Piezoelectric Energy Research Articles

Implementation of a New Contactless Piezoelectric Wind Energy Harvester to a Wireless Weather Station

A newcontactless piezoelectric (PZT) wind energy harvester is constructed and a feasibility study on its power generationmechanism is carried out for a wireless weather station. The new harvester has a magnetic unit enabling to vibrate aPZT layer in a contactless manner. The poles of magnets are oriented in such a way that the tip of the layer is always repelled, when wind rotates the harvester shaft. Therefore the produced magnetic force exerts mechanical bucklings on the layer and this effect produces electricity. After one-year operation, it is clarified that an averaged power of 20 µW–60 µW can be obtained monthly for the feeding of the station. These results prove that 5 %–18 % of the consumed power of wireless station can be generated by the harvester depending on the wind regime in the region. DOI: http://dx.doi.org/10.5755/j01.eee.20.10.8871

Establishment of the evaluation standard and the analysis technique for the tip mass method in piezoelectric energy - harvesting systems

Two models were developed a pre-stress model and a no-pre-stress model for considering the effects of a tip mass with and without pre-stress induced by gravity, respectively. Three tip masses-6, 18, and 30 g-were used in experiments, and four cases were considered: the above three tip masses and a 0 g case, corresponding to no tip mass. Two prominent effects of the tip mass were theoretically predicted and experimentally verified. We established an evaluation standard and an analysis technique for efficiently analyzing these two effects of the tip mass on the output power of a piezoelectric energy-harvesting system. For both models, a higher output power was obtained in a system with a tip mass than in a system without a tip mass. Results of the experiments and of a critical voltage analysis demonstrated that the developed tip mass method successfully augmented the output power of the system.

Experimental study and finite element analysis for piezoelectric impact energy harvesting using a bent metal beam

Linear uniform beams have been extensively investigated as a typical piezoelectric vibration energy harvesting mechanism in both conventional cantilever-beam-based harvester and a novel internal impact type energy harvester, the latter is of broad bandwidth and frequency up-converting capability and therefore quite suitable to low frequency ambient vibrations. To sufficiently utilize the space of the existing internal impact type energy harvester, a bent metal beam with distributed piezoelectric patches is proposed and investigated as the vibration energy harvesting module. A prototype harvester has been built and performances including the voltage and output power have been tested by experiments and analyzed by the finite element analysis. Both experiment and finite element analysis show that the proposed structure can effectively harvest vibration energy. And the optimal position for energy harvesting in this structure is also found. This work indicates that the frame of the existing internal impact type energy harvester may be used to harvest vibration energy, if it is bonded with distributed piezoelectric patches, which gives a way to increase its power density.

Coupling effect analysis for hybrid piezoelectric and electromagnetic energy harvesting from random vibrations

Through establishing the electroelastic model of hybrid piezoelectric(PE) and electromagnetic(EM) energy harvesting from random vibrations, normalized expressions of mean amplitude, voltage, current, power and their spectral density (SD) are derived, and effects of electromechanical coupling strength on harvester’s performances are studied by numerical calculation and experimental test. It is found that the stronger coupling effect, the smaller amplitude and working space required, and the bigger mean voltage, current and power output until up to their maximums. Furthermore, variation extent of mean voltage, current and power with the PE and EM load increasing varies with the coupling strength. Besides, coupling strength changes the SD distributing in frequency domain. In the weak coupling, maximal SD of voltage, current and power are at the natural frequency of harvester. However, with the coupling effect strengthening, the frequency corresponding to peak spectral density is bigger than the natural frequency, and the 3dB bandwidth of harvester is much larger accordingly; moreover, the bandwidth decreases with EM load increasing while it rises firstly and fall later with PE load increasing, which reaches the maximum at the optimal load. The analysis results can provide certain criteria for hybrid piezoelectric-electromagnetic energy harvester design.

