Investigation of Power Harvesting via Parametric Excitations

2008 ◽  
Vol 20 (5) ◽  
pp. 545-557 ◽  
Author(s):  
Mohammed F. Daqaq ◽  
Christopher Stabler ◽  
Yousef Qaroush ◽  
Thiago Seuaciuc-Osório
Keyword(s):  
Output Power ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Multiple Scales ◽  
Broad Band ◽  
Parametric Instability ◽  
Load Resistance ◽  
Resistive Load ◽  
Parametrically Excited ◽  
Critical Excitation

This article presents an analytical and experimental investigation of energy harvesting via parametrically excited cantilever beams. To that end, we consider a lumped-parameter non-linear model that describes the first-mode dynamics of a parametrically excited cantilever-type harvester. The model accounts for the beam's geometric and inertia non-linearities as well as non-linearities representing air drag. Using the method of multiple scales, we obtain approximate analytical expressions describing the beam response, voltage drop across a purely resistive load, and output power in the vicinity of the first principle parametric resonance. Using these expressions, we study the effect of the electromechanical coupling and load resistance on the output power. We show that these parameters play an imperative role in determining the magnitude of the output power and characterizing the broad-band properties of the harvester. Specifically, we show that the region of parametric instability wherein energy can be harvested shrinks as the coupling coefficient increases. Furthermore, we show that there exists a coupling coefficient beyond which the peak power decreases. We also demonstrate that there is a critical excitation level below which no energy can be harvested. The amplitude of this critical excitation increases with the coupling coefficient and is maximized for a given load resistance. Theoretical findings that were compared to experimental results show good agreement and reflect the general trends.

scholarly journals Parametric Amplification in the Context of Vibratory Energy Harvesting

2011 ◽  
Author(s):  
R. Donovan Bode ◽  
Mohammed F. Daqaq
Keyword(s):  
Output Power ◽  
Tilt Angle ◽  
Multiple Scales ◽  
Energy Content ◽  
Damping Ratio ◽  
Harmonic Component ◽  
Parametric Amplification ◽  
Resistive Load ◽  
Fundamental Component ◽  
Mechanical Damping

In this manuscript, we propose a technique to harvest energy from excitation sources that possess two frequency components: a fundamental component with large energy content, and a super-harmonic component with smaller energy content at twice the fundamental component. Excitations of this nature are common in the environment due to inherent nonlinearities in the dynamics of the excitation source. Normally, two separate energy harvesters are needed to extract the energy at each frequency; however, this paper discusses a single cantilevered piezoelectric vibratory energy harvester (VEH) that exploits the parametric amplification phenomenon to scavenge energy from both frequencies by varying the tilt angle between the axis of the harvester and the direction of the excitation. To investigate the efficacy of the proposed concept, the equations governing the electromechanical dynamics of the harvester are derived. The resulting partial differential equations and associated boundary conditions are then reduced to a single-mode Galerkin based reduced-order model. Analytical expressions for the steady-state output power across a purely resistive load are obtained using the method of multiple scales. Results indicate that percentage improvement in the output power depends on the excitation’s parameters, the tilt angle, and the mechanical damping ratio. It is observed that there is an optimal tilt angle at which the flow of energy from the environment to the electric load is maximized. Furthermore, when the mechanical damping ratio is small, significant enhancement in the output power is attainable even when the magnitude of the super-harmonic is very small when compared to the fundamental component. Such findings reveal that, under certain conditions, parametric amplification can be utilized to enhance the output power of a VEH especially for micro-scale applications where the damping ratio can be easily controlled. Experimental results are presented to validate the theoretical concepts.

scholarly journals Enhancing Wind Energy Harvesting Using Passive Turbulence Control Devices

2019 ◽  
Vol 9 (5) ◽  
pp. 998 ◽  
Author(s):  
Junlei Wang ◽  
Guoping Li ◽  
Shengxi Zhou ◽  
Grzegorz Litak
Keyword(s):  
Wind Speed ◽  
Energy Harvesting ◽  
Output Power ◽  
Electromechanical Coupling ◽  
Load Resistance ◽  
Turbulence Control ◽  
Critical Wind Speed ◽  
Piezoelectric Energy ◽  
Optimal Load ◽  
Passive Turbulence Control

Aiming to predict the performance of galloping piezoelectric energy harvesters, a theoretical model is established and verified by experiments. The relative error between the model and experimental results is 5.3%. In addition, the present model is used to study the AC output characteristics of the piezoelectric energy harvesting system under passive turbulence control (PTC), and the influence of load resistance on the critical wind speed, displacement, and output power under both strong and weak coupling are analyzed from the perspective of electromechanical coupling strength, respectively. The results show that the critical wind speed initially increases and then decreases with increasing load resistance. For weak and critical coupling cases, the output power firstly increases and then decreases with the increase of the load resistance, and reaches the maximum value at the optimal load. For the weak, critical, and strong coupling cases, the critical optimal load is 1.1 MΩ, 1.1 MΩ, and 3.0 MΩ, respectively. Overall, the response mechanism of the presented harvester is revealed.

scholarly journals Analytical Modeling of a Doubly Clamped Flexible Piezoelectric Energy Harvester with Axial Excitation and Its Experimental Characterization

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3861
Author(s):  
Jie Mei ◽  
Qiong Fan ◽  
Lijie Li ◽  
Dingfang Chen ◽  
Lin Xu ◽  
...  
Keyword(s):  
Output Power ◽  
Power Output ◽  
Output Voltage ◽  
Energy Harvester ◽  
Load Resistance ◽  
Engineering Practice ◽  
Maximum Output ◽  
Widespread Application ◽  
Piezoelectric Energy ◽  
Axial Excitation

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.

