scholarly journals Analysis of Bifurcation Behavior of a Piecewise Linear Vibrator with Electromagnetic Coupling for Energy Harvesting Applications

2014 ◽  
Vol 24 (05) ◽  
pp. 1450066 ◽  
Author(s):  
A. El Aroudi ◽  
H. Ouakad ◽  
L. Benadero ◽  
M. Younis
Keyword(s):  
Energy Harvesting ◽  
State Space ◽  
Electromagnetic Coupling ◽  
Piecewise Linear ◽  
Computing Time ◽  
Dynamical Behavior ◽  
Low Frequency ◽  
Frequency Domain Analysis ◽  
Harmonic Excitation ◽  
Low Frequencies

Recently, nonlinearities have been shown to play an important role in increasing the extracted energy of vibration-based energy harvesting systems. In this paper, we study the dynamical behavior of a piecewise linear (PWL) spring-mass-damper system for vibration-based energy harvesting applications. First, we present a continuous time single degree of freedom PWL dynamical model of the system. Different configurations of the PWL model and their corresponding state-space regions are derived. Then, from this PWL model, extensive numerical simulations are carried out by computing time-domain waveforms, state-space trajectories and frequency responses under a deterministic harmonic excitation for different sets of system parameter values. Stability analysis is performed using Floquet theory combined with Filippov method, Poincaré map modeling and finite difference method (FDM). The Floquet multipliers are calculated using these three approaches and a good concordance is obtained among them. The performance of the system in terms of the harvested energy is studied by considering both purely harmonic excitation and a noisy vibrational source. A frequency-domain analysis shows that the harvested energy could be larger at low frequencies as compared to an equivalent linear system, in particular, for relatively low excitation intensities. This could be an advantage for potential use of this system in low frequency ambient vibrational-based energy harvesting applications.

Energy harvesting from aperiodic low-frequency motion using reverse electrowetting

2017 ◽  
Vol 199 ◽  
pp. 377-392 ◽  
Author(s):  
Tsung-Hsing Hsu ◽  
J. A. Taylor ◽  
T. N. Krupenkin
Keyword(s):  
Energy Harvesting ◽  
High Power ◽  
Bubble Dynamics ◽  
Mechanical Energy ◽  
Low Frequency ◽  
Generation Process ◽  
Low Frequencies ◽  
Promising Alternative ◽  
Low Frequency Motion ◽  
Oscillation Frequencies

Mechanical energy harvesting can provide a promising alternative to electrochemical batteries, which are currently widely utilized to power mobile electronics. In this work we present a theoretical analysis of a recently proposed method of mechanical energy harvesting, which combines a reverse electrowetting phenomenon with the fast self-oscillating process of bubble growth and collapse. We investigate the details of the bubble dynamics and analyze the dependence of the energy generation process on the system parameters. The results demonstrate that self-oscillation frequencies of several kHz are possible, which can lead to very high power generation densities in excess of 104 W m−2. The obtained results indicate the possibility of high-power energy harvesting from mechanical energy sources with very low frequencies, well below 1 Hz.

scholarly journals Frequency-Domain Analysis of Atmospherically Forced versus Intrinsic Ocean Surface Kinetic Energy Variability in GFDL’s CM2-O Model Hierarchy

2018 ◽  
Vol 31 (5) ◽  
pp. 1789-1810 ◽  
Author(s):  
Amanda K. O’Rourke ◽  
Brian K. Arbic ◽  
Stephen M. Griffies
Keyword(s):  
Kinetic Energy ◽  
Frequency Domain ◽  
Spatial Scales ◽  
Low Frequency ◽  
Ocean Surface ◽  
Frequency Domain Analysis ◽  
Ocean Model ◽  
Atmospheric Forcing ◽  
Coupled Models ◽  
Low Frequencies

Low-frequency variability at the ocean surface can be excited both by atmospheric forcing, such as in exchanges of heat and momentum, and by the intrinsic nonlinear transfer of energy between mesoscale ocean eddies. Recent studies have shown that nonlinear eddy interactions can excite an energy transfer from high to low frequencies analogous to the transfer of energy from high to low wavenumbers (small to large spatial scales) in quasi-two-dimensional turbulence. As the spatial inverse cascade is driven by oceanic eddies, the process of energy exchange across frequencies may be sensitive to ocean model resolution. Here a cross-spectrum diagnostic is applied to the oceanic component in a hierarchy of fully coupled ocean–atmosphere models to address the transfer of ocean surface kinetic energy between high and low frequencies. The cross-spectral diagnostic allows for a comparison of the relative contributions of coupled atmospheric forcing through wind stress and the intrinsic advection to low-frequency ocean surface kinetic energy. Diagnostics of energy flux and transfer within the frequency domain are compared between three coupled models with ocean model horizontal resolutions of 1°, 1/4°, and 1/10° to address the importance of resolving eddies in the driving of energy to low frequencies in coupled models.

