequency vibrating sources. The in situ domain formation of the films during the deposition was demonstrated from the apparent shifts of the capacitance-electric field curves, indicating the presence of internal electric fields. The so-called imprint behavior was found to be directly related to the performance of piezoelectric energy harvesting. As an optimal example, 12 mol% Nb-doped cantilever harvesters that showed the largest imprint behavior exhibited the best values of ∼19.1 GPa figure-of-merit and ∼1436 μWcm−3g−2 power density, which are competitive compared to other reported values.

Improving low-frequency piezoelectric energy harvesting performance with novel X-structured harvesters

Vibration energy harvesting systems via an X-structure coupled with piezoelectric patches of special arrangements are investigated in this study. Two piezoelectric harvesters are specially installed on the X-shaped structure to explore potential benefits that the X-shaped structure could provide, and each piezoelectric pad has two layers composed of a polyvinyl chloride base patch and a micro-fibre composite patch. The theoretical analysis and experiment results indicate that the energy harvesting performance of the proposed novel arrangements of the piezoelectric harvesters can be enhanced especially in low-frequency range (below 10 Hz), compared with conventional cantilevered piezoelectric harvesters. More and higher energy harvesting peaks can be created and the effective harvesting frequency band can be obviously enlarged by expanding it to low-frequency range with the proposed methods. The X-structure-based generators can enable piezoelectric materials to harvest power from low-frequency vibration sources due to its advantages in designable equivalent nonlinear stiffness, which can be easily tuned by adjusting the key structural parameters. The design and results would provide an innovative solution and insight for smart piezoelectric materials to improve the energy harvesting efficiency in the low-frequency range including small-scale ocean wave power harvesting, human motion power and animal kinetic power harvesting, etc.

Low Frequency Piezoelectric Energy Harvesters Based on Pb-Free Thin Films

The successful utilization of Pb-free piezoelectric materials for the most useful cantilever-type energy-harvesters has been a critical interest for better performance. Here, we introduce the piezoelectric energy-harvesting characteristics of Bi0.5Na0.5TiO3-BaTiO3 (BNT-BT) thin films. The BNT-based thin films have not been reported so far for the energy-harvesting applications. 0.94BNT-0.06BT thin films, which are in the morphotropic phase boundary, showed the best dielectric and piezoelectric performance. The poling effect on the 0.94BNT-0.06BT thin films was also investigated by varying poling electric field, poling temperature and poling time. The 0.94BNT-0.06BT with poling process showed the improved piezoelectric constant of 3.13 C/m2 in the poling condition of 700 kV/cm, 60 oC and 20 min, compared to that of 3.04 C/m2 for films without poling process. XRD patterns showed the increased intensity of (002) peak indicating the increase in the volume fraction of the c-domain of BNT-BT film by applied external electric field, and thus the figure of merit (FOM) values were improved with increased poling field. As a result, the cantilever type energy harvester showed the output power of 2.22 µW from the vibration source with 42 Hz.

A low frequency piezoelectric energy harvester with trapezoidal cantilever beam: theory and experiment

With the development of low power MEMS device and outdoor wireless sensor network, new energy supply has been a key to replace the traditional energy which has some disadvantages. We have found that obtaining energy from the daily low frequency vibration environment is a very efficient solution to ease the pressure of energy sources. In this paper, a utility low frequency piezoelectric energy harvester with trapezoidal cantilever beam is presented. Then, a relevant theoretical model, optimization method and comparison experiment are made. The results show that the theoretical analysis results are in agreement with the experimental results; under the condition of constant beam length, open-circuit voltage and output power of the trapezoidal beam piezoelectric energy harvester are 81.6 and 167% more than those of the rectangular beam piezoelectric energy harvester. In addition, In order to further broaden the frequency band and improve output characteristics, we use the nonlinear method to redesign the experiment based on the above experiments. The results show that distance and magnet polarity change have an important effect on output characteristics.

Modelling and fabrication of a compliant centrally supported meandering piezoelectric energy harvester using screenprinting technology

This paper reports the design, simulation, fabrication, and experimental testing of a low-frequency piezoelectric energy harvester fabricated using screen-printing technology. A centrally supported meandering geometry is chosen to reduce the torsional mode effects during the unit vibrations and to achieve better power efficiency. The design experiences alternating stress along the beams and a strain-matching polarization technique is used to minimize voltage cancellation. The test results are validated against the finite element solution for which there is a good agreement.

