Microscale electrostatic energy harvester using internal impacts

2012 ◽  
Vol 23 (13) ◽  
pp. 1409-1421 ◽  
Author(s):  
Cuong P Le ◽  
Einar Halvorsen ◽  
Oddvar Søråsen ◽  
Eric M Yeatman
Keyword(s):  
Energy Harvesting ◽  
Output Power ◽  
Inertial Mass ◽  
Electrostatic Energy ◽  
Mass Motion ◽  
Total Output ◽  
Additional Energy ◽  
Impact Device ◽  
Reference Device ◽  
The Impact

This article presents a new concept for electrostatic energy harvesting devices that increase output power under displacement limited inertial mass motion at sufficiently large acceleration amplitudes. The concept is illustrated by two demonstrated electrostatic energy harvesting prototypes in the same die dimension: a reference device with end-stops and an impact device with movable end-stops functioning as slave transducers. Both devices are analyzed and characterized in small and large excitation regimes. We found that significant additional energy from the internal impact force can be harvested by the slave transducer. The impact device gives much higher, up to a factor of 3.7, total output power than the reference device at the same high-acceleration amplitude. The bandwidth of the response to frequency sweeps is beneficially enlarged by up to a factor of 20 by the nonlinear mechanisms of the impact device.

Study of an Impact Driven Frequency Up-Conversion Piezoelectric Harvester

2017 ◽  
Author(s):  
Amin Abedini ◽  
Saeed Onsorynezhad ◽  
Fengxia Wang
Keyword(s):  
Energy Harvesting ◽  
Output Power ◽  
Power Efficiency ◽  
Constitutive Law ◽  
Flexible Beam ◽  
Nonlinear Phenomena ◽  
Base Excitation ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam ◽  
The Impact

Frequency up-conversion is an effective way to increase the output power from a piezoelectric beam, which converts the ambient low-frequency vibration to the resonant vibration of the piezoelectric energy harvesters (PEH) to achieve high electric power output. Frequency up-conversion technologies are realized via impact or non-impact magnetic force to mediate the interaction between the driving beam and the generating beam. Most studies focus on the either linear model prediction or experimental verification of the linear analysis. Few, if any, study the effects of the impact induced nonlinear phenomena on power generation efficiency. In this work, we investigate how to use discontinuous theory to improve the power efficiency of the frequency up-conversion process caused by impacts. The energy harvesting performance of a piezoelectric beam in interaction with a softer beam in periodic motion is studied. The discontinuous dynamical system theory is applied to this problem to study the piezoelectric behavior under periodic motions and its bifurcations. The beams are modeled with two spring-mass-damper systems, and the analytical model of the piezoelectric beam is created based on the linear mechanical-electrical constitutive law of the piezoelectric material, and the linear elastic constitutive law of the substrate. Based on the theoretical model, the analytical solution of the output power is derived in terms of the vibration amplitude, frequency, and the electrical load. The soft beam is subjected to a sinusoidal base excitation, and the impacts of the more flexible beam excite the piezoelectric beam. The performance of the energy harvesting of period one and period two motions have been studied and bifurcation trees for impact velocities, times, displacements and harvested power versus the frequency of the base excitation are obtained.

Periodic Solutions of an Impact-Driven Frequency Up-Conversion Piezoelectric Harvester

2019 ◽  
Vol 29 (10) ◽  
pp. 1930029 ◽  
Author(s):  
Amin Abedini ◽  
Saeed Onsorynezhad ◽  
Fengxia Wang
Keyword(s):  
Power Generation ◽  
Energy Harvesting ◽  
Periodic Solutions ◽  
Output Power ◽  
Power Efficiency ◽  
Low Frequency ◽  
Base Excitation ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam ◽  
The Impact

