scholarly journals Properties of Car-Embedded Vibrating Type Piezoelectric Harvesting System

2021 ◽  
Vol 11 (16) ◽  
pp. 7449
Author(s):  
Bo-Gun Koo ◽  
Dong-Jin Shin ◽  
Dong-Hwan Lim ◽  
Min-Soo Kim ◽  
In-Sung Kim ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Energy Conversion ◽  
Mechanical Energy ◽  
Variable Mass ◽  
Electrical Energy ◽  
Engine Block ◽  
Operating Frequency ◽  
Maximum Displacement ◽  
Serial Connection ◽  
Piezoelectric Generator

We investigated the harvesting performance of a double piezoelectric generator, which was embedded into the engine block of a small passenger car. The resonance frequency is approximately between 37 and 52 Hz, where the cantilever showed maximum displacement. In reality, the cantilever has a vibrating characteristic, which dramatically reduces displacement, even when the operating frequency deviates slightly from the resonance frequency. To acquire a large mechanical energy-to-electrical energy conversion, a multiple-piezoelectric generator was employed to absorb the energy even when the vibration switched from a resonance to a non-resonance frequency. In this study, a variable mass box was designed and installed in the engine block of a car. The variable mass box consisted of the serial connection of two masses with different weights. The operating frequency deviated from a resonance to a non-resonance frequency within a few hertz (3~4 Hz); the reduction in vibration was lower, leading to a significant acquisition of the resulting power. This is due to the variable matching of the generator, realized by the action of dual mass. This type of generator was installed in the engine block and produced up to 0.038 and 0.357 mW when the engine was operating at 2200 and 3200 rpm, respectively.

Flexoelectric energy harvesters based on Timoshenko laminated beam theory

2017 ◽  
Vol 28 (15) ◽  
pp. 2064-2073 ◽  
Author(s):  
Xu Liang ◽  
Runzhi Zhang ◽  
Shuling Hu ◽  
Shengping Shen
Keyword(s):  
Resonance Frequency ◽  
Energy Conversion ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Mechanical Energy ◽  
Mechanical Vibration ◽  
Beam Theory ◽  
Electrical Energy ◽  
Laminated Beam ◽  
Energy Harvesters

Different from piezoelectricity which is restricted to certain materials, flexoelectricity is a universal electromechanical coupling in all dielectrics. In this work, mechanical energy harvester models were developed based on Timoshenko laminated beam theory, in which the flexoelectric and piezoelectric mechanisms were discussed. For a three-layered energy harvester in parallel configuration, the mechanical vibration energy can be converted into electrical energy due to flexoelectricity, and for the three-layered energy harvester in series configuration, the energy conversion is enhanced by the flexoelectricity. Resonance frequency shifts were observed in the calculations due to flexoelectricity and external circuit resistance. It is found that the electromechanical coupling displayed from the electrical responses versus resonance frequency and resistance. The energy conversion for the three-layered energy harvester system was found to be increased with the decrease in the laminated beam thickness. The energy conversion calculated for different numbers of layers also indicates that laminated energy harvester systems excel single-layered energy harvesters. This work therefore might help in designing flexoelectricity-based energy harvesters.

scholarly journals Effective Mooring Rope Tension in Mechanical and Hydraulic Power Take-Off of Wave Energy Converter

2021 ◽  
Vol 13 (17) ◽  
pp. 9803
Author(s):  
Ji Woo Nam ◽  
Yong Jun Sung ◽  
Seong Wook Cho
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Wave Energy Converter ◽  
Hydraulic Motor ◽  
Energy Converter ◽  
The Individual ◽  
Conversion Efficiencies

