Frequency tuning of piezoelectric energy harvesters by magnetic force

2012 ◽  
Vol 21 (3) ◽  
pp. 035019 ◽  
Author(s):  
Waleed Al-Ashtari ◽  
Matthias Hunstig ◽  
Tobias Hemsel ◽  
Walter Sextro
Keyword(s):  
Magnetic Force ◽  
Frequency Tuning ◽  
Energy Harvesters ◽  
Piezoelectric Energy

Modelling of Broadband Piezoelectric Energy Harvesters

2012 ◽  
Author(s):  
Shengxi Zhou ◽  
Junyi Cao ◽  
Jing Lin ◽  
Chengbin Ma
Keyword(s):  
Magnetic Force ◽  
Wide Spectrum ◽  
Magnetic Coupling ◽  
Experimental System ◽  
Polynomial Equation ◽  
Coupling Model ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Harvesting Systems ◽  
Piezoelectric Cantilevers

A nonlinear magnetic coupling model for piezoelectric energy harvesting systems is proposed in this paper. For the purpose of enhancing harvesting efficiency from wide-spectrum vibrations, a magnetic coupling structure of piezoelectric cantilevers is presented. However, the nonlinear dynamic of broadband piezoelectric energy harvesters could not be adequately described due to complex nonlinear magnetic force. Furthermore, the broken frequency can not be predicted using the designed dimensionless model. In order to solve those issues, the nonlinear magnetic force is established using polynomial equation. Based on Hamilton principle and finite element theory, a nonlinear model of the standard piezoelectric cantilever with magnetic coupling is established. Frequency sweeping experiments with various excitation are carried out. The results show that the output characteristic of the proposed model is approximate to that of experimental system under the same condition, and also their broken frequency is very close.

Nonlinear Characteristics for Rotatable Magnetically Coupling Piezoelectric Energy Harvesters

2014 ◽  
Author(s):  
Junyi Cao ◽  
Shengxi Zhou ◽  
Daniel J. Inman
Keyword(s):  
Inclination Angle ◽  
Nonlinear Dynamic ◽  
Magnetic Force ◽  
Energy Harvester ◽  
Low Frequency ◽  
High Energy ◽  
Nonlinear Characteristics ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Frequency Excitation

This paper investigates the nonlinear dynamic characteristics of a magnetically coupled piezoelectric energy harvesters under low frequency excitation, where the angle of external magnetic field is adjustable. The nonlinear dynamic equation with the identified nonlinear magnetic force is derived to describe the electromechanical interaction of variable inclination angle harvesters. The effect of excitation amplitude and frequency on dynamic behavior is proposed by using the phase trajectory and bifurcation diagram. The numerical analysis shows that a rotatable magnetically coupling energy harvesting system exhibits rich nonlinear characteristics with the change of external magnet inclination angle. The nonlinear route to and from large amplitude high energy motion can be clearly observed. It is demonstrated numerically and experimentally that lumped parameters equations with an identified polynomials for magnetic force could adequately describe the characteristics of nonlinear energy harvester. The rotating magnetically coupled energy harvester possesses the usable frequency bandwidth over a wide range of low frequency excitation by adjusting the angular orientation.

scholarly journals Load Resistance Optimization of a Broadband Bistable Piezoelectric Energy Harvester for Primary Harmonic and Subharmonic Behaviors

2021 ◽  
Vol 13 (5) ◽  
pp. 2865 ◽  
Author(s):  
Sungryong Bae ◽  
Pilkee Kim
Keyword(s):  
Energy Harvester ◽  
Load Resistance ◽  
Oscillation Period ◽  
Ambient Vibration ◽  
Ambient Vibrations ◽  
Frequency Dependency ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Optimal Load ◽  
Bistable Energy Harvester

In this study, optimization of the external load resistance of a piezoelectric bistable energy harvester was performed for primary harmonic (period-1T) and subharmonic (period-3T) interwell motions. The analytical expression of the optimal load resistance was derived, based on the spectral analyses of the interwell motions, and evaluated. The analytical results are in excellent agreement with the numerical ones. A parametric study shows that the optimal load resistance depended on the forcing frequency, but not the intensity of the ambient vibration. Additionally, it was found that the optimal resistance for the period-3T interwell motion tended to be approximately three times larger than that for the period-1T interwell motion, which means that the optimal resistance was directly affected by the oscillation frequency (or oscillation period) of the motion rather than the forcing frequency. For broadband energy harvesting applications, the subharmonic interwell motion is also useful, in addition to the primary harmonic interwell motion. In designing such piezoelectric bistable energy harvesters, the frequency dependency of the optimal load resistance should be considered properly depending on ambient vibrations.

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

Micromachines ◽  
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.

Multimodal pizza-shaped piezoelectric vibration-based energy harvesters

2021 ◽  
pp. 1045389X2110069
Author(s):  
Virgilio J Caetano ◽  
Marcelo A Savi
Keyword(s):  
Energy Harvesting ◽  
Frequency Spectrum ◽  
Optimization Procedure ◽  
Single Mode ◽  
Ambient Vibration ◽  
Vibration Source ◽  
Element Analysis ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Harvesting Systems

Energy harvesting from ambient vibration through piezoelectric devices has received a lot of attention in recent years from both academia and industry. One of the main challenges is to develop devices capable of adapting to diverse sources of environmental excitation, being able to efficiently operate over a broadband frequency spectrum. This work proposes a novel multimodal design of a piezoelectric energy harvesting system to harness energy from a wideband ambient vibration source. Circular-shaped and pizza-shaped designs are employed as candidates for the device, comparing their performance with classical beam-shaped devices. Finite element analysis is employed to model system dynamics using ANSYS Workbench. An optimization procedure is applied to the system aiming to seek a configuration that can extract energy from a broader frequency spectrum and maximize its output power. A comparative analysis with conventional energy harvesting systems is performed. Numerical simulations are carried out to investigate the harvester performances under harmonic and random excitations. Results show that the proposed multimodal harvester has potential to harness energy from broadband ambient vibration sources presenting performance advantages in comparison to conventional single-mode energy harvesters.

Performance analysis of a lever piezoelectric energy harvester for roadway applications

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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