Frequency up-conversion has been proved to be an effective approach to increase the output power of a piezoelectric energy harvester (PEH). The proposed system can convert low-frequency vibration from ambient sources to the resonant vibration of the PEH hence can improve the output power efficiency. Frequency up-conversion technologies are introduced via impact or nonimpact magnetic forces to initiate the repeated free oscillations of the piezoelectric generator. No matter impact- or nonimpact-driven PEHs, most studies focus on either finite element simulation or experimental demonstration of PEHs electric power generations. Few, if any, study the effects of the impact-induced discontinuous dynamics on power generation efficiency. In this work, the energy harvesting performance of a piezoelectric beam upon interaction with a softer driving beam was studied. The discontinuous dynamics behind this impact-driven PEH was investigated, and strategies exploited to further improve the power efficiency of the frequency up-conversion process. Based on the linear elastic and linear mechanical-electrical constitutive laws, the lumped parameter models were built for both the driving beam and the piezoelectric driven beam. The numerical solution of the output power is obtained based on the vibration amplitude, frequency, and the electrical load. The soft beam is subjected to a sinusoidal base excitation, and the piezoelectric beam was excited via impacting with the soft driving beam. Based on the discontinuous dynamics theory, the performance of the energy harvesting of the impact-driven system was studied for period-1 and period-2 motions. Based on the stability and bifurcation analysis of periodic solutions, bifurcation diagrams of impact velocities, times, displacements and harvested power versus the frequency of the base excitation were also obtained, and compared to the power generation of a piezoelectric beam with base excitation.

scholarly journals Advection-Based Coordinated Control for Wave-Energy Converter Array

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3567
Author(s):  
Hong Li ◽  
Bo Zhang ◽  
Li Qiu ◽  
Shiyu Chen ◽  
Jianping Yuan ◽  
...  
Keyword(s):  
Output Power ◽  
Wave Energy ◽  
Control Method ◽  
Initial Conditions ◽  
Coordinated Control ◽  
Wave Energy Converter ◽  
Total Output ◽  
Energy Converter ◽  
Storage Unit ◽  
Additional Energy

This paper presents a coordinated control based on the advection consensus control algorithm to implement power dispatch for each wave-energy converter (WEC) in a WEC array. Under unbalanced conditions, the proposed algorithm is applied in order to control each WEC to output power coordinately, to enable the total output power of the WEC array to satisfy the time-varying load requirements. The purpose of the additional energy storage unit on each WEC is to smooth the power output of each WEC and to obtain more margin. Case studies include the demonstration of some simulations and experiments, and the results show that the WEC array under the proposed control method can accurately respond to the demand for power supply under unbalanced initial conditions.

Total output power variation of several small wind turbines

2020 ◽  
pp. 0309524X2090798
Author(s):  
Kenta Kashiwaya ◽  
Junji Kondoh ◽  
Kakuru Funabashi
Keyword(s):  
Power Systems ◽  
Output Power ◽  
Wind Turbines ◽  
Low Voltage ◽  
Correlation Coefficients ◽  
Total Output ◽  
Smoothing Effect ◽  
Small Wind Turbines ◽  
Voltage Flicker ◽  
The Impact

There is a concern that connection of several small wind turbines may cause severe voltage fluctuation and voltage flicker in low-voltage distribution lines due to their output power variations. In this study, output power variations of four 5-kW-class small wind turbine systems were measured with an interval of 0.1 s at a site in Wakkanai, Hokkaido, and their correlations and smoothing effect in the frequency range from [Formula: see text] to 5 Hz were analyzed and compared with those of five residential photovoltaic power systems. The results indicate that a smoothing effect occurs more in small wind turbines than in photovoltaic systems, because of lower correlation coefficients in lower frequency ([Formula: see text] Hz) components. Voltage flicker at the point of common coupling was also measured and it was confirmed that the impact of small wind turbines on voltage flicker is low enough at the site. In addition, the upper limits of the installation number and/or the system resistance are estimated theoretically using the measured flicker values.

scholarly journals Modeling, Validation, and Performance of Two Tandem Cylinder Piezoelectric Energy Harvesters in Water Flow

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 872
Author(s):  
Rujun Song ◽  
Chengwei Hou ◽  
Chongqiu Yang ◽  
Xianhai Yang ◽  
Qianjian Guo ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Output Power ◽  
Water Flow ◽  
Energy Harvester ◽  
Beat Frequency ◽  
Maximum Output Power ◽  
Total Output ◽  
Maximum Output ◽  
Energy Harvesters ◽  
Piezoelectric Energy

