scholarly journals Harvest of Motion

2008 ◽  
Vol 130 (09) ◽  
pp. 56-58 ◽  
Author(s):  
Brian S. Hendrickson ◽  
Stuart B. Brown

This article discusses that a small-scale generator uses a catch-and-release strategy that can turn a casual stroll into useful electric energy. Many devices now require fractions of a watt continuously, often with occasional bursts of 1 to 10 W during peak activity. However, batteries occupy device volume and have limited life. Even rechargeable batteries can withstand only a finite number of charge cycles and, perhaps most important, recharging them can be inconvenient or expensive. Engineers must develop strategies to harness the abundant energy in low-frequency, time-varying motion before energy harvesting can achieve its greatest potential. Water waves, swaying and bouncing structures, and biomechanics are potential environmental energy sources that are largely out of the reach of the current vibration-inspired, motion harvesting technologies. Being able to economically convert low-speed motion to electricity will be a key to realizing practical long-term power generation for distributed devices. The Veryst energy-harvesting concept is one approach that intends to do just that. As with other energy harvesting projects, much work remains, but initial research and development suggest strong potential.

Author(s):  
Brian S. Hendrickson ◽  
Stuart B. Brown

Small-scale motion energy harvesting has garnered significant interest in recent years, especially given advances in piezoelectric materials, but with limited commercial application. Most harvesting methods to date, including those employing magnetic induction, have focused on coupled resonance. Such harvesters are tuned to resonate with their excitation source and have shown promise in capturing moderately high-frequency (>10Hz), low-displacement motion that is steady. However, coupled harvesters lose efficiency significantly when a source deviates slightly in frequency. They also require large masses and/or buoyant volumes to efficiently capture low frequency (<10Hz) motion. We have been developing a novel technology that combines electromagnetic induction with a proprietary catch-and-release mechanism that absorbs an input motion and then releases it at a much higher frequency to improve conversion efficiency. The energy harvester is simple, compact, and insensitive to excitation frequency. Initial prototypes have demonstrated power densities and specific powers many multiples greater than the best-performing, commercial vibration harvester. We have also developed a validated computer model of the system that indicates that performance could be improved 2–4 times over initial prototypes.


Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 598 ◽  
Author(s):  
Kwangseok Lee ◽  
Jeong-won Lee ◽  
Kihwan Kim ◽  
Donghyeon Yoo ◽  
Dong Kim ◽  
...  

Water waves are a continuously generated renewable source of energy. However, their random motion and low frequency pose significant challenges for harvesting their energy. Herein, we propose a spherical hybrid triboelectric nanogenerator (SH-TENG) that efficiently harvests the energy of low frequency, random water waves. The SH-TENG converts the kinetic energy of the water wave into solid–solid and solid–liquid triboelectric energy simultaneously using a single electrode. The electrical output of the SH-TENG for six degrees of freedom of motion in water was investigated. Further, in order to demonstrate hybrid energy harvesting from multiple energy sources using a single electrode on the SH-TENG, the charging performance of a capacitor was evaluated. The experimental results indicate that SH-TENGs have great potential for use in self-powered environmental monitoring systems that monitor factors such as water temperature, water wave height, and pollution levels in oceans.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Zhongsheng Chen ◽  
Jing He ◽  
Gang Wang

Embedded wireless sensing networks (WSNs) provide effective solutions for structural health monitoring (SHM), where how to provide long-term electric power is a bottle-neck problem. Piezoelectric vibration energy harvesting (PVEH) has been widely studied to realize self-powered WSNs due to piezoelectric effect. Structural vibrations are usually variable and exist in the form of elastic waves, so cantilever-like harvesters are not appropriate. In this paper, one kind of two-dimensional (2D) piezoelectric metamaterial plates with local resonators (PMP-LR) is investigated for structural vibration energy harvesting. In order to achieve low-frequency and broadband PVEH in SHM, it is highly necessary to study dynamic characteristics of PMP-LR, particularly bandgaps. Firstly, an analytical model is developed based on the Kirchhoff plate theory, and modal analysis is done by using the Rayleigh–Ritz method. Then, effects of geometric and material parameters on vibration bandgaps are analyzed by finite element-based simulations. In the end, experiments are carried out to validate the simulated results. The results demonstrate that the location of bandgaps can be easily adjusted by the design of local resonators. Therefore, the proposed method will provide an effective tool for optimizing local resonators in PMP-LR.


2021 ◽  
Vol 4 (1) ◽  
pp. 43
Author(s):  
Tigran Avetissian ◽  
Fabien Formosa ◽  
Adrien Badel ◽  
Michel Demuynck ◽  
Aidin Delnavaz ◽  
...  

