Design Of Piezoelectric Energy Harvester Research Articles

Roadway piezoelectric energy harvester design considering electrical and mechanical performances

Piezoelectric energy harvesting is an efficient technique among energy scavenging methods employed in asphalt pavements. Several designs are reported in the literature; however, what is less discussed is how to design the harvester. In this paper, a fixed volume of piezoelectric material is considered, and various design parameters are discussed in order to achieve an improved design. The main objective is to enhance the harvester performance, considering electrical and mechanical aspects, simultaneously. The output power, the level of induced stress on the piezoelectric material, the endurance limit, and the coupling effect of the device with the pavement are considered. As a case study, the finite element model of a piezoelectric harvester is developed and validated with the experimental results. A parametric study is then carried out in order to improve both the electrical and mechanical characteristics of the device. Various parameters, such as piezoelectric disks cross-section, piezoelectric material, as well as the disks aspect ratio are considered. The proposed structures are compared with similar ones reported in the literature and show higher output powers of 3 − 5.8 times. A case study is presented to show the signal conditioning process of the harvested power for practical applications. Improvements in various aspects of the device performance, while considering the economic aspects, i.e., the amount of consumed piezoelectric material, show the effectiveness of the proposed method.

Broadband power generation of piezoelectric vibration energy harvester with magnetic coupling

In this work, a magnetic coupling 2-degree-of-freedom bistable piezoelectric energy harvester was designed and developed. The device consisted of a primary beam with a magnet attached to the tip and a parasitic beam. The magnets between the primary beam and the pedestal generated nonlinear repulsive force. By controlling the distance between two magnets, the system could oscillate between two stable equilibrium points which allowed the device to exhibit broadband characteristics. Theoretical and experimental investigations of this energy harvester were presented over a range of excitation frequencies. Lumped-parameter nonlinear equations of the bistable Duffing oscillator with magnetic coupling were introduced to describe the broadband voltage response. Compared with the theoretical results, at an excitation acceleration of 3 m/s2, it is experimentally verified that the proposed device achieved the operation frequency bandwidth adding up to 8 Hz at around the first and second resonance regions which was about 2.7 times higher than conventional 2-degree-of-freedom linear harvester one. In addition, energy harvesting efficiency could be improved by increasing the frequency bandwidth. The results of this work can be applied to optimize the design of piezoelectric energy harvester and harvest low-frequency vibration energy in the environment to supply power for sensor network nodes.

A methodology for topology optimization based on level set method and its application to piezoelectric energy harvester design

A methodology for topology optimization based on level set method and its application to piezoelectric energy harvester design

Optimized energy harvesting through piezoelectric functionally graded cantilever beams

The emergence of piezoelectric functionally graded materials (PFGMs) has sparked the present research interests toward their energy harvesting behaviors. This paper theoretically investigates the optimized energy harvesting characteristics of PFGM cantilever beams under harmonic excitation. The electromechanical coupling governing equations are formulated based on Euler–Bernoulli beam theory, and utilizing the Galerkin discretization yields the frequency-response relations of the voltage, current, and power parameters, and the analytical optimal resistance as well. The present theoretical model is validated by comparing with the experimental results in literature, and parametric studies are addressed to discuss the effects of the damping ratio, the inhomogeneous parameter of PFGMs and the electrical resistance on the structural responses. More importantly, the optimized energy harvesting characteristics of PFGM cantilever beams are captured during discussions on the optimal conditions of the frequency-ratio and the electrical resistance. Results reveal that the superiority of PFGM energy harvesters over the conventional piezoelectric laminate ones, basically, lies in the design toward constituent distribution of PFGMs enabling the control over the energy harvesting efficiency. Specifically, provides that both the optimal frequency-ratio and the optimal resistance hold simultaneously, there would be a critical value for the inhomogeneous parameter, which can be utilized to maximize the energy harvesting efficiency for PFGM beams. The present work may support the prospective material gradient design of piezoelectric energy harvesters.

Modeling and Efficiency Analysis of a Piezoelectric Energy Harvester Based on the Flow Induced Vibration of a Piezoelectric Composite Pipe.

This paper proposes and investigates a piezoelectric energy harvesting system based on the flow induced vibration of a piezoelectric composite cantilever pipe. Dynamic equations for the proposed energy harvester are derived considering the fluid-structure interaction and piezoelectric coupling vibration. Linear global stability analysis of the fluid-solid-electric coupled system is done using the numerical continuation method to find the neutrally stable vibration mode of the system. A measure of the energy harvesting efficiency of the system is proposed and analyzed. A series of simulations are conducted to throw light upon the influences of mass ratio, dimensionless electromechanical coupling, and dimensionless connected resistance upon the critical reduced velocity and the normalized energy harvesting efficiency. The results provide useful guidelines for the practical design of piezoelectric energy harvester based on fluid structure interaction and indicate some future topics to be investigated to optimize the device performance.