This paper studies a novel enhanced energy-harvesting method to harvest water flow-induced vibration with a tandem arrangement of two piezoelectric energy harvesters (PEHs) in the direction of flowing water, through simulation modeling and experimental validation. A mathematical model is established by two individual-equivalent single-degree-of-freedom models, coupled with the hydrodynamic force obtained by computational fluid dynamics. Through the simulation analysis, the variation rules of vibration frequency, vibration amplitude, power generation and the distribution of flow field are obtained. And experimental tests are performed to verify the numerical calculation. The experimental and simulation results show that the upstream piezoelectric energy harvester (UPEH) is excited by the vortex-induced vibration, and the maximum value of performance is achieved when the UPEH and the vibration are resonant. As the vortex falls off from the UPEH, the downstream piezoelectric energy harvester (DPEH) generates a responsive beat frequency vibration. Energy-harvesting performance of the DPEH is better than that of the UPEH, especially at high speed flows. The maximum output power of the DPEH (371.7 μW) is 2.56 times of that of the UPEH (145.4 μW), at a specific spacing between the UPEN and the DPEH. Thereupon, the total output power of the two tandem piezoelectric energy harvester systems is significantly greater than that of the common single PEH, which provides a good foreground for further exploration of multiple piezoelectric energy harvesters system.

RESEARCH OF THE IMPACT DEVICE MODEL OF THE ROD TYPE BY DIFFERENCE METHOD

2020 ◽  
pp. 73-80
Author(s):  
А.М. Слиденко ◽  
В.М. Слиденко
Keyword(s):  
Boundary Value Problem ◽  
Difference Method ◽  
Model Problem ◽  
Boundary Value ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Cross Sectional ◽  
Impact Device ◽  
Initial Boundary Value ◽  
The Impact

Приводится анализ механических колебаний элементов ударного устройства с помощью модели стержневого типа. Ударник и инструмент связаны упругими и диссипативными элементами, которые имитируют их взаимодействие. Аналогично моделируется взаимодействие инструмента с рабочей средой. Сформулирована начально-краевая задача для системы двух волновых уравнений с учетом переменных поперечных сечений стержней. Площади поперечных сечений определяются параметрическими формулами при сохранении объемов стержней. Параметрические формулы позволяют получать различного вида зависимости площади поперечного сечения стержня от его длины. Начальные условия отражают физическую картину взаимодействия инструмента с ударником и рабочей средой. Краевые условия описывают контактные взаимодействия ударника с инструментом и последнего с рабочей средой. В качестве модельной задачи рассматривается соударение ударника и инструмента через элемент большой жесткости. Начально-краевая задача исследуется разностным методом. Проводится сравнение решений задачи, полученных с помощью двухслойной и трехслойной разностных схем. Такие схемы реализованы в общей компьютерной программе в системе Mathcad. Показано, что при вычислениях распределения нормальных напряжений по длине стержня лучшими свойствами относительно устойчивости обладает двухслойная схема The article gives the analysis of mechanical vibrations of the impact device elements using the model of the rod type. The hammer and the tool are connected by elastic and dissipative elements that simulate their interaction. The interaction of the tool with the processing medium is simulated in a similar way. An initial boundary-value problem is formulated for a system of two wave equations taking into account the variable cross sections of the rods. Cross-sectional areas are determined by parametric formulas maintaining the volume of the rods. Parametric formulas allow one to obtain various dependence types of the cross-sectional area of the rod on its length. The initial and boundary conditions reflect the physical phenomenon of the tool interaction with the processing medium, and also describe the contact interactions of the hammer with the tool. The impacting of the hammer and the tool through an element of high rigidity is considered as a model problem. To control the limiting values, the solution of the model problem by the Fourier method is used. The initial-boundary-value problem is investigated by the difference method. A comparison of solutions obtained for the two-layer and three-layer difference schemes is given. Such schemes are realized in a common computer program in the Mathcad. It is shown that the two-layer scheme has the best properties in relation to stability while calculating the distribution of normal voltage along the length of the rod

scholarly journals An Optimized Flutter-Driven Triboelectric Nanogenerator with a Low Cut-In Wind Speed

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 366
Author(s):  
Yang Xia ◽  
Yun Tian ◽  
Lanbin Zhang ◽  
Zhihao Ma ◽  
Huliang Dai ◽  
...  
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Energy Harvesting ◽  
Wind Energy ◽  
Output Power ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Triboelectric Nanogenerator ◽  
Vibration Behavior ◽  
Air Speed

We present an optimized flutter-driven triboelectric nanogenerator (TENG) for wind energy harvesting. The vibration and power generation characteristics of this TENG are investigated in detail, and a low cut-in wind speed of 3.4 m/s is achieved. It is found that the air speed, the thickness and length of the membrane, and the distance between the electrode plates mainly determine the PTFE membrane’s vibration behavior and the performance of TENG. With the optimized value of the thickness and length of the membrane and the distance of the electrode plates, the peak open-circuit voltage and output power of TENG reach 297 V and 0.46 mW at a wind speed of 10 m/s. The energy generated by TENG can directly light up dozens of LEDs and keep a digital watch running continuously by charging a capacitor of 100 μF at a wind speed of 8 m/s.