The mechanical deformation of the ear canal induced by the temporomandibular joint movement constitutes a promising source of energy to power in-ear devices (hearing aids, communication earpieces, etc.). The large morphological variability of the human ear canal and its intrinsic dynamic characteristics—with displacement frequencies below 1.5 Hz with an average volume variation of 60 mm3—motivate the development of non-conventional dedicated energy harvesting methods. This paper demonstrates the concept and design of a modular hydraulic–piezoelectric self-actuated frequency up-conversion micromachine for energy harvesting. The mechanical energy is conveyed using a liquid-filled custom fitted earplug, which can be considered as a hydraulic pump. A hydraulic circuit composed of a pressure amplifier, two driven valves and two check valves allows to drive two micro-pistons. These micro-pistons actuate a bistable oscillator associated to a piezoelectric transducer allowing the low frequency mechanical excitation to be efficiently converted into electric energy through frequency-up conversion. The two integrated passively driven valves are based on tube buckling and allow the pistons to act alternatively on the oscillator to generate a backward and forward run for two jaw movements. A complete theoretical multiphysics model of the machine has been established for the design and evaluation of the potential of the proposed approach. Global analytical and refined FEM approaches have been combined to integrate the fluid and mechanical behaviors. Based on simulation and preliminary experimental data, the harvested energy is expected to be 8 µJ for one jaw closing, with a theoretical 40% end-to-end conversion efficiency.


2019 ◽  
Vol 4 (1) ◽  
pp. 3-39 ◽  
Author(s):  
Shashank Priya ◽  
Hyun-Cheol Song ◽  
Yuan Zhou ◽  
Ronnie Varghese ◽  
Anuj Chopra ◽  
...  

Abstract Piezoelectric microelectromechanical systems (PiezoMEMS) are attractive for developing next generation self-powered microsystems. PiezoMEMS promises to eliminate the costly assembly for microsensors/microsystems and provide various mechanisms for recharging the batteries, thereby, moving us closer towards batteryless wireless sensors systems and networks. In order to achieve practical implementation of this technology, a fully assembled energy harvester on the order of a quarter size dollar coin (diameter=24.26 mm, thickness=1.75 mm) should be able to generate about 100 μW continuous power from low frequency ambient vibrations (below 100 Hz). This paper reviews the state-of-the-art in microscale piezoelectric energy harvesting, summarizing key metrics such as power density and bandwidth of reported structures at low frequency input. This paper also describes the recent advancements in piezoelectric materials and resonator structures. Epitaxial growth and grain texturing of piezoelectric materials is being developed to achieve much higher energy conversion efficiency. For embedded medical systems, lead-free piezoelectric thin films are being developed and MEMS processes for these new classes of materials are being investigated. Non-linear resonating beams for wide bandwidth resonance are also reviewed as they would enable wide bandwidth and low frequency operation of energy harvesters. Particle/granule spray deposition techniques such as aerosol-deposition (AD) and granule spray in vacuum (GSV) are being matured to realize the meso-scale structures in a rapid manner. Another important element of an energy harvester is a power management circuit, which should maximize the net energy harvested. Towards this objective, it is essential for the power management circuit of a small-scale energy harvester to dissipate minimal power, and thus it requires special circuit design techniques and a simple maximum power point tracking scheme. Overall, the progress made by the research and industrial community has brought the energy harvesting technology closer to the practical applications in near future.


2015 ◽  
Vol 757 ◽  
pp. 171-174
Author(s):  
Kai Zhou ◽  
Fang Xie ◽  
Yi Tao ◽  
Hai Xia Du

Ambient energy harvesting has been in recent years the recurring object of a number of research efforts aimed at providing an autonomous solution to the powering of small scale electronic mobile devices. Among the different solutions, vibration energy harvesting has played a major role due to the almost universal presence of mechanical vibrations. In the paper, a piezoelectric cantilever device for harvesting the ambient low-frequency vibration energy is designed, and influences of its structure on output voltage and power generation capacity are studied also. The study results show that the piezoelectric cantilever can produce enough power energy which meets the operation requirements of sensors in wireless networks. It provides a method and corresponding theoretical basis for the harvesting of ambient low-frequency vibration energy and the design of self-supply devices for sensors in wireless networks.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
João V. Vidal ◽  
Vladislav Slabov ◽  
Andrei L. Kholkin ◽  
Marco P. Soares dos Santos

AbstractMotion-driven electromagnetic-triboelectric energy generators (E-TENGs) hold a great potential to provide higher voltages, higher currents and wider operating bandwidths than both electromagnetic and triboelectric generators standing alone. Therefore, they are promising solutions to autonomously supply a broad range of highly sophisticated devices. This paper provides a thorough review focused on major recent breakthroughs in the area of electromagnetic-triboelectric vibrational energy harvesting. A detailed analysis was conducted on various architectures including rotational, pendulum, linear, sliding, cantilever, flexible blade, multidimensional and magnetoelectric, and the following hybrid technologies. They enable highly efficient ways to harvest electric energy from many forms of vibrational, rotational, biomechanical, wave, wind and thermal sources, among others. Open-circuit voltages up to 75 V, short-circuit currents up to 60 mA and instantaneous power up to 144 mW were already achieved by these nanogenerators. Their transduction mechanisms, including proposed models to make intelligible the involved physical phenomena, are also overviewed here. A comprehensive analysis was performed to compare their respective construction designs, external excitations and electric outputs. The results highlight the potential of hybrid E-TENGs to convert unused mechanical motion into electric energy for both large- and small-scale applications. Finally, this paper proposes future research directions toward optimization of energy conversion efficiency, power management, durability and stability, packaging, energy storage, operation input, research of transduction mechanisms, quantitative standardization, system integration, miniaturization and multi-energy hybrid cells.


