A twisting vibration based energy harvester for ultra-low frequency excitations

2020 ◽  
Vol 64 (1-4) ◽  
pp. 693-700
Author(s):  
Kangqi Fan ◽  
Hengheng Qu ◽  
Meiling Cai
Keyword(s):  
Outer Surface ◽  
Potential Application ◽  
Energy Harvester ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Excitation Amplitude ◽  
Human Hand ◽  
Initial Angle ◽  
Surrounding Environment ◽  
Vibration Of A String

Ultra-low frequency mechanical excitations are omnipresent in our surrounding environment, but the efficient exploitation of them is generally difficult because they normally drive the widely reported cantilevered harvesters to work under non-resonant conditions. Although the frequency up-conversion strategy has been proposed to mitigate this issue, it usually leads to complicated structures. This paper reports a novel energy harvesting approach based on the twisting vibration of a string-driven rotor. To examine the feasibility of this approach, an electromagnetic energy harvester is designed, which is composed of a lid, a rotor with embedded magnets, a pendant, and a tube with pick-up coils attached to the outer surface. The rotor is suspended between the lid and the pendant through a piece of string, and then actuated by the ambient excitations through the string. Under the excitations produced by a crank-slider mechanism, the designed harvester can generate useful electric outputs that are proportional to the excitation amplitude, the initial angle between the pendant and lid, and the excitation frequency. Moreover, the harvester can also provide 0.034 mW power when it is periodically pulled by the human hand at approximately 1 Hz. This study demonstrates the potential application of the string-driven rotor in collecting energy from ultra-low frequency excitations.

Modeling and Experimental Validations of a Piezoelectric Energy Harvester Under Combined Galloping and Base Excitations

2014 ◽  
Author(s):  
Amin Bibo ◽  
Abdessattar Abdelkefi ◽  
Mohammed F. Daqaq
Keyword(s):  
Bluff Body ◽  
Energy Harvester ◽  
Constitutive Relations ◽  
Excitation Frequency ◽  
Primary Resonance ◽  
Beam Theory ◽  
Excitation Amplitude ◽  
The Body ◽  
Base Excitation ◽  
Piezoelectric Energy

This paper develops an experimentally validated model of a piezoelectric energy harvester under combined aeroelastic-galloping and base excitations. To that end, an energy harvester consisting of a thin piezoelectric cantilever beam subjected to vibratory base excitation is considered. To permit galloping excitation, a bluff body is rigidly attached at the free end such that a net aerodynamic lift is generated as the incoming airflow separates on both sides of the body giving rise to limit cycle oscillations when the flow velocity exceeds a critical value. A nonlinear electromechanical distributed-parameter model of the harvester under the combined excitation is derived using the energy approach and by adopting the nonlinear Euler-Bernoulli beam theory, linear constitutive relations for the piezoelectric transduction, and the quasi-steady assumption for the aerodynamic loading. The partial differential equations of the system are discretized and a reduced-order-model is obtained. The mathematical model is validated by conducting a series of experiments with different loading conditions represented by wind speed, base excitation amplitude, and excitation frequency around the primary resonance.

An Electromagnetic Frequency Increased Vibration Energy Harvester

2011 ◽  
Vol 403-408 ◽  
pp. 4231-4234 ◽  
Author(s):  
Khalid Ashraf ◽  
Mohd Haris Md Khir ◽  
John Ojur Dennis
Keyword(s):  
Permanent Magnets ◽  
Energy Harvester ◽  
Proof Mass ◽  
Excitation Frequency ◽  
Average Power ◽  
Low Frequency ◽  
High Frequency Oscillation ◽  
Vibration Energy ◽  
Frequency Oscillation ◽  
Vibration Energy Harvester

This paper presents an impact-based frequency increased electromagnetic vibration energy harvester to scavenge energy in a low frequency environment. To realize the novel impact based frequency up-conversion mechanism, a coil has been elastically anchored with a platform on which four permanent magnets are arranged in such a way that a strong closed magnetic flux path, linking the coil, is formed. The proposed scavenger has two dynamics of motion. The first phase is a low frequency oscillation to absorb energy from ambient vibration during which both the coil and magnet act as proof mass and move collectively. The increased proof mass ensures maximization of absorbed energy. After crossing a certain clearance, the platform containing magnetic setup rigidly and supporting the coil elastically, collides with a rigid stopper and bounces back. As a result of this mechanical impact a high frequency oscillation is setup in the coil relative to the magnets during which energy is transferred to electrical domain by electromagnetic induction. A macro-prototype has been build to prove the proposed concept. Initial test results show that the proposed harvester generates a peak voltage of 1 volt across a load of 220 Ω at an excitation frequency of 5 Hz which corresponds to a peak power of 4.5 mW and average power of 660 µW.