Modeling and Analysis of Micro Piezoelectric Vibration Energy Harvesters Based on the Theory of Strain Gradient

The dynamic model of micro piezoelectric vibration energy harvesters is established using the theory of strain gradient, the model reflects the effect of the scale of the micro system.The expression of the output voltage is gotten through solving the model, and then the parameters are simulated, the results of simulation accord with the experimental data

A review of piezoelectric vibration energy harvesting techniques

In this paper, recent published techniques for vibration energy harvesting with piezoelectric materials have been summarized. The various techniques described are classified in terms of linear and nonlinear vibration energy harvesters, harvesting electrical circuits, large scale vibration energy harvesting concept. The focus is on linear vibration energy harvester but with multiple resonant mode models. The paper concluded with an overview of vibration energy harvesting techniques that aim to maximize the extracted power and the future utilization of the vibration energy harvester.

Piezoelectric Vibration Energy Harvesting Device Combined with Damper

Piezoelectricity is a type of material that enables mechanical energy and electrical energy to be interchangeable, which can be divided into positive piezoelectric effect and inverse piezoelectric effect. The positive piezoelectric effect is that the electric dipole moment of material generates changes when the piezoelectric material is subjected to pressure, resulting in electrical energy. Conversely, the inverse piezoelectric effect is the process of electrical energy converted into mechanical energy.

蒲公英状压电振动能量收集装置宽频带设计

The wide-band design of a dandelion-shape piezoelectric vibration energy harvester was investigated to process the variety of the ambient vibration energy sources.A analysis model of resonant frequency for dandelion-shape piezoelectric vibration energy harvester was established.The theoretical results show that the frequency band of resonant frequency of the energy harvester can not be increased randomly.To verify the theoretical analysis,a frequency response experiment was performed,and the results obtained from the theoretical model indicate that theoretical analysis isbasically in agreement with the experimental results.Finally,the experiments were performed to measure the generating capacity of the dandelion-shape piezoelectric vibration energy harvester.The research results show that after a wide-band design for the dandelion-shape piezoelectric vibration energy harvester,it has higher output power in the range of 20Hz-34Hz and the maximal output power is around 2.3mW.The results demonstrate that the proposed piezoelectric vibration energy harvester can effectively increase the band of resonant frequency through the wide-band design and is easy to match the ambient vibration energy sources to get more vibration energies.

Enhance limit cycle oscillation in a wind flow energy harvester system with fractional order derivatives

Advances in material science and mathematics in conjunction with technological needs have triggered the use of material and electric components with fractional order physical properties. This paper considers the mathematical model of a piezoelectric wind flow energy harvester system for which the capacitance of the piezoelectric material has fractional order current-voltage characteristics. Additionally the mechanical element is assumed to have fractional order damping. The analysis is focused on the effects of order of derivatives on the appearance and characteristics of limit circle oscillations (LCO). It is obtained that, the order of derivatives to enhance the amplitude of LCO and lower the threshold condition leading to LCO. The domains of efficiency of the system are illustrated in various parameters spaces.

A Bulk Micromachined Lead Zinconate Titanate Cantilever Energy Harvester with Inter-Digital IrO<SUB><I>x</I></SUB> Electrodes

A piezoelectric vibration energy harvester with inter-digital IrO(x) electrode was developed by using silicon bulk micromachining technology. Most PZT cantilever based energy harvesters have utilized platinum electrode material. However, the PZT fatigue characteristics and adhesion/delamination problems caused by the platinum electrode might be serious problem in reliability of energy harvester. To address these problems, the iridium oxide was newly applied. The proposed energy harvester was comprised of bulk micromachined silicon cantilever with 800 x 1000 x 20 microm3, which having a silicon supporting membrane, sol-gel-spin coated Pb(Zr52, Ti48)O3 thin film, and sputtered inter-digitally shaped IrO(x) electrodes, and silicon inertial mass with 1000 x 1000 x 500 microm3 to adjust its resonant frequency. The fabricated energy harvester generated 1 microW of electrical power to 470 komega of load resistance and 1.4 V(peak-to-peak) from a vibration of 0.4 g at 1.475 kHz. The corresponding power density was 6.25 mW x cm(-3) x g(-2). As expected, its electrical failure was significantly improved.