The InWave wave energy converter (WEC), which is three-tether WEC type, absorbs wave energy via moored cylindrical buoys with three ropes connected to a terrestrial power take-off (PTO) through a subsea pulley. In this study, a simulation study was conducted to select a suitable PTO when designing a three-tether WEC. The mechanical PTO transfers energy from the buoy to the generator using a gearbox, whereas the hydraulic PTO uses a hydraulic pump, an accumulator, and a hydraulic motor to convert mechanical energy into electrical energy. The hydraulic PTO has a lower energy conversion efficiency than that of the mechanical PTO owing to losses resulting from pipe friction and the individual efficiencies of the hydraulic pumps and motors. However, the efficiencies mentioned above are not the efficiency of the whole system. The efficiency of the whole system should be analyzed considering the tension of the rope and the efficiency of the generator. In this study, the energy conversion efficiencies of the InWave WEC installed the mechanical and hydraulic PTO devices are compared, and their behaviors are analyzed through numerical simulations. The mechanics of mechanical and hydraulic PTO applied to InWave are mathematically expressed, and the issues of the elements constituting the PTO are explained. Finally, factors to consider for PTO selection are presented.

Plane PVDF-Foil Modules for Energy Harvesting of Dynamic Weight Forces

2011 ◽  
Author(s):  
Enrico Bischur ◽  
Norbert Schwesinger
Keyword(s):  
Energy Conversion ◽  
Remanent Polarization ◽  
Piezoelectric Effect ◽  
Mechanical Load ◽  
Mechanical Energy ◽  
Electric Energy ◽  
Electrical Energy ◽  
Pvdf Film ◽  
Layer System ◽  
Dynamic Weight

Plane PVDF-foil modules have been developed and successfully tested that generate electrical energy out of the mechanical energy of dynamic weight forces. For instance electrical energy can be generated, if people or vehicles pass such modules on a ground area. This method is based on the piezoelectric effect of stretched PVDF-foil. The energy conversion of the generator modules was investigated with regard to the remanent polarization of the PVDF material. Furthermore, the influence of the PVDF layer system was investigated on the energy conversion. The measured values are compared with values calculated analytically. It was found that a higher remanent polarization of the PVDF material lead to a better energy conversion. Even more electrical energy could be generated, if more PVDF layers were stacked above each other. If the values were normalized on the PVDF volume used in each case, the values of the electric energy were not constant. However, a maximum was observed at n = 21 layers. The measured energy values were higher than calculated values of the longitudinal piezoelectric effect. This could be caused by a simultaneous expansion of the PVDF film in a direction vertical to the direction of the mechanical load. These generator modules could be used as new energy source for emergency lighting, alarm systems, traffic sensors, etc.

Handedness-controlled and solvent-driven actuators with twisted fibers

2019 ◽  
Vol 6 (6) ◽  
pp. 1207-1214 ◽  
Author(s):  
Bo Fang ◽  
Youhua Xiao ◽  
Zhen Xu ◽  
Dan Chang ◽  
Bo Wang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Conversion Coefficient ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
High Energy ◽  
Polar Solvents ◽  
Start Up

Handedness-controlled actuating systems are constructed from continuous twisted fibers with mirrored handedness, superb flexibility and mechanical robustness, affording impressive start-up torques driven by polar solvents, and controllably outputting rotor kinetic energy, harvesting electrical energy, and delivering mechanical energy with a high energy conversion coefficient.

Piezoelectric generator with nonlinear structure

2021 ◽  
pp. 146442072110086
Author(s):  
Liming Zhou ◽  
Yanbo Liu ◽  
Long Ma ◽  
Yue Wu
Keyword(s):  
Resonance Frequency ◽  
Low Frequency ◽  
Electrical Energy ◽  
Bending Vibration ◽  
Low Frequency Vibration ◽  
Piezoelectric Cantilever ◽  
Piezoelectric Generator ◽  
Ritz Procedure ◽  
Tip Mass ◽  
Euler Bernoulli Beam