Design and Experimental Verification of Torsion-Bending Low-Frequency Piezoelectric Energy Harvesters

2016 ◽  
Author(s):  
Hichem Abdelmoula ◽  
Nathan Sharpes ◽  
Hyeon Lee ◽  
Abdessattar Abdelkefi ◽  
Shashank Priya
Keyword(s):  
System Analysis ◽  
Energy Harvester ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Load Resistance ◽  
Mode Shapes ◽  
Low Frequencies ◽  
Piezoelectric Energy ◽  
The Masses ◽  
Tip Mass

We design and experimentally validate a zigzag piezoelectric energy harvester that can generate energy at low frequencies and which can be used to operate low-power consumption electronic devices. The harvester is composed of metal and piezoelectric layers and is used to harvest energy through direct excitations. A computational model is developed using Abaqus to determine the exact mode shapes and coupled frequencies of the considered energy harvester in order to design a broadband torsion-bending mechanical system. Analysis is then performed to determine the optimal load resistance. The computational results are compared and validated with the experimental measurements. More detailed analysis is then carried out to investigate the effects of the masses on the bending and torsion natural frequencies of the harvester and generated power levels. The results show that due to the coupling between the bending and torsion modes of the zigzag structure, highest levels of the harvested power are obtained when the excitation frequency matches the coupled frequency of torsion type for three different values of the tip mass.

Broadband and Low Frequency Vibration-Based Energy Harvesting Improvement Through Magnetically Induced Frequency Up-Conversion

2010 ◽  
Author(s):  
Adam M. Wickenheiser
Keyword(s):  
Energy Harvester ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Beam Theory ◽  
Magnetic Interaction ◽  
Large Mass ◽  
Stochastic Simulations ◽  
Base Excitation ◽  
Low Frequency Vibration ◽  
Compact Design

In order to extract as much energy as possible from ambient vibrations, many vibration-based energy harvesters (VEHs) are designed to resonate at a specific base excitation frequency. Unfortunately, many vibration energy sources are low frequency (0.5 Hz–100 Hz), intermittent, and broadband. Thus, resonant VEHs would not be excited continuously and would require a large mass or size to tune to such a low frequency. This work presents the modeling, analysis, and experimental application of a nonlinear, magnetically excited energy harvester that exhibits efficient broadband, frequency-independent performance. This design utilizes a passive auxiliary structure that remains stationary relative to the base motion of the VEH. This device is especially effective for driving frequencies well below its fundamental frequency, thus enabling a more compact design compared to traditional resonant topologies. A mechanical model based on Euler-Bernoulli beam theory is coupled to a linear circuit and a model of the nonlinear, magnetic interaction to produce a distributed parameter magneto-electromechanical system. The results of both harmonic and broadband, stochastic simulations demonstrate multiple-order-of-magnitude power harvesting performance improvement at low driving frequencies and an insensitivity to time-varying base excitation frequency content. Furthermore, the proposed system is shown to enable more practical designs than a resonant energy harvester for the specific example of harvesting energy from walking motion.

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

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 .

Structure-Excitation Modal Decoupling by Modification of the Involved Acoustic Modes of the Sound Insulating Enclosure

2001 ◽  
Author(s):  
Christos I. Papadopoulos ◽  
Ioannis T. Georgiou
Keyword(s):  
Feasible Solution ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Excitation Amplitude ◽  
Acoustic Response ◽  
Noise Sources ◽  
Acoustic Modes ◽  
Band Noise ◽  
Simultaneous Control ◽  
Narrow Frequency Band

Abstract Several noise sources such as machinery with rotating or reciprocating parts routinely produce high levels of noise in narrow frequency ranges lying in the neighbourhood of the rotating or reciprocating frequency and their harmonics. When enclosures are used to isolate such noise sources, peak response might be observed at these frequency ranges due both to increased excitation amplitude and resonating phenomena caused by the interaction of the excitation with the acoustic modes of the enclosure. Especially in the low frequency range and for low or intermediate wall absorption, the acoustic response of the enclosure is modal and these peak responses can be intense. This paper proposes a methodology to minimize the effect of narrow-frequency-band noise by redistribution of the acoustic modes of the insulating enclosure. This can be achieved by shifting the enclosure acoustic modes away from the excitation frequency so as to make superimposed resonating phenomena less intense. For that, several variable geometric modifications of the enclosure walls are introduced. The magnitude of those modifications that will lead to sparse mode distribution in the neighbourhood of the excitation frequency is estimated by means of a combined finite element-optimisation method. The above methodology is applied to an orthogonal enclosure and two different narrow-band loads in the neighbourhood of 90 and 120 Hz are studied. It is shown that, for each frequency load, a feasible set of geometric modifications can be found so as for the neighbouring modes to be shifted and, consecutively, for resonating effects to be made less intense. Furthermore it is shown that feasible solution to the problem of simultaneous control of noise having two or more intense excitation frequencies is also attainable.

Uncertainty Analysis of Energy Harvesting Systems

2014 ◽  
Author(s):  
Reza Madankan ◽  
M. Amin Karami ◽  
Puneet Singla
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Design Parameters ◽  
Unscented Transformation ◽  
Energy Harvesters ◽  
Harvesting Systems

This paper presents the relation between uncertainty in the excitation and parameters of vibrational energy harvesting systems and their power output. Nonlinear vibrational energy harvesters are very sensitive to the frequency of the base excitation. If the excitation frequency does not match with the resonance frequency of the energy harvester, the power output significantly deteriorates. The mismatch can be due to the inherent changes of the ambient oscillations. The fabrication errors or gradual changes of material properties also result in the mismatch. This paper quantitatively shows the probability density function for the power as a function of the probability densities of the excitation frequency, excitation amplitude, initial deflection of the energy harvester, and design parameters. Recently developed the conjugated unscented transformation methodology is used in conjunction with the principle of maximum entropy to compute the probability distribution for the base response and power. The computed nonlinear density functions are validated against Monte Carlo simulations.

