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

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.

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Power Density Improvement of Piezoelectric Energy Harvesters via a Novel Hybridization Scheme with Electromagnetic Transduction

Micromachines ◽

10.3390/mi12070803 ◽

2021 ◽

Vol 12 (7) ◽

pp. 803

Author(s):

Zhongjie Li ◽

Chuanfu Xin ◽

Yan Peng ◽

Min Wang ◽

Jun Luo ◽

...

Keyword(s):

Power Density ◽

Output Power ◽

Energy Harvester ◽

Hybrid Energy ◽

Energy Harvesters ◽

Piezoelectric Patch ◽

Piezoelectric Energy ◽

Electromagnetic Transduction ◽

Self Powered ◽

Power Densities

A novel hybridization scheme is proposed with electromagnetic transduction to improve the power density of piezoelectric energy harvester (PEH) in this paper. Based on the basic cantilever piezoelectric energy harvester (BC-PEH) composed of a mass block, a piezoelectric patch, and a cantilever beam, we replaced the mass block by a magnet array and added a coil array to form the hybrid energy harvester. To enhance the output power of the electromagnetic energy harvester (EMEH), we utilized an alternating magnet array. Then, to compare the power density of the hybrid harvester and BC-PEH, the experiments of output power were conducted. According to the experimental results, the power densities of the hybrid harvester and BC-PEH are, respectively, 3.53 mW/cm3 and 5.14 μW/cm3 under the conditions of 18.6 Hz and 0.3 g. Therefore, the power density of the hybrid harvester is 686 times as high as that of the BC-PEH, which verified the power density improvement of PEH via a hybridization scheme with EMEH. Additionally, the hybrid harvester exhibits better performance for charging capacitors, such as charging a 2.2 mF capacitor to 8 V within 17 s. It is of great significance to further develop self-powered devices.

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Performance analysis of a lever piezoelectric energy harvester for roadway applications

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x211001445 ◽

2021 ◽

pp. 1045389X2110014

Author(s):

Guangya Ding ◽

Hongjun Luo ◽

Jun Wang ◽

Guohui Yuan

Keyword(s):

Output Power ◽

Energy Harvester ◽

Open Circuit ◽

Traffic Load ◽

Energy Harvesters ◽

Speed Sensor ◽

Piezoelectric Energy ◽

Optimal Load ◽

Self Powered ◽

Output Characteristics

A novel lever piezoelectric energy harvester (LPEH) was designed for installation in an actual roadway for energy harvesting. The model incorporates a lever module that amplifies the applied traffic load and transmits it to the piezoelectric ceramic. To observe the piezoelectric growth benefits of the optimized LPEH structure, the output characteristics and durability of two energy harvesters, the LPEH and a piezoelectric energy harvester (PEH) without a lever, were measured and compared by carrying out piezoelectric performance tests and traffic model experiments. Under the same loading condition, the open circuit voltages of the LPEH and PEH were 20.6 and 11.7 V, respectively, which represents a 76% voltage increase for the LPEH compared to the PEH. The output power of the LPEH was 21.51 mW at the optimal load, which was three times higher than that of the PEH (7.45 mW). The output power was linearly dependent on frequency and load, implying the potential application of the module as a self-powered speed sensor. When tested during 300,000 loading cycles, the LPEH still exhibited stable structural performance and durability.

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Improved Interface Circuit for Enhancing the Power Output of a Vibration-Threshold-Triggered Piezoelectric Energy Harvester

Energies ◽

10.3390/en13153830 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3830

Author(s):

Jiqiang Liu ◽

Junjie Yang ◽

Ruofeng Han ◽

Qisheng He ◽

Dacheng Xu ◽

...