2D electrostatic energy harvesting device using a single shallow arched microbeam

2021 ◽  
pp. 103700
Author(s):  
Mohamed Amin Ben Hassena ◽  
Hatem Samaali ◽  
Hassen M. Ouakad ◽  
Fehmi Najar
Keyword(s):  
Energy Harvesting ◽  
Electrostatic Energy

scholarly journals On The Contribution of Interest Expense (Income) on Total Output

2021 ◽  
Vol 4 (1) ◽  
pp. 31-56
Author(s):  
Ahmed Mehedi Nizam
Keyword(s):  
Interest Rate ◽  
Aggregate Demand ◽  
Total Output ◽  
Response Analysis ◽  
Panel Var ◽  
Intuitive Reasoning ◽  
Body Of Knowledge ◽  
Interest Income ◽  
Structural Panel ◽  
The Impact

Abstract A decrease in interest rate in traditional view of monetary policy transmission is linked to a lower cost of borrowing which eventually results into a greater spending in investment and a bigger GDP. However, a decrease in interest rate is also linked to a decrease in interest income which, in turn, affects the aggregate demand and total GDP. So far, no concerted effort has been made to investigate this positive inter-relation between interest income and GDP in the existing literature. Here in the first place we intuitively describe the inter-relation between interest income and output and then provide a micro-foundation of our intuitive reasoning in the context of a small endowment economy with finitely-lived identical households. Then we try to uncover the impact of nominal interest income on the macroeconomy using multiplier theory for a panel of some 04 (four) OECD countries. We define and calculate the corresponding multiplier values algebraically and then we empirically measure them using impulse response analysis under structural panel VAR framework. Large, consistent and positive values of the cumulative multipliers indicate a stable positive relationship between nominal interest income and output. Moreover, variance decomposition of GDP shows that a significant portion of the variance in GDP is attributed to interest income under VAR/VECM framework. Finally, we have shown how and where our analysis fits into the existing body of knowledge.

scholarly journals Improved agreement and diagnostic accuracy of a cuffless 24-h blood pressure measurement device in clinical practice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thenral Socrates ◽  
Philipp Krisai ◽  
Annina S. Vischer ◽  
Andrea Meienberg ◽  
Michael Mayr ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Pressure Measurement ◽  
Area Under The Curve ◽  
Pulse Transit Time ◽  
Hypertension Detection ◽  
Software Update ◽  
Reference Device ◽  
Cuffless Blood Pressure ◽  
The Impact ◽  
Blood Pressure Measurement Device

AbstractA cuffless blood pressure (BP) device (TestBP) using pulse transit time is in clinical use, but leads to higher BP values compared to a cuff-based 24 h-BP reference device (RefBP). We evaluated the impact of a recent software update on BP results and TestBP’s ability to differentiate between normo- and hypertension. 71 individuals had TestBP (Somnotouch-NIBP) and RefBP measurements simultaneously performed on either arm. TestBP results with software version V1.5 were compared to V1.4 and RefBP. Mean 24 h (± SD) BP for the RefBP, TestBP-V1.4 and TestBP-V1.5 were systolic 134.0 (± 17.3), 140.8 (± 20) and 139.1 (± 20) mmHg, and diastolic 79.3 (± 11.7), 85.8 (± 14.1) and 83.5 (± 13.0) mmHg, respectively (p-values < 0.001). TestBP-V1.5 area under the curve (95% confidence interval) versus RefBP for hypertension detection was 0.92 (0.86; 0.99), 0.94 (0.88; 0.99) and 0.77 (0.66; 0.88) for systolic and 0.92 (0.86; 0.99), 0.92 (0.85; 0.99) and 0.84 (0.74; 0.94) for diastolic 24 h, awake and asleep BP respectively. TestBP-V1.5 detected elevated systolic/diastolic mean 24 h-BP with a 95%/90% sensitivity and 65%/70% specificity. Highest Youden’s Index was systolic 133 (sensitivity 95%/specificity 80%) and diastolic 87 mmHg (sensitivity 81%/specificity 98%). The update improved the agreement to RefBP. TestBP was excellent for detecting 24 h and awake hypertensive BP values but not for asleep BP values.

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