Broadband Low-Frequency Vibration Energy Harvester with a Rolling Mass

2013 ◽  
Vol 404 ◽  
pp. 635-639 ◽  
Author(s):  
Xue Feng He ◽  
You Zhu ◽  
Yao Qing Cheng ◽  
Jun Gao
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Maximum Output Power ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Vibration Energy ◽  
Maximum Output ◽  
Vibration Energy Harvester ◽  
Low Frequency Vibration ◽  
Half Power

Richness of broadband low-frequency vibration energy in environemnts makes it significant to develop broadband low-frequency vibration energy harvesters. A vibration energy harvester composed of two symmetrical cantilevered piezoelectric bimorphs and a rolling mass in a guiding channel was proposed. A prototype of the vibration energy harvester with a rolling mass was assembled and tested. The base excitation caused the rolling mass to impact with two cantilevered bimorphs repeatedly and the impacts cause the bimorphs to vibrate dramatically. Experimental results show that maximum output power and corresponding excitation frequency increased with the amplitude of base acceleration. For the prototype, the maximum output power of a piezoelectric bimorph on a resistor with the resistance of 100 kΩ was 602 μW under base acceleration with the amplitude of 1.5 g and frequency of 37 Hz, and the half power bandwidth was about 13.5% or 5 Hz.

scholarly journals Full-Scale Simulations of Magnetorheological Damper for Implementation of Semi-Actively Structural Control

2018 ◽  
Vol 35 (4) ◽  
pp. 549-562 ◽  
Author(s):  
Y. B. Peng ◽  
Z. K. Zhang ◽  
J. G. Yang ◽  
L. H. Wang
Keyword(s):  
Structural Control ◽  
Low Cost ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Mr Damper ◽  
Excitation Amplitude ◽  
Full Scale ◽  
Magnetorheological Damper ◽  
Input Current ◽  
Two Dimensional

ABSTRACTFull-scale simulations of a (Magnetorheological) MR damper are carried out for revealing its hysteretic behaviors associated with implementation of semi-active control using the routine of computational fluid dynamics. By virtue of the structural symmetry of the MR damper, a two-dimensional configuration for finite element simulation is built up. Herschel-Bulkley model is employed to represent the property of the MR fluid, of which the control parameters and their relevances to the input current are addressed. Typical cases involving sinusoidal and irregular displacements, steady and transient currents loaded upon the MR damper are investigated. Numerical investigations reveal that the damper force has a positive correlation with input current, excitation amplitude and excitation frequency. The full-scale simulation is proved to exhibit a sound accuracy through the validation of experimental data. It provides a logical manner revealing the true performance of MR dampers under desirable operating modes in practice, and can be readily integrated with the gain design of the associated semi-actively controlled structure. This progress bypasses the technical challenge inherent in the traditional tests with low-frequency cyclic loadings due to the limitation of experimental setup. Besides, comparative study between two-dimensional and three-dimensional configuration simulations of the MR damper shows that former has a better applicability, which can be carried out on a low-cost platform.

scholarly journals Comprehensive Review on Effective Strategies and Key Factors for High Performance Piezoelectric Energy Harvester at Low Frequency

2019 ◽  
Vol 16 (4) ◽  
pp. 7181-7210 ◽  
Author(s):  
N. H. H. A. Talib ◽  
H. Salleh ◽  
B. D. Youn ◽  
M. S. M. Resali
Keyword(s):  
Power Density ◽  
Output Power ◽  
High Performance ◽  
Energy Harvester ◽  
Material Selection ◽  
Rapid Development ◽  
Low Frequency ◽  
Excitation Amplitude ◽  
Piezoelectric Energy ◽  
Limited Application

In the past decade, there has been rapid development in piezoelectric energy harvester due to its limited application and low output power. This paper critically reviews the strategies implemented to improve the power density for low-frequency applications. These strategies include piezoelectric material selection as well as optimisations of shape, size and structure. The review also focuses on the recent advances in multi-modal, nonlinear and multi-directional energy harvesting. Based on the comprehensive summary of the normalised power density at 1g acceleration, it was found that most works fell in the second quadrant of low frequency and high power density. The maximum value was around 1mW/mm3 /g. Adding an extension of beam or spring to the conventional piezoelectric beam could enhance the normalised power density dramatically. Additionally, the multi-modal energy harvester exhibits broader bandwidth when its multiple resonance peaks get closer. The findings indicate that the anticipated performance of a piezoelectric harvester can be attained by achieving the trade-off between output power and bandwidth. To achieve high performance at low frequency, the following factors are essential: excellent material characteristics optimised geometry for high strain energy density, excellent flexibility, high excitation amplitude and broad bandwidth. 

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