Keyword(s):

Equivalent Circuit ◽

Piezoelectric Material ◽

Output Power ◽

Energy Harvester ◽

Equivalent Circuit Model ◽

Stage Structure ◽

Circuit Model ◽

Interface Circuit ◽

Piezoelectric Energy ◽

Vibration Threshold

The vibration-threshold-triggered piezoelectric energy harvester is a new type of piezoelectric energy harvester with a two-stage structure, which can generate electricity in a low frequency environment and recognize vibration intensity at the same time. In this study, a theoretical model of a vibration-threshold-triggered energy harvester was examined, and an equivalent circuit model of the energy harvester was obtained. Then, an interface circuit was proposed that can significantly improve the output power of the energy harvester. The interface circuit achieved impedance matching with the piezoelectric material to maximize the energy collected from the energy harvester. First, we calculated and analyzed the impedance characteristics of the energy harvester, based on the equivalent circuit model. It was found that because the piezoelectric material is in resonance as the energy harvester is in operation, the corresponding impedance is almost resistance. Therefore, a resistance-matching strategy was proposed. Last, we proposed an interface circuit with adjustable input impedance to achieve resistance matching. The experimental results show that the proposed interface circuit can increase the output power of the energy harvester by 48.1–55.7% over that achieved with the standard interface circuit.

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Fabrication and analytical modeling of transverse mode piezoelectric energy harvesters

MRS Proceedings ◽

10.1557/opl.2012.1012 ◽

2012 ◽

Vol 1397 ◽

Author(s):

Seon-Bae Kim ◽

Jung-Hyun Park ◽

Seung-Hyun Kim ◽

Hosang Ahn ◽

H. Clyde Wikle ◽

...

Keyword(s):

Output Power ◽

Analytical Modeling ◽

Energy Harvester ◽

Power Conversion ◽

Transverse Mode ◽

Modified Model ◽

Energy Harvesters ◽

Piezoelectric Energy ◽

Interdigital Electrodes ◽

Piezoelectric Cantilever

ABSTRACTA transverse (d33) mode piezoelectric cantilever was fabricated for energy harvesting. Various dimensions of interdigital electrodes (IDE) were deposited on a piezoelectric layer to examine the effects of electrode design on the performance of energy harvesters. Modeling was performed to calculate the output power of the devices. The estimation was based on Roundy’s analytical modeling derived for a d31 mode piezoelectric energy harvester (PEH). In order to apply the Roundy’s model to d33 mode PEH, the IDE configuration was converted to the area of top and bottom electrodes (TBE). The power conversion in d33 mode PEH was commonly estimated by the product of piezoelectric layer’s thickness and finger electrode’s length. In addition, the spacing between fingers was regarded as gap between top and bottom electrodes. However, the output power in a transverse mode PEH increases continuously with the increase of finger spacing, which does not correspond to experimental results. In this research, the dimension of IDE was converted to that of TBE using conformal mapping, and variation of power of PEH was remodeled. The modified model suggests that the maximum power in a transverse mode PEH is obtained when the finger spacing is identical with effective finger spacing. The output power then decreases when finger spacing is larger than effective finger spacing. The decrease of efficiency may result from insufficient degree of poling and increased charged defect with increasing finger spacing.

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Design and Analysis of a Magnetically Coupled Multi-Frequency Hybrid Energy Harvester

Sensors ◽

10.3390/s19143203 ◽

2019 ◽

Vol 19 (14) ◽

pp. 3203 ◽

Cited By ~ 3

Author(s):

Zhenlong Xu ◽

Hong Yang ◽

Hao Zhang ◽

Huawei Ci ◽

Maoying Zhou ◽

...

Keyword(s):

Output Power ◽

Electromechanical Coupling ◽

Energy Harvester ◽

Hybrid Energy ◽

Energy Harvesters ◽

Peak Output Power ◽

Piezoelectric Energy ◽

Operating Bandwidth ◽

Frequency Sweep Test ◽

Hybrid Energy Harvesting

The approach to improve the output power of piezoelectric energy harvester is one of the current research hotspots. In the case where some sources have two or more discrete vibration frequencies, this paper proposed three types of magnetically coupled multi-frequency hybrid energy harvesters (MHEHs) to capture vibration energy composed of two discrete frequencies. Electromechanical coupling models were established to analyze the magnetic forces, and to evaluate the power generation characteristics, which were verified by the experimental test. The optimal structure was selected through the comparison. With 2 m/s2 excitation acceleration, the optimal peak output power was 2.96 mW at 23.6 Hz and 4.76 mW at 32.8 Hz, respectively. The superiority of hybrid energy harvesting mechanism was demonstrated. The influences of initial center-to-center distances between two magnets and length of cantilever beam on output power were also studied. At last, the frequency sweep test was conducted. Both theoretical and experimental analyses indicated that the proposed MHEH produced more electric power over a larger operating bandwidth.