Motion in nature is usually a low-frequency vibration such as walking, running, swinging arms, and so on, but traditional piezoelectric cantilever structures are inefficient at harvesting energy from low-frequency vibrations. T in the environment. To overcome this, a novel piezoelectric generator was designed. A cantilevered bimorph with a tip mass and a pair of preloading springs were fixed on its base to form a nonlinear piezoelectric generator. The energy transmission in the structure was analyzed. The harvester was modeled as a Euler–Bernoulli beam, and the piezoelectric material was assumed to be linear. The bending vibration was calculated using the Rayleigh–Ritz procedure, and the frequency characteristics of the output voltage were analyzed under different preloading distances. It was found that changing the preloading of the spring helped reduce the natural frequency of the cantilever, which facilitated conversion of ambient low-frequency vibrations into electrical energy. Then, the characteristics of low frequency energy harvesting were investigated experimentally. The theoretical results were consistent with the experimental data; moreover, the resonance frequency, which changes with the preloading distance, reduced from 43 to 35 Hz when the preloading distance was increased from 0 to 1 mm. In this paper, an effective structure to control the resonant frequency is proposed and its motion equation stated. The structure has potential for applications in predicting the effect of preloading distance on resonance frequency.

Key Issues on Flextensional Piezoelectric Energy Harvester Developments

2019 ◽  
Author(s):  
Tian-Bing Xu ◽  
Lei Zuo
Keyword(s):  
Dipole Moment ◽  
Energy Storage ◽  
Energy Conversion ◽  
Energy Harvester ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Storage Efficiency ◽  
Energy Storage Efficiency

Abstract A “33” mode (mechanical stress being in parallel to the electric dipole moment direction) piezoelectric lead zirconate titanate (PZT) multilayer stack-based piezoelectric flextensional energy harvester (PZT-Stacked-FEH) has been developed. Interdisciplinary approaches had been taken to increase the performance of the PZT-Stacked-FEH. First, an elastic flextensional frame for force amplification has been optimally designed to capture more mechanical energy with high energy transition efficiency into the PZT-Stacked-FEH. Second, a “33” mode piezoelectric PZT multilayer stack (PZT-Stack) was employed instead of “31” mode (stress being in perpendicular to the dipole moment direction) single layer piezoelectric component to increase mechanical to electrical energy conversion efficiency and to generate more electrical charges in order to improve energy storage efficiency. With these approaches, the PZT-Stacked-FEH demonstrates excellent performance: 1) a 19% of overall mechanical to electrical energy conversion efficiency was achieved, 2) 48.6 times more mechanical energy was transited into PZT-Stacked-FEH and 26.5 times more electrical power was generated than directly applying force to the PZT-stack, and 3) energy storage efficiency was significantly improved. In this paper, we are focusing on the investigations for the off-resonance mode performance of the PZT-Stacked-FEH through theoretical modeling, prototype development, and experimental studies. A prototype PZT-Stacked-FEH of weight 18 grams was able to generate 666 mW electrical power under 52 Nrms force at 250 Hz, which is much lower than the resonant frequency (936 Hz). At this condition, a 6,600 μF super-capacitor was charged from 0 to 7 V in 1.6 second, at an average rate of 100 mW. Furthermore, 70% of generated appear electrical powers were delivered to matched resistive loads in the investigated regime of frequencies. Finally, the experimental results matched well with theoretical predictions which verified the developed theoretical models.

Feasibility Study on Wave Energy Conversion by a Modified Oscillating Water Column Device

2015 ◽  
Vol 787 ◽  
pp. 8-12
Author(s):  
V.P. Mohandas ◽  
R. Wilbert ◽  
S.S. Saji ◽  
Laiju Lukose
Keyword(s):  
Energy Conversion ◽  
Water Column ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Ocean Waves ◽  
Oscillating Water Column ◽  
Model Studies ◽  
World Energy ◽  
Model Device ◽  
Double Chamber

Energy conversion from ocean waves has become the need of the hour in view of the renewable energy awakening occurring all over the world. Energy conversion by Oscillating Water Column (OWC) concept has become an established technology in converting mechanical energy of ocean waves to electrical energy. But the limitations of OWC concept calls for further research and developments to make the technology commercially an attractive one. In this context Boccotti, the Italian scientist advanced the double chamber concept and the implications of the concept still remains to be investigated through model studies. This paper presents the details of a generic study carried out in a physical model device under regular waves.