A low frequency MEMS energy harvester scavenging energy from magnetic field surrounding an AC current-carrying wire

This paper reports on a low frequency piezoelectric energy harvester that scavenges energy from a wire carrying an AC current. The harvester is described, fabricated and characterized. The device consists of a silicon cantilever with integrated piezoelectric capacitor and proof-mass that incorporates a permanent magnet. When brought close to an AC current carrying wire, the magnet couples to the AC magnetic field from a wire, causing the cantilever to vibrate and generate power. The measured average power dissipated across an optimal resistive load was 1.5 μW. This was obtained by exciting the device into mechanical resonance using the electro-magnetic field from the 2 A source current. The measurements also reveal that the device has a nonlinear response that is due to a spring hardening mechanism.

Design of a Low Frequency Piezoelectric Energy Harvester for Rodent Telemetry

This work presents the design and simulation of a piezoelectric-based device to generate electrical power by harvesting the kinetic energy available from the natural movement of small animals, such as rodents. Telemetry acquisition from rodents is important in biomedical research, where rodent behavior data is used to study disease models, or in biology research, involving animal tracking. In both applications, a long-term powering scheme for telemetry electronics and radios is needed. A major challenge is the relatively small size and low frequency motion of rodents. The proposed energy harvester design is simulated and the results reported. The design consists of a cantilever beam with a piezoelectric layer, a proof mass, and motion limit pads. Its mass and size are intended for use with a rodent, to provide continuous power for monitoring without limiting rodent mobility. Maximum power is obtained when the excitation source (animal movement) frequency corresponds to the resonant frequency of the energy harvester. As well, we demonstrate that the harvester electrical impedance is important, and must match the impedance of the application circuit load, to maximize the electrical power harvested. An experiment is conducted to record typical rodent (mouse) running motion in three axes of acceleration. A power spectral density (PSD) was computed for all axes, and the highest power is observed in the x-axis (forward/backward) motion at a frequency of 11.7 Hz, which is the typical gait frequency. Hence, the proposed energy harvester has been specifically designed to resonate at 11.7 Hz. The response of the proposed design is simulated using finite element analysis (FEA) software, to predict the electrical power and proof mass displacement. The model is excited with both a pure sine wave, and also with an arbitrary waveform consisting of the actual displacement of the rodent movement. A multi-scale FEA meshing approach is used to accommodate the thin thickness and long length of the cantilever design using mapped meshes. Additionally, a transient simulation is used to simulate the proposed design with different applied excitation frequencies, to determine the ideal matched load impedance for maximum electrical power.

Low frequency piezoelectric energy harvesting at multi vibration mode shapes

A multi-degree of freedom micro-energy harvester has been designed, fabricated, and tested and sub 100Hz natural frequencies have been achieved. This design's resonant frequencies at its first three mode shapes are within the low ambient vibration frequency range. The structure is fabricated from a silicon substrate with Aluminum Nitride (AlN) energy harvesting elements on thin silicon beams and uses a chip as a proof mass. The nonlinear stiffness due to stretching strain in the structure provides a wider harvestable frequency bandwidth in each mode. The nonlinear load-deflection equation for the second mode shape of the device, which corresponds to vertical oscillation and maximum harvester deflection, has been modeled using finite element simulation. The first three natural frequencies of 71.8, 84.5, and 188.4Hz were measured experimentally for the presented harvester. A frequency bandwidth of 10Hz has been obtained for the second mode shape under a base excitation of 0.2g. A maximum open circuit voltage of 1V and power output of 136nW with a load resistance of 2MΩ have been measured using this harvester. Using a synchronized switch harvesting on inductor (SSHI) electrical interface and Lead Zirconate Titanate (PZT), simulations estimate that the power output could be improved to ∼3.1μW.