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Orthogonal Piezoelectric Energy Harvester for Low Frequency Applications: Modeling and Experimental Validation

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d5106.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 6268-6274

Keyword(s):

Piezoelectric Material ◽

Output Power ◽

Experimental Validation ◽

Energy Harvester ◽

Excitation Frequency ◽

Low Frequency ◽

Galvanized Steel ◽

Rotational Inertia ◽

Acceptable Error ◽

Piezoelectric Energy

The use of piezoelectric energy harvesters in low frequency applications is a classic problem due to the high elastic modulus of currently available piezoelectric materials. Furthermore, the output power is proportional to the third power of the excitation frequency. Higher excitation amplitudes or an increase in the piezoelectric material can produce a high output power. However, this is not feasible for weak environmental vibration, and using more piezoelectric material would incur a higher cost so this is not an attractive option. This article proposes an L-shaped piezoelectric energy harvester that amplifies the excitation amplitude with the aid of an extension arm. The effects of bending and rotational inertia are considered when modelling the open-circuit voltage that can be generated by the harvester. Experimental validation is carried out using zinc, aluminium and galvanized steel extension arms. The prediction model provides a good estimation of the results with acceptable error percentages for linear elastic extension arms. It is found that the proposed harvester geometry generates more output voltage for all lengths of extension arm, and the optimum lengths are different for each material. The use of a zinc extension arm generated 290 µW at 49 Hz, which is 55% greater than the power generated by a harvester without an extension arm that had a power density of 1.41 µW/mm3 .

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Modeling of V-Shaped Beam-Mass Piezoelectric Energy Harvester: Impact of the Angle Between the Beams

Volume 4: Dynamics, Control and Uncertainty, Parts A and B ◽

10.1115/imece2012-86587 ◽

2012 ◽

Cited By ~ 6

Author(s):

Wei-Jiun Su ◽

Jean W. Zu

Keyword(s):

Resonant Frequency ◽

Energy Harvester ◽

Beam Theory ◽

Energy Harvesters ◽

Piezoelectric Energy ◽

Piezoelectric Layers ◽

Cantilevered Beam ◽

Power Frequency ◽

Tip Mass ◽

Euler Bernoulli Beam

Piezoelectric material has been widely utilized in vibration-based energy harvesters (VEH). The most common configuration of piezoelectric energy harvester is a cantilevered beam with unimorph or bimorph piezoelectric layers. In this paper, a new configuration of PEH is proposed. Two beams are assembled as V shape with tip masses attached. The first beam is a cantilevered beam with tip mass while the second beam is attached to the end of the first beam with a certain angle. Piezoelectric layers are attached to both beams in unimorph configuration for power generation. The analytical solution is derived based on Euler-Bernoulli beam theory. In this analysis, the angle varies from 0 to 135 degree to see the influence of angle on voltage and power frequency response. The V-shaped VEH is proven to have the second resonant frequency relatively close to the first resonant frequency when compared with conventional cantilevered VEH. Furthermore, the angle between the two beams will influence the ratio of the second to the first resonant frequency. By choosing a suitable angle, the V-shaped structure can effectively broaden the bandwidth.

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Data-Driven Optimization of Piezoelectric Energy Harvesters via Pattern Search Algorithm

Micromachines ◽

10.3390/mi12050561 ◽

2021 ◽

Vol 12 (5) ◽

pp. 561

Author(s):

Yang Huang ◽

Zhiran Yi ◽

Guosheng Hu ◽

Bin Yang

Keyword(s):