scholarly journals Wind power plant resilience

2010 ◽  
Vol 14 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Naim Afgan ◽  
Dejan Cvetinovic
Keyword(s):  
Power Plant ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Wind Power ◽  
Wind Velocity ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Wind Power Plant ◽  
Electricity Cost ◽  
Resilience Index

A wind energy system transforms the kinetic energy of wind into mechanical or electrical energy that can be harnessed for practical use. Mechanical energy is most commonly used for pumping water in rural or remote locations. Electrical energy is obtained by connecting wind turbine with the electricity generator. The performance of the wind power plant depends on the wind kinetic energy. It depends on the number of design parameter of the wind turbine. For the wind power plant the wind kinetic energy conversion depends on the average wind velocity, mechanical energy conversion into electricity, and electricity transmission. Resilience of the wind power plant is the capacity of the system to withstand changes of the following parameters: wind velocity, mechanical energy conversion into electricity, electricity transmission efficiency and electricity cost. Resilience index comprise following indicators: change in wind velocity, change in mechanical energy conversion efficiency, change in conversion factor, change in transmission efficiency, and change in electricity cost. The demonstration of the resilience index monitoring is presented by using following indicators, namely: average wind velocity, power production, efficiency of electricity production, and power-frequency change. In evaluation of the resilience index of wind power plants special attention is devoted to the determination of the resilience index for situation with priority given to individual indicators.

scholarly journals The Energy Conversion behind Micro-and Nanomotors

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 222
Author(s):  
Yingmeng Wang ◽  
Yingfeng Tu ◽  
Fei Peng
Keyword(s):  
Energy Conversion ◽  
Environmental Remediation ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
External Environment ◽  
Electrical Energy ◽  
Power Devices ◽  
The Past ◽  
Targeted Drug ◽  
Application Prospects

Inspired by the autonomously moving organisms in nature, artificially synthesized micro-nano-scale power devices, also called micro-and nanomotors, are proposed. These micro-and nanomotors that can self-propel have been used for biological sensing, environmental remediation, and targeted drug transportation. In this article, we will systematically overview the conversion of chemical energy or other forms of energy in the external environment (such as electrical energy, light energy, magnetic energy, and ultrasound) into kinetic mechanical energy by micro-and nanomotors. The development and progress of these energy conversion mechanisms in the past ten years are reviewed, and the broad application prospects of micro-and nanomotors in energy conversion are provided.

scholarly journals Methods to Improve Energy Conversion Efficiency of Dielectric Elastomer Generators

2019 ◽  
Vol 804 ◽  
pp. 63-67
Author(s):  
Heng Tong Cheng ◽  
Zhen Qiang Song ◽  
Shijie Zhu ◽  
Kazuhiro Ohyama
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Input Voltage ◽  
Energy Conversion Efficiency ◽  
Stretch Ratio ◽  
Dielectric Elastomer ◽  
Conversion Performance ◽  
Ratio Range

Dielectric elastomer generators (DEGs) are based on the electromechanical response of the dielectric elastomer film sandwiched between the compliant electrodes on each side, which are capable of converting mechanical energy from diverse sources (e.g, ocean wave) into electrical energy. In essence, DEG is a voltage up-converter using mechanical energy to increase the electrical energy of the charge on a soft capacitor. We evaluated the effect of input voltage and the pre-stretch ratios on energy conversion efficiency of DEG. With a power supply of 2.2kV and pre-stretch ratio of 2, the maximum net electrical energy density and energy conversion efficiency in a single harvesting cycle were measured to be 413 J/kg and 15.8%, respectively. The experimental results showed that, with the higher input voltage and the larger stretch ratio range, higher the energy conversion performance of DEG can be achieved.

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