Investigation of folded spring structures for vibration-based piezoelectric energy harvesting

This paper presents a fixed-fixed folded spring as an alternative elastic element for beam-based piezoelectric energy harvesting. In order to harvest energy from low frequency vibration in an optimal manner, the natural/operational frequencies of harvesters must be reduced to match low frequency input vibrations. Therefore, natural frequency reduction of vibration-based energy harvesters is critical to maximize output power at low operational frequency. The mechanical optimization of cantilever-based piezoelectric energy harvesters is limited by residual stress-based beam curling that produced through microfabrication adding additional mechanical stiffness to the system. The fixed-fixed folded spring structure presented in this paper allows for increased effective beam length and residual stress relaxation, without out of plane beam curling to further reducing the natural frequency. Multiple designs of folded spring energy harvesters are presented to demonstrate the effect of important design parameters. It is shown that the folded spring harvesters were capable of harvesting electricity at low natural frequencies, ranging from 45 Hz to 3667 Hz. Additionally, the harvesters were shown to be insensitive to microfabrication-based residual stress beam curling. The maximum power output achieved by the folded spring harvesters was 690.5 nW at 226.3 Hz for a single harvesting element of an array, with a PZT layer thickness of 0.24 μm. The work presented in this paper demonstrates that the fixed-fixed folded spring can be used as a viable structural element for low frequency piezoelectric energy harvesting to take advantage of ambient vibrations found in low frequency applications.

Modeling, validation, and performance of low-frequency piezoelectric energy harvesters

Analytical and finite element electromechanical models that take into account the fact that the piezoelectric sheet does not cover the whole substrate beam are developed. A linear analysis of the analytical model is performed to determine the optimal load resistance. The analytical and finite element models are validated with experimental measurements. The results show that the analytical model that takes into account the fact that the piezoelectric patch does not cover the whole beam predicts accurately the experimental measurements. The finite element results yield a slight discrepancy in the global frequency and a slight overestimation in the value of the harvested power at resonance. On the contrary, using an approximate analytical model based on mode shapes of the full covered beam leads to erroneous results and overestimation of the global frequency as well as the level of harvested power. In order to design enhanced piezoelectric energy harvesters that can generate energy at low-frequency excitations, further analysis is performed to investigate the effects of varying the length of the piezoelectric material on the natural frequency and the performance of the harvester. The results show that there is a compromise between the length of the piezoelectric material, the electrical load resistance, and the available excitation frequency. By quantifying this compromise, we optimize the performance of beam–mass systems to efficiently harvest energy from a specified low frequency of the ambient vibrations.

A piezoelectric spring-mass system as a low-frequency energy harvester [Correspondence

We propose a new structure consisting of a piezoelectric spring-mass system as a low-frequency piezoelectric energy harvester. A theoretical model is developed for the system from the theory of piezoelectricity. An analysis is performed to demonstrate the low-frequency nature of the system. Other basic characteristics of the energy harvester, including the output power, voltage, and efficiency, are also calculated and examined.

Nonlinear output properties of cantilever driving low frequency piezoelectric energy harvester

Cantilever driving low frequency piezoelectric energy harvester (CANDLE) has been found as a promising structure for vibration energy harvesting. This paper presents the nonlinear output properties of the CANDLE to optimize the performance of the device. Simulation results of the finite element method illustrate that nonlinear contacts between the cymbal transducers and the cantilever beam are main reasons of the nonlinear output. However, high excitation acceleration of the nonlinear leap point limits the application of the device. Based on the simulation results and theory analysis, the excitation acceleration is reduced to 30 m/s2 by increasing the proof mass.

Low-frequency piezoelectric energy harvesting prototype suitable for the MEMS implementation

A low-frequency piezoelectric energy harvester based on impact vibration assembled with a compliant driving beam and two rigid generating beams is presented. The ambient low frequency is up-converted to high resonant frequency by the periodic impact between the driving beam and the generating beams. The advantages of the harvester are: restricting the large displacement of the compliant driving beam, improving power density and being especially suitable for a compact MEMS approach. The 1.53mW average power of the macroscale impact vibration harvester is achieved at 20.1Hz under 0.4g acceleration. The power density is 93.2μW/cm3, which is 6.8 times that of conventional counterpart (13.6μW/cm3). The measured results demonstrate the potential of the device applied to portable and implantable electronics benefited from the MEMS batch-fabrication technology.