Resonant Frequency ◽

Output Power ◽

Search Algorithm ◽

Rank Correlation ◽

Pattern Search ◽

Data Driven ◽

Optimization Strategy ◽

Energy Harvesters ◽

Spearman’S Rank Correlation ◽

Piezoelectric Energy

A data-driven optimization strategy based on a generalized pattern search (GPS) algorithm is proposed to automatically optimize piezoelectric energy harvesters (PEHs). As a direct search method, GPS can iteratively solve the derivative-free optimization problem. Taking the finite element method (FEM) as the solver and the GPS algorithm as the optimizer, the automatic interaction between the solver and optimizer ensures optimization with minimum human efforts, saving designers’ time and performing a more precise exploration in the parameter space to obtain better results. When employing it for the optimization of PEHs, the optimal length and thickness of PZT were 6.0 mm and 4.6 µm, respectively. Compared with reported high-output PEHs, this optimal structure showed an increase of 371% in output power, an improvement by 1000% in normalized power density, and a reduction of 254% in resonant frequency. Furthermore, Spearman’s rank correlation coefficient was calculated for evaluating the correlation among geometric parameters and output performance such as resonant frequency and output power, which provides a data-based perspective on the design and optimization of PEHs.

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Flexible, Piezoelectric Aluminium-doped Zinc Oxide Energy Harvesters with Printed Electrodes for Wearable Applications

International Journal of Sensors Wireless Communications and Control ◽

10.2174/2210327911666210126123257 ◽

2021 ◽

Vol 11 ◽

Author(s):

Muhammad Irsyad Suhaimi ◽

Anis Nurashikin Nordin ◽

Aliza Aini Md Ralib ◽

Lai Ming Lim ◽

Zambri Samsudin

Keyword(s):

Zinc Oxide ◽

Output Voltage ◽

Energy Harvester ◽

Wearable Sensors ◽

Low Frequency ◽

Design Parameters ◽

Axis Orientation ◽

Energy Harvesters ◽

Piezoelectric Energy ◽

Cantilever Structure

Aims: Recent advancements in sensing technology and wireless communications have accelerated the development of the Internet of Things (IoT) which promote the usage of wearable sensors. An emerging trend is to develop self-sustainable wearable devices, thus eliminating the necessity of the user to carry bulky batteries. In this work, the development of a flexible piezoelectric energy harvester that is capable of harvesting energy from low frequency vibrations is presented. The target application of this energy harvester is for usage in smart shoes. Objectives: The objectives of this research is to design, fabricate and test an energy harvester on PET substrate using Aluminum Zinc Oxide as its piezoelectric layer. Methods: The energy harvester was designed as a cantilever structure using PET/AZO/Ag layers in d33 mode which can generate large output voltages with small displacements. The electrodes were designed as an interdigitated structure in which two significant design parameters were chosen, namely the effect of gap between electrodes, g and number of interdigital electrodes (IDE) pairs, N to the output voltage and resonant frequency. Results: The sputtered AZO on PET showed c-axis orientation at 002 peak with 2 values of 34.45° which indicates piezoelectric behaviour. The silver IDE pairs were screen-printed on the AZO thin film. Functionality of the device as an energy harvester was demonstrated by testing it using a shaker. The energy harvester was capable of generating 0.867 Vrms output voltage when actuated at 49.6 Hz vibrations. Conclusion: This indicates that the AZO thin films with printed silver electrodes can be used as flexible, d33 energy harvesters.

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Performance of a Piezoelectric Bimorph Harvester with Variable Width

Journal of Mechanics ◽

10.1017/s1727719100001222 ◽

2007 ◽

Vol 23 (3) ◽

pp. 197-202 ◽

Cited By ~ 21

Author(s):

H. P. Hu ◽

Z. J. Cui ◽

J. G. Cao

Keyword(s):

Power Density ◽

Output Power ◽

Energy Harvester ◽

Design Guidelines ◽

Ambient Vibration ◽

Piezoelectric Bimorph ◽

Flexural Mode ◽

Energy Harvesters ◽

Piezoelectric Energy ◽

Further Development

AbstractThis article analyzes the performance of a piezoelectric energy harvester in the flexural mode for scavenging ambient vibration energy. The energy harvester consists of a piezoelectric bimorph plate with a variable width. A theoretical study is performed and the computational results show that the output power density increases initially, reaches a maximum, and then decreases monotonically with the increasing width, underscoring the importance for the width design of the scavenging structure. Further analysis indicates that the peak of output power density is determined by both the bimorph deformation amplitude and the efficiency in scavenging-energy. The analysis for this simplified model piezoelectric harvester provides a framework for further development on design guidelines for piezoelectric energy harvesters of optimal performance.

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