Piezoelectric Buckled Beam Array on a Pacemaker Lead for Energy Harvesting

AbstractSelf‐sustainable energy generation represents a new frontier to significantly extend the lifetime and effectiveness of implantable biomedical devices. In this work, a piezoelectric energy harvester design is employed to utilize the bending of the lead of a cardiac pacemaker or defibrillator for generating electrical energy with minimal risk of interfering with cardiovascular functions. The proposed energy harvester combines flexible porous polyvinylidene fluoride–trifluoroethylene thin film with a buckled beam array design for potentially harvesting energy from cardiac motion. Systematic in vitro experimental evaluations are performed by considering complex parameters in practical implementations. Under various mechanical inputs and boundary conditions, the maximum electrical output of this energy harvester yields an open circuit voltage (peak to peak) of 4.5 V and a short circuit current (peak to peak) of 200 nA, and that energy is sufficient to self‐power a typical pacemaker for 1 d. A peak power output of 49 nW is delivered at an optimal resistor load of 50 MΩ. The scalability of the design is also discussed, and the reported results demonstrate the energy harvester's capability of providing significant electrical energy directly from the motions of pacemaker leads, suggesting a paradigm for biomedical energy harvesting in vivo.

A Wideband Piezoelectric Energy Harvester Design by Using Multiple Non-Uniform Bimorphs

This paper presents an analytical approach for the development of a new wideband piezoelectric energy harvesting system. The proposed model is based on Adomian decomposition method to derive the dynamic response of the general non-uniform smart structures under external environmental excitations over a wide frequency domain efficiently harvesting the subsequent vibrational energy. The steady-state response of a nonlinearly tapered piezoelectric harvester subjected to harmonic base motion is obtained, and the higher potential electromechanical outputs compared with traditional uniform harvester are analytically derived. Afterward, a group of nonlinearly tapered cantilevers with the same volume and length but different taper ratios and surface bonded piezoelectric layers are assembled together in order to build a broadband piezoelectric energy harvester. Through numerical studies, it is proven that with the proposed non-uniform configuration, the new energy harvester design can function effectively and efficiently with high voltage output over a wide frequency range. The designed wideband harvester can automatically activate one of the non-uniform bimorphs to resonate at particular ambient vibration frequencies and eventually reach the maximum electromechanical output. Based on the proposed theoretical model, an optimum structural design for the wideband piezoelectric energy harvester in the required operational frequency range can be efficiently achieved.

Design and analysis of high output piezoelectric energy harvester using non uniform beam

ABSTRACTAmong the energy harvesting techniques, design of piezoelectric energy harvesters using cantilever beam is popular. In this paper two different structurally tailored cantilever based piezoelectric energy harvesters are proposed to improve the harvested power. In the first design, the harvester consists of rectangular section from the root followed by a tapered section (RTCB) and in the second type tapered section followed by rectangular section (TRCB). These harvesters are associated with a piezoelectric patch to achieve higher power by means of connecting the uniform width of rectangular section to the width tapered beam having tapering ratio β towards its free end. It is also proposed to introduce a rectangular cavity in the above energy harvesters to further maximize the harvester voltage. The mode shapes and fundamental natural frequency of proposed energy harvesters are obtained analytically by using Euler-Bernoulli beam theory and its free vibration solution is analyzed by using Bessel functions. The performance of the proposed energy harvesters is demonstrated through both analytical and experimental implementation. Harvester TRCB increases the harvester voltage by 91.3% and 76.9% respectively as compared to the energy harvester considered with uniform cantilever beam. Among all the energy harvesters projected during this paper, the maximum voltage is produced from the TRCB harvester with rectangular cavity.

A new broadband energy harvester using propped cantilever beam with variable overhang

Design of piezoelectric energy harvester for a wide operating frequency range is a challenging problem and is currently being investigated by many researchers. Widening the operating frequency is required, as the energy is harvested from ambient source of vibration which consists of spectrum of frequency. This paper presents a new technique to increase the operating frequency range which is achieved by designing a harvester featured by a propped cantilever beam with variable over hang length. The proposed piezoelectric energy harvester is modeled analytically using Euler Bernoulli beam theory and the effectiveness of the harvester is demonstrated through experimentation. The results from analytical model and from experimentation reveal that the proposed energy harvester generates an open circuit output voltage ranging from 36.43 V to 11.94 V for the frequency range of 27.24 Hz to 48.47 Hz. The proposed harvester produces continuously varying output voltage and power in the broadened operating frequency range.