Sb5+ Modified Phase Transition in (Li, Na, K)(Nb1-xSbx)O3 Piezoelectric Ceramics

2016 ◽  
Vol 848 ◽  
pp. 339-343
Author(s):  
Xiao Kun Zhao ◽  
Bo Ping Zhang ◽  
Lei Zhao ◽  
Li Feng Zhu
Keyword(s):  
Phase Transition ◽  
Phase Boundary ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Electromechanical Coupling Coefficient ◽  
Second Phase ◽  
Phase Transition Temperatures ◽  
Two Peaks ◽  
Planar Mode

The modified behavior of the phase transition temperatures (TO-T and/or TC) between orthorhombic (O), tetragonal (T) and cubic (C) that caused by doping Sb5+ in (Li0.052Na0.493K0.455)(Nb1-xSbx)O3 (LNKNSx) ceramics was reported in the present investigation. The results show that differing from the insensitive TO-T to the Sb5+ content, TC splits into two peaks TCI and TCII when doping Sb5+. The decreased TCI by raising x may be ascribed to the Sb-rich grains and the settled TCII round 480 °C resulting from the Sb-lack ones. The enhanced piezoelectric coefficient d33 value of 263 pC/N and planar mode electromechanical coupling coefficient kp value of 42.5% at x=0.052 can be attributed to the polymorphic phase boundary (PPB) behavior with an appropriate ratio between T and O phases without any second phase.

scholarly journals Combined piezoelectric and flexoelectric effects in resonant dynamics of nanocantilevers

2018 ◽  
Vol 29 (20) ◽  
pp. 3949-3959 ◽  
Author(s):  
Adriane G Moura ◽  
Alper Erturk
Keyword(s):  
Barium Titanate ◽  
Frequency Response ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Analytical Framework ◽  
Electromechanical Coupling Coefficient ◽  
Sensors And Actuators ◽  
Energy Harvesters ◽  
Size Dependent ◽  
Resonant Dynamics

We establish and analyze an analytical framework by accounting for both the piezoelectric and flexoelectric effects in bimorph cantilevers. The focus is placed on the development of governing electroelastodynamic piezoelectric–flexoelectric equations for the problems of resonant energy harvesting, sensing, and actuation. The coupled governing equations are analyzed to obtain closed-form frequency response expressions via modal analysis. The combined piezoelectric–flexoelectric coupling coefficient expression is identified and its size dependence is explored. Specifically, a typical atomistic value of the flexoelectric constant for barium titanate is employed in the model simulations along with its piezoelectric constant from the existing literature. It is shown that the effective electromechanical coupling of a piezoelectric material, such as barium titanate, is significantly enhanced for thickness levels below 100 nm. The electromechanical coupling coefficient of a barium titanate bimorph cantilever increases from the bulk piezoelectric value of 0.065 to the combined piezoelectric–flexoelectric value exceeding 0.3 toward nanometer thickness level. Electromechanical frequency response functions for resonant power generation and dynamic actuation also capture the size-dependent enhancement of the electromechanical coupling. The analytical framework given here can be used for parameter identification and design of nanoscale cantilevers that can be used as energy harvesters, sensors, and actuators.

scholarly journals FEM Analysis of Various Multilayer Structures for CMOS Compatible Wearable Acousto-Optic Devices

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7863
Author(s):  
Mehwish Hanif ◽  
Varun Jeoti ◽  
Mohamad Radzi Ahmad ◽  
Muhammad Zubair Aslam ◽  
Saima Qureshi ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Figure Of Merit ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Fem Analysis ◽  
Film Structure ◽  
Multilayer Structures ◽  
Electromechanical Coupling Coefficient ◽  
Materials Used ◽  
The Individual

Lately, wearable applications featuring photonic on-chip sensors are on the rise. Among many ways of controlling and/or modulating, the acousto-optic technique is seen to be a popular technique. This paper undertakes the study of different multilayer structures that can be fabricated for realizing an acousto-optic device, the objective being to obtain a high acousto-optic figure of merit (AOFM). By varying the thicknesses of the layers of these materials, several properties are discussed. The study shows that the multilayer thin film structure-based devices can give a high value of electromechanical coupling coefficient (k2) and a high AOFM as compared to the bulk piezoelectric/optical materials. The study is conducted to find the optimal normalised thickness of the multilayer structures with a material possessing the best optical and piezoelectric properties for fabricating acousto-optic devices. Based on simulations and studies of SAW propagation characteristics such as the electromechanical coupling coefficient (k2) and phase velocity (v), the acousto-optic figure of merit is calculated. The maximum value of the acousto-optic figure of merit achieved is higher than the AOFM of all the individual materials used in these layer structures. The suggested SAW device has potential application in wearable and small footprint acousto-optic devices and gives better results than those made with bulk piezoelectric materials.

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