Author(s):  
Arata Masuda ◽  
Yasuhiro Hiraki ◽  
Naoto Ikeda ◽  
Akira Sone

In this study, a design of an energy harvesting damper for low-frequency applications, such as energy harvesting from long period infrastructures, tanks and pipings, and maritime and offshore structures, is presented. In this design, the low-frequency relative motion of the damper is transformed into a high-frequency motion of a piezoelectric cantilever beam by a mechanical switching mechanism, referred to as “plucking” mechanism that couples and decouples the cantilever to the damper rod so that the input energy into the damper is converted to electric energy with high efficiency. In this paper, the energy harvesting efficiency is theoretically calculated for the harvesters with and without plucking mechanism and the optimized maximum performance is derived. Then the electrical switching circuit for the enhancement of the electromechanical conversion efficiency, referred to as “SSHI” interface is introduced. Numerical case studies suggest that the harvester with an ideally implemented parallel SSHI circuit can retrieve over 70 % energy of the maximum mechanical work input on the damper rod.


2019 ◽  
Vol 624 ◽  
pp. A22 ◽  
Author(s):  
J. Y. Donner ◽  
J. P. W. Verbiest ◽  
C. Tiburzi ◽  
S. Osłowski ◽  
D. Michilli ◽  
...  

Context. High-precision pulsar-timing experiments are affected by temporal variations of the dispersion measure (DM), which are related to spatial variations in the interstellar electron content and the varying line of sight to the source. Correcting for DM variations relies on the cold-plasma dispersion law which states that the dispersive delay varies with the squared inverse of the observing frequency. This may, however, give incorrect measurements if the probed electron content (and therefore the DM) varies with observing frequency, as is predicted theoretically due to the different refraction angles at different frequencies. Aims. We study small-scale density variations in the ionised interstellar medium. These structures may lead to frequency-dependent DMs in pulsar signals. Such an effect could inhibit the use of lower-frequency pulsar observations as tools to correct time-variable interstellar dispersion in higher-frequency pulsar-timing data. Methods. We used high-cadence, low-frequency observations with three stations from the German LOng-Wavelength (GLOW) consortium, which are part of the LOw-Frequency ARray (LOFAR). Specifically, 3.5 yr of weekly observations of PSR J2219+4754 are presented. Results. We present the first detection of frequency-dependent DMs towards any interstellar object and a precise multi-year time-series of the time- and frequency-dependence of the measured DMs. The observed DM variability is significant and may be caused by extreme scattering events. Potential causes for frequency-dependent DMs are quantified and evaluated. Conclusions. We conclude that frequency dependence of DMs has been reliably detected and is indeed caused by small-scale (up to tens of AUs) but steep density variations in the interstellar electron content. We find that long-term trends in DM variability equally affect DMs measured at both ends of our frequency band and hence the negative impact on long-term high-precision timing projects is expected to be limited.


Author(s):  
S. G. Obukhov ◽  
I. A. Plotnikov ◽  
V. G. Masolov

The paper presents the results of the comparative analysis of operation modes of an autonomous hybrid power complex with/without the energy store. We offere the technique which defines the power characteristics of the main components of a hybrid power complex: the consumers of the electric power, wind power and photo-electric installations (the last ones have been constructed). The paper establishes that, in order to compensate the seasonal fluctuations of power in autonomous power systems with renewable energy resources, the accumulative devices are required, with a capacity of tens of MWh including devices that are capable to provide energy storage with duration about half a year. This allows abandoning the storage devices for smoothing the seasonal fluctuations in the energy balance.The analysis of operation modes of energy stores has shown that for a stock and delivery of energy on time intervals, lasting several hours, the accumulative devices with rather high values of charging and digit power aren't required. It allows using the lead-acid rechargeable batteries of the deep category for smoothing the daily peaks of surplus and a capacity shortage. Moreover, the analysis of operation modes of energy stores as a part of the hybrid complexes has demonstrated that in charging/digit currents of the energy store the low-frequency and high-frequency pulsations of big amplitude caused by changes of size of output power of the renewable power installations and loading are inevitable. If low-frequency pulsations (the period of tens of minutes) can partially be damped due to the restriction of size of the maximum charging current of rechargeable batteries, then it is essentially impossible to eliminate high-frequency pulsations (the period of tens of seconds) in the power systems with the only store of energy. The paper finds out that the combined energy store having characteristics of the accumulator in the modes of receiving and delivery of power on daily time intervals, and at the same time having properties of the supercondenser in the modes of reception and return of impulses of power on second intervals of time is best suited to requirements of the autonomous power complexes with renewable energy resources.


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