Investigation of Soft and Hard Ceramics and Single Crystals for Resonant and Off-Resonant Piezoelectric Energy Harvesting

2010 ◽  
Author(s):  
Alper Erturk ◽  
Ho-Yong Lee ◽  
Daniel J. Inman
Keyword(s):  
Power Generation ◽  
Energy Harvesting ◽  
Resonance Frequency ◽  
Single Crystals ◽  
Energy Harvester ◽  
Low Frequency ◽  
Harmonic Excitation ◽  
Resonant Excitation ◽  
Piezoelectric Energy Harvesting ◽  
Piezoelectric Energy

Piezoelectric materials have received the most attention for vibration-to-electricity conversion over the last decade. Harmonic excitation is the most commonly investigated form of excitation in piezoelectric energy harvesting and it can be divided into two subgroups as resonant and off-resonant excitations. Although resonant excitation is preferred for extracting the maximum electrical power output from the device, there are several practical cases where it is not possible to excite the energy harvester at its resonance frequency (e.g. varying frequency excitations or very low frequency excitations where the input frequency is much lower than the fundamental resonance frequency). Several researchers have used soft piezoceramics (e.g. PZT-5A and PZT-5H) for power generation under resonant excitation. Typically, these soft piezoceramics have larger piezoelectric strain constant and larger elastic compliance compared to hard piezoceramics (e.g. PZT-4 and PZT-8). However, it is known that hard piezoceramics can have an order of magnitude larger mechanical quality factor compared to soft piezoceramics. Consequently, hard piezoceramics can generate more power under resonant excitation even though researchers have mostly focused on the soft piezoceramics. On the other hand, soft piezoceramics can generate more power for low frequency excitation below the resonance frequency due to their large effective piezoelectric stress constants. This difference is also the case for soft and hard single crystals (e.g. soft PMN-PZT versus hard PMN-PZT-Mn). In addition, single crystals can generate more power than ceramics at low off-resonant frequencies due to their large dynamic flexibilities (which is related to their large elastic compliances). This work investigates the specific advantages of soft and hard piezoceramics and single crystals for vibration-based energy harvesting. An experimentally validated piezoelectric energy harvester model is used to compare the power generation performances of soft and hard ceramics as well as soft and hard single crystals. The soft and the hard piezoceramics considered in this work are PZT-5H and PZT-8, respectively, while the soft and the hard single crystals considered here are PMN-PZT and PMN-PZT-Mn, respectively.

Experimental Investigation of Energy Harvesting With Essential Nonlinearities

2011 ◽  
Author(s):  
Angela Triplett ◽  
D. Dane Quinn
Keyword(s):  
Energy Harvesting ◽  
Numerical Simulations ◽  
Electromagnetic Coupling ◽  
Average Power ◽  
Piezoelectric Element ◽  
Nonlinear Behavior ◽  
Harmonic Excitation ◽  
Linear Oscillator ◽  
Resistive Load ◽  
Sufficient Energy

The advancement of technology of portable electronics and devices has increased the need for self-sufficient energy sources. This work investigates the potentiality of a vibration-based energy harvesting system based on the response of an attachment with strong nonlinear behavior. The electromagnetic coupling is achieved by a piezoelectric element across a resistive load. Typical designs utilize a linear oscillator, which limits the peak harvesting performance to a narrow band of frequencies about the natural frequency of the oscillator. An essentially nonlinear cubic oscillator is shown, with proper design, to significantly improve the range of frequencies for sufficient harvesting when compared with a tuned linear oscillator design. Numerical simulations of the proposed model reveal this wider band of frequencies harvest significant power when the system is subjected to harmonic excitation. A physical model was developed and the acquired instantaneous voltage was recorded to calculate the average power over a resistive load and to experimentally validate the numerical simulations.

scholarly journals Experiment Investigation of Bistable Vibration Energy Harvesting with Random Wave Environment

2021 ◽  
Vol 11 (9) ◽  
pp. 3868
Author(s):  
Qiong Wu ◽  
Hairui Zhang ◽  
Jie Lian ◽  
Wei Zhao ◽  
Shijie Zhou ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Energy Harvesting ◽  
Cantilever Beam ◽  
Large Scale ◽  
Low Frequency ◽  
Vibration Energy ◽  
Random Wave ◽  
Periodic Signal ◽  
Vibration Energy Harvesting ◽  
Motion Activity