Analysis of Output Performance for Piezoelectric Double Mode Energy Harvester

The output performance of piezoelectric double mode energy harvester is studied, which is provided with a dynamic magnifier consisting of a spring-mass system placed between the piezoelectric element and the moving base. The theory governing the operation of the energy harvester with dynamic magnifier is developed using the Lagrangian dynamic approach, Numerical examples are presented to illustrate the output performance of the energy harvester in comparison with the conventional energy harvester, the results show that with proper selection of the design parameters of the magnifier, the harvested power can be dramatically enhanced and the effective bandwidth of the harvester can be improved.

Modal electromechanical optimization of cantilevered piezoelectric vibration energy harvesters by geometric variation

The design studies of cantilevered piezoelectric vibration energy harvesters have been focused on the optimization of the power output of rectangular cantilevered beam vibration energy harvesters. However, without clarifying the influences of the modal electromechanical coupling and mechanical behaviour clearly, the power outputs cannot be adequately optimized. In this article, a distributed parameter electromechanical model is used to predict the power output with resistive loads, and the parameters are derived using the finite element method. First, a parametric study is presented to investigate the effects of the two factors on the volumetric power of cantilevered vibration energy harvesters. Then, an optimization strategy is implemented to investigate the modal electromechanical coupling coefficient and mass ratio separately using geometric parameter study. Mass ratio represents the influences of modal mechanical behaviour on the power density directly. The findings indicate that the convergent and divergent tapered cantilevered and rectangular cantilevered beam designs with partial coverage of piezoelectric layer are able to generate higher electromechanical coupling coefficient than conventional rectangular cantilevered designs with full coverage. Besides, using convergent tapered cantilevered designs can actually decrease the power density significantly. Both using divergent tapered cantilevered structures and attaching reasonable extra masses with varied locations on vibration energy harvesters can generate larger power density.

Analysis of Variable Section Piezoelectric Harvester

This paper first presents an analytical model for investigating the vibration performance of a thin curved laminated piezoelectric beam with variable curvatures and transverse sections. This kind of beam is widely used for the MEMS piezoelectric vibration energy harvester. The curved thin beam theory with bisymmetric section, here rectangular section used, is employed to explore the bending and twisting coupling vibration characteristics. In order to study the vibration properties with concentrated load, the effects of the tip proof mass isnt used. The paper also shows that the adoption of ANSYS software to carry out the MEMS piezoelectric vibration energy harvesters numerical simulation can improve the efficiency of the harvester designing and manufacturing consumedly. The results showed that the maximum voltage at the resonant point was increasing while the initial curvature radius increasing. On the other hand, the voltage difference of the inner edge and the outer edge was very small because the matrix layer was PDMS with very small stiffness and density.

Experimental Study of Resonant Frequency Tunable Piezoelectric Energy Harvester

Abstract. To improve energy harvesting performance, a resonance frequency tunable piezoelectric (PZT) energy harvester for vibrating applications was presented and investigated experimentally. A piezoelectric vibrational energy harvester (PVEH) consisted of a piezo-cantilever with a permanent magnet at its free-end and another excitation magnet fixed on vibration structure. The two magnets are placed with the same magnetic poles facing each other to produce repulsive force. The cantilever has dimensions of 70x10x0.6mm3, clamped 10mm, and two magnets sized ø10x4mm3. The testing results show that the magnetic force, denoted by the initial separated distance between the magnetic dipoles (SDMD), exerts great influence on the generated performance. With the SDMD increasing from 15mm to 40mm, the generated voltage rises from 24.4V to 40V, and the resonant frequency increases from 33.75Hz to 38.75Hz.