Design of high output broadband piezoelectric energy harvester with double tapered cavity beam

Design of piezoelectric energy harvester for a wide operating frequency range is a challenging problem and is currently being investigated by many researchers. Widening the operating frequency is required, as the energy is harvested from ambient source of vibration which consists of spectrum of frequency. This paper presents a technique to increase the operating frequency range and to enhance the amplitude of the generated voltage in the operating frequency range. The wider operating frequency range is achieved by designing a harvester using propped cantilever beam with variable overhang and the amplitude of the generated voltage is enhanced by introducing a double tapered cavity. The proposed piezoelectric energy harvester is modeled analytically using Euler Bernoulli beam theory. The results from the modeling and analysis reveal that the maximum voltage is generated from the energy harvester designed with the double tapered cavity having the taper angle of α = 2.25°. Hence the experimental investigations are carried out with this energy harvester and the generated voltage measured is in close agreement with the results obtained from the model. The simulation and experimental results presented in this paper demonstrate that the proposed harvester design not only widens the operating frequency range but also it enhances the amplitude of the generated voltage in large extent.

Advanced Model for Fast Assessment of Piezoelectric Micro Energy Harvesters

The purpose of this work is to present recent advances in modelling and design of piezoelectric energy harvesters, in the framework of Micro-Electro-Mechanical Systems (MEMS). More specifically, the case of inertial energy harvesting is considered, in the sense that the kinetic energy due to environmental vibration is transformed into electrical energy by means of piezoelectric transduction. The execution of numerical analyses is greatly important in order to predict the actual behaviour of MEMS devices and to carry out the optimization process. In the common practice, the results are obtained by means of burdensome 3D Finite Element Analyses (FEA). The case of beams could be treated by applying 1D models, which can enormously reduce the computational burden with obvious benefits in the case of repeated analyses. Unfortunately, the presence of piezoelectric coupling may entail some serious issues in view of its intrinsically three-dimensional behaviour. In this paper, a refined, yet simple, model is proposed with the objective of retaining the Euler-Bernoulli beam model, with the inclusion of effects connected to the actual three-dimensional shape of the device. The proposed model is adopted to evaluate the performances of realistic harvesters, both in the case of harmonic excitation and for impulsive loads.

Up-scaled macro-device implementation of a MEMS wideband vibration piezoelectric energy harvester design concept

In this work, we discuss a novel mechanical resonator design for the realisation of vibration Energy Harvester (EH) capable to deliver power levels in the mW range. The device overcomes the typical constraint of frequency narrowband operability of standard cantilevered EHs, by exploiting a circular-shaped resonator with an increased number of mechanical Degrees Of Freedom (DOFs), leading to several resonant modes in the range of vibrations of interest (i.e. multi-modal wideband EH). The device, named Four-Leaf Clover (FLC), is simulated in Ansys Workbench™, showing a significant number of resonant modes up to vibrations of around 2 kHz (modal eigenfrequencies analysis), and exhibiting levels of converted power up to a few mW at resonance (harmonic coupled-field analysis). The FLC mechanical structure, along with cantilevered test structure, is realised by micro-milling of an Aluminium foil. PolyVinyliDene Fluoride (PVDF) film sheet pads are assembled in order to collect first experimental feedback on generated power levels. The FLC and cantilevered EH test structures are characterised experimentally with a measurement setup purposely developed, showing encouraging performance related to the technology chosen for the realisation of EH, thus paving the way for full validation of the macro-FLC concept.

Nonlinear analysis and power improvement of broadband low-frequency piezomagnetoelastic energy harvesters

A significant impediment to the deploy- ment of vibration-based energy harvesting devices has been the limitation of most low-frequency transduc- ers, usually in the form of unimorph or bimorph can- tileverbeam,toextractenergyfromaverynarrowband- width around the transducer's fundamental frequency. In such devices, a slight deviation from the fundamen- tal frequency causes a significant reduction in the level of harvested power by several orders of magnitudes. Additionally,mostofthecurrentresearcheffortsonthe design of piezoelectric energy harvesters have had lim- ited success in achieving low resonance frequency. To overcome these challenges, we introduce an enhanced broadband low-frequency piezomagnetoelastic energy harvester. This harvester consists of a partially cov- ered piezoelectric cantilever beam with a fixed magnet mass at the top of the magnet tip mass. A nonlinear distributed-parameter model based on Euler-Bernoulli beam theory and Galerkin discretization is developed. This electromechanical model is validated with previ- ous experimental measurements for a specific value of the spacing distance between the two magnets. A para- metric study is performed to determine the effects of the spacing distance between the two magnets on the static position of the harvester, natural frequency, and level of the harvested power. It is demonstrated that a decrease between the two attractive magnets results in a decrease in the natural frequency of the harvester withastrongsofteningbehaviorwhichgivestheoppor- tunity to harvest energy at broadband low-frequency range. The results also show that the presence and importance of the softening behavior depends on the electrical load resistance. In conclusion, the results show that depending on the available low excitation frequency, an enhanced piezoelectric energy harvester can be tuned and optimized by changing the spacing distance between the two tip magnets.