The energy harvested from the renewable energy has been attracting a great potential as a source of electricity for many years; however, several challenges still exist limiting output performance, such as the package and low frequency of the wave. Here, this paper proposed a bistable vibration system for harvesting low-frequency renewable energy, the bistable vibration model consisting of an inverted cantilever beam with a mass block at the tip in a random wave environment and also develop a vibration energy harvesting system with a piezoelectric element attached to the surface of a cantilever beam. The experiment was carried out by simulating the random wave environment using the experimental equipment. The experiment result showed a mass block’s response vibration was indeed changed from a single stable vibration to a bistable oscillation when a random wave signal and a periodic signal were co-excited. It was shown that stochastic resonance phenomena can be activated reliably using the proposed bistable motion system, and, correspondingly, large-scale bistable responses can be generated to realize effective amplitude enlargement after input signals are received. Furthermore, as an important design factor, the influence of periodic excitation signals on the large-scale bistable motion activity was carefully discussed, and a solid foundation was laid for further practical energy harvesting applications.

scholarly journals A phase-locked loop using ESO-based loop filter for grid-connected converter: performance analysis

2021 ◽  
Author(s):  
Baoling Guo ◽  
Seddik Bacha ◽  
Mazen Alamir ◽  
Julien Pouget
Keyword(s):  
Performance Analysis ◽  
Frequency Domain ◽  
Low Frequency ◽  
Experimental Tests ◽  
Frequency Measurement ◽  
Phase Locked Loop ◽  
Frequency Domain Analysis ◽  
Loop Filter ◽  
Control Stability ◽  
Unbalanced Grid

AbstractAn extended state observer (ESO)-based loop filter is designed for the phase-locked loop (PLL) involved in a disturbed grid-connected converter (GcC). This ESO-based design enhances the performances and robustness of the PLL, and, therefore, improves control performances of the disturbed GcCs. Besides, the ESO-based LF can be applied to PLLs with extra filters for abnormal grid conditions. The unbalanced grid is particularly taken into account for the performance analysis. A tuning approach based on the well-designed PI controller is discussed, which results in a fair comparison with conventional PI-type PLLs. The frequency domain properties are quantitatively analysed with respect to the control stability and the noises rejection. The frequency domain analysis and simulation results suggest that the performances of the generated ESO-based controllers are comparable to those of the PI control at low frequency, while have better ability to attenuate high-frequency measurement noises. The phase margin decreases slightly, but remains acceptable. Finally, experimental tests are conducted with a hybrid power hardware-in-the-loop benchmark, in which balanced/unbalanced cases are both explored. The obtained results prove the effectiveness of ESO-based PLLs when applied to the disturbed GcC.

scholarly journals Earless toads sense low frequencies but miss the high notes

2017 ◽  
Vol 284 (1864) ◽  
pp. 20171670 ◽  
Author(s):  
Molly C. Womack ◽  
Jakob Christensen-Dalsgaard ◽  
Luis A. Coloma ◽  
Juan C. Chaparro ◽  
Kim L. Hoke
Keyword(s):  
High Frequency ◽  
Species Differences ◽  
Low Frequency ◽  
Auditory Brainstem ◽  
Low Frequencies ◽  
Hearing Sensitivity ◽  
Sensory Pathways ◽  
Airborne Sound ◽  
Vibrational Sensitivity ◽  
Species Specific

Sensory losses or reductions are frequently attributed to relaxed selection. However, anuran species have lost tympanic middle ears many times, despite anurans' use of acoustic communication and the benefit of middle ears for hearing airborne sound. Here we determine whether pre-existing alternative sensory pathways enable anurans lacking tympanic middle ears (termed earless anurans) to hear airborne sound as well as eared species or to better sense vibrations in the environment. We used auditory brainstem recordings to compare hearing and vibrational sensitivity among 10 species (six eared, four earless) within the Neotropical true toad family (Bufonidae). We found that species lacking middle ears are less sensitive to high-frequency sounds, however, low-frequency hearing and vibrational sensitivity are equivalent between eared and earless species. Furthermore, extratympanic hearing sensitivity varies among earless species, highlighting potential species differences in extratympanic hearing mechanisms. We argue that ancestral bufonids may have sufficient extratympanic hearing and vibrational sensitivity such that earless lineages tolerated the loss of high frequency hearing sensitivity by adopting species-specific behavioural strategies to detect conspecifics, predators and prey.

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