Power enhancing by reversing mode sequence in tuned mass-spring unit attached vibration energy harvester

We propose a vibration energy harvester consisting of an auxiliary frequency-tuned mass unit and a piezoelectric vibration energy harvesting unit for enhancing output power. The proposed integrated system is so configured that its out-of-phase mode can appear at the lowest eigenfrequency unlike in the conventional system using a tuned unit. Such an arrangement makes the resulting system distinctive: enhanced output power at or near the target operating frequency and very little eigenfrequency separation, not observed in conventional eigenfrequency-tuned vibration energy harvesters. The power enhancement of the proposed system is theoretically examined with and without tip mass normalization or footprint area normalization.

A Magnet-Coupled Piezoelectric Vibration Energy Harvester

To improve energy harvesting performance, a magnet-coupled piezoelectric vibration energy harvester (MCPEH) for low-level and low-frequency vibration was presented and investigated experimentally. The MCPEH consisted mainly of a piezo-cantilever with a permanent magnet at its free-end and another excitation magnet fixed on vibration structure. The magnets are used to produce magnetic attractive force to enhance energy generation. A MCPEH was fabricated with a piezo-cantilever measured 60x10x0.5mm3 and two magnets sized ø12x3mm3. The testing results show that the magnetic force, denoted by the initial separated distance between the magnetic dipoles (SDMD), exerts great influence on all of the generated voltage, optimal frequency, and effective bandwidth. With the SDMD reducing from 40mm to 15mm, the optimal frequency decrease from 32.75Hz to 30.5Hz, the effective bandwidth for the MCPEH to generated voltage of 15V rises from 2.5Hz to 7.5Hz, and the generated voltage rises from 30.4V to 44.4V.

Optimal design of piezoelectric materials and devices for energy harvesting

Piezoelectric vibration energy harvesters (PVEHs) have received considerable attention as an enabling technology for self-powered wireless sensor networks. However, the biggest challenge with PVEHs has been their insufficient power generation for practical applications, which necessitates creative and disruptive materials and structure design on various scales. In this work, a model-based design study is performed that includes structural, materials, and device-level power optimizations of PVEHs. The optimization results help in understanding the behavior of the device performance, such as voltage and power, when the devices are optimized under various operating conditions, including input operating frequencies and mechanical damping. Furthermore, the optimization provides both an optimal device design scheme for power improvement and a better understanding of the correlation between the material property and the energy-harvesting output performance.

PZT / MWNTs / EP Piezoelectric Damping Composites Conductivity and Dynamic Mechanical Analysis

According to piezoelectricity and electrical conductivity theory, the ternary system piezoelectric damping composites containing piezoelectric ceramic powder (PZT) / multi-walled carbon nanotubes (MWNTs) / epoxy resin (EP) were developed. Through the conductive and mechanical performance test of composites, the paper showed the piezoelectric damping energy dissipation mechanism of polymer composites. Results indicated that: the loss factor of materials would increase with the increasing of PZT content. When the content of PZT exceeded a certain value, tanδ would increase dramatically. When the content of MWNTs is 2%, tanδ reached a high value. This meant composites played the role of shock absorbing by conducting electricity from piezoelectric effect of PZT to external circuit.

A Piezoelectric Wind Energy Harvester for Wireless Sensor Networks

This paper proposes a miniaturized piezoelectric wind energy harvester to power wireless sensor networks. The harvester consists of a lead zirconate titanate (PZT) cantilever beam and a flexible plate. The flexible plate triggers flutter motion at a low wind speed, causing the rigid PZT cantilever beam to vibrate with large amplitude. Two styles of the harvesters were designed and tested in a wind tunnel. The critical wind speed, the output voltage and the power of the wind energy harvesters were measured. Maximum power of 0.199 and 0.666 mW were obtained at the wind speeds of 10 and 15 m/s, respectively. As an alternative power source, the harvesters have great potential to replace the battery or extend the lifespan of the wireless sensor networks.

J161013 ステンレス基板上圧電薄膜を用いたMEMSエナジーハーベスター([J161-01]マイクロナノメカトロニクス(1))

J161013 ステンレス基板上圧電薄膜を用いたMEMSエナジーハーベスター([J161-01]マイクロナノメカトロニクス(1))