Simulation and experimental demonstration of improved efficiency in coupled piezoelectric cantilevers by extended strain distribution

A piezoelectric energy harvester design is proposed, which will achieve a wider bandwidth without compromising energy conversion efficiency for future use in e g gas turbines. By coupling two cantilevers where the tip of the bottom one is attached to the base of the upper one, the harvester will have a wider bandwidth and a higher power output compared to two optimally tuned single cantilevers, which to a large part is the effect of an extended strain distribution in the bottom cantilever in the coupled configuration. The design is compact, using only half the area compared to two parallel single cantilevers at the price of only a small increase in height. The coupled harvester displays approximately five times higher power output than two tuned single cantilevers.

Modelling and experimental verification of more efficient power harvesting by coupled piezoelectric cantilevers

A new piezoelectric energy harvester design is proposed in order to achieve a wider bandwidth without compromising energy conversion efficiency. By coupling two cantilevers where the tip of the bottom one is attached to the base of the upper one, the simulated harvester will have a wider bandwidth and higher power output compared with two simulated single tuned single cantilevers. This is a compact design, using only half the area compared to two parallel single cantilevers at the price of a small increase in height. The measured coupled harvester has approximately 1.7 times higher energy output than the combination of two measured tuned single cantilevers achieved by a coupling with less mechanical damping. With an improved coupling the power output is increased to 2.3 times higher than two single tuned cantilevers.

A novel piezoelectric energy harvester designed for single-supply pre-biasing circuit

In this paper, the design and test of a novel screen printed piezoelectric energy harvester for the single-supply pre-biasing (SSPB) circuit is presented. It was demonstrated previously that by using the SSPB circuit, power delivered to the load was over three times greater than that in the case of using a bridge rectifier circuit. For maximum power extraction from energy harvesters using the SSPB circuit, the SSPB switches must be triggered when the piezoelectric beam reaches its maximum point of displacement. These points coincide with the peaks and troughs of the voltage across the piezoelectric material, thus accurate peak detection is required. A new design of piezoelectric energy harvester was presented to integrate a sensing piezoelectric component with the main piezoelectric layer for energy harvesting. Maximum power generation by SSPB requires the sensing voltage to be in phase with the generating voltage in order to correctly detect the peaks. However, the difference in areas between the sensing piezoelectric component and the energy harvesting piezoelectric component leads to a difference in capacitance that causes phase shift between the two signals. To overcome this issue, impedance matching was performed. Simulations and experimental rests were presented.

Investigation on MEMS-based Piezoelectric Energy Harvester Design with Aspect of Autonomous Automobile Sensors

Investigation on MEMS-based Piezoelectric Energy Harvester Design with Aspect of Autonomous Automobile Sensors

Design of piezoelectric energy harvesting devices subjected to broadband random vibrations by applying topology optimization

Converting ambient vibration energy into electrical energy by using piezoelectric energy harvester has attracted a lot of interest in the past few years. In this paper, a topology optimization based method is applied to simultaneously determine the optimal layout of the piezoelectric energy harvesting devices and the optimal position of the mass loading. The objective function is to maximize the energy harvesting performance over a range of vibration frequencies. Pseudo excitation method (PEM) is adopted to analyze structural stationary random responses, and sensitivity analysis is then performed by using the adjoint method. Numerical examples are presented to demonstrate the validity of the proposed approach.

A level set approach for optimal design of smart energy harvesters

The proliferation of Micro-Electro-Mechanical Systems (MEMS), portable electronics and wireless sensing networks has raised the need for a new class of devices with self-powering capabilities. Vibration-based piezoelectric energy harvesters provide a very promising solution, as a result of their capability of converting mechanical energy into electrical energy through the direct piezoelectric effect. However, the identification of fast, accurate methods and rational criteria for the design of piezoelectric energy harvesting devices still poses a challenge. In this work, a level set-based topology optimization approach is proposed to synthesize mechanical energy harvesting devices for self-powered micro systems. The energy harvester design problem is reformulated as a variational problem based on the concept of topology optimization, where the optimal geometry is sought by maximizing the energy conversion efficiency of the device. To ensure computational efficiency, the shape gradient of the energy conversion efficiency is analytically derived using the material time derivative approach and the adjoint variable method. A design velocity field is then constructed using the steepest descent method, which is further integrated into level set methods. The reconciled level set (RLS) method is employed to solve multi-material shape and topology optimization problems, using the Merriman–Bence–Osher (MBO) operator. Designs with both single and multiple materials are presented, which constitute improvements with respect to existing energy harvesting designs.