scholarly journals A Green Triboelectric Nano-Generator Composite of Degradable Cellulose, Piezoelectric Polymers of PVDF/PA6, and Nanoparticles of BaTiO3

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 506 ◽  
Author(s):  
Zhuangzhi Sun ◽  
Lu Yang ◽  
Sicheng Liu ◽  
Jintao Zhao ◽  
Zhiwei Hu ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Output Voltage ◽  
Short Circuit ◽  
Open Circuit ◽  
Regenerated Cellulose ◽  
Cellulose Membrane ◽  
Output Current ◽  
Pure Cellulose ◽  
Circuit Output ◽  
Peak Value

In this paper, a kind of green triboelectric nano-generator based on natural degradable cellulose is proposed. Different kinds of regenerated cellulose composite layers are prepared by a blending doping method, and then assembled with poly(tetrafluoroethylene) (PTFE) thin films to form tribioelectric nanogenerator (TENG). The results show that the open circuit output voltage and the short circuit output current using a pure cellulose membrane is 7.925 V and 1.095 μA. After adding a certain amount of polyamide (PA6)/polyvinylidene fluoride (PVDF)/barium titanate (BaTiO3), the open circuit output voltage peak and the peak short circuit output current increases by 254.43% (to 20.155 V) and 548.04% (to 6.001 μA). The surface morphology, elemental composition and functional group of different cellulose layers are characterized by Scanning Electronic Microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and tested by the electrochemical analyze. Moreover, after multiple assembly and rectification processing, the electrical output performance shows that the peak value of open-circuit output voltage and the peak value of short circuit output current increases by 132.06% and 116.13%. Within 500 s of the charge-discharge test, the single peak charge reached 3.114 V, and the two peak charges reached 3.840 V. The results demonstrate that the nano-generator based on cellulose showed good stability and reliability, and the application and development of natural biomaterials represented by cellulose are greatly promoted in miniature electronic sensing area.

Fluttering Amplitude Amplification by Utilizing Flapping Moment in Flutter-Driven Triboelectric Nanogenerator

2021 ◽  
Author(s):  
Yi Zhang ◽  
Ka Chung Chan ◽  
Sau Chung Fu ◽  
Christopher Yu Hang Chao
Keyword(s):  
Flow Velocity ◽  
High Speed ◽  
Aerodynamic Force ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Energy Output ◽  
Small Scale ◽  
Triboelectric Nanogenerator ◽  
Peak Value

Abstract Flutter-driven triboelectric nanogenerator (FTENG) is one of the most promising methods to harvest small-scale wind energy. Wind causes self-fluttering motion of a flag in the FTENG to generate electricity by contact electrification. A lot of studies have been conducted to enhance the energy output by increasing the surface charge density of the flag, but only a few researches tried to increase the converting efficiency by enlarging the flapping motion. In this study, we show that by simply replacing the rigid flagpole in the FTENG with a flexible flagpole, the energy conversion efficiency is augmented and the energy output is enhanced. It is found that when the flag flutters, the flagpole also undergoes aerodynamic force. The lift force generated from the fluttering flag applies a periodic rotational moment on the flagpole, and causes the flagpole to vibrate. The vibration of the flagpole, in turn amplifies the flutter of the flag. Both the fluttering dynamics of the flags with rigid and flexible flagpoles have been recorded by a high-speed camera. When the flag was held by a flexible flagpole, the fluttering amplitude and the contact area between the flag and electrode plates were increased. The energy enhancement increased as the flow velocity increased and the enhancement can be 113 times when the wind velocity is 10 m/s. The thickness of the flagpole was investigated. An optimal output of open-circuit voltage reaching 1128 V (peak-to-peak value) or 312.40 V (RMS value), and short-circuit current reaching 127.67 μA (peak-to-peak value) or 31.99 μA (RMS value) at 12.21 m/s flow velocity was achieved. This research presents a simple design to enhance the output performance of an FTENG by amplifying the fluttering amplitude. Based on the performance obtained in this study, the improved FTENG has the potential to apply in a smart city for driving electronic devices as a power source for IoT applications.

Improved Piezoelectric Performance of Electrospun PVDF Nanofibers with Conductive Paint Coated Electrode

2019 ◽  
Vol 19 (02) ◽  
pp. 1950008 ◽  
Author(s):  
R. Tamil Selvan ◽  
W. A. D. M. Jayathilaka ◽  
A. Hilaal ◽  
S. Ramakrishna
Keyword(s):  
Contact Area ◽  
Electrode Material ◽  
Polyvinylidene Fluoride ◽  
Electrode Materials ◽  
Low Cost ◽  
Short Circuit ◽  
Open Circuit ◽  
Energy Output ◽  
Piezoelectric Performance ◽  
Conductive Paint

Fabrication of Nanogenerators (NGs) using Electrospun polyvinylidene fluoride (PVDF) nanofibers for sensing and energy harvesting applications is a trending research due to its flexibility, biocompatibility, low-cost, etc. Different electrode materials, polymer composites had been proposed to increase the energy output. However, the contact area between the electrode material and nanofiber mat which helps to conduct more piezoelectric charges to the electrode surface are still unexplored especially at nanoscale level. In this paper, authors have proposed the use of low-cost carbon conductive paint to increase the contact area between the electrode and nanofiber mat. The electrode material is coated with conductive paint and the NG was fabricated with that electrode to compare the performances with conventional NG. Piezoelectric performance of the proposed NG has increased substantially as it generates an open circuit voltage [Formula: see text]) of 4.5[Formula: see text]V and short circuit current [Formula: see text]) of 25[Formula: see text]nA, whereas the conventional NG can only produce 1.6 [Formula: see text]) and 1.5[Formula: see text]nA [Formula: see text]). A drop test experiment was conducted, and the device consistency was verified experimentally.

scholarly journals Current-pumping performance of axial-symmetric superconducting dynamo designs

2021 ◽  
Author(s):  
◽  
Sin Hoi Phang
Keyword(s):  
Liquid Nitrogen ◽  
Output Voltage ◽  
Short Circuit ◽  
Local Heating ◽  
Open Circuit ◽  
Experimental Results ◽  
Operating Frequency ◽  
Design Parameters ◽  
Dynamic Resistance ◽  
Frequency Regime

<p>In this project, the current pumping performances of three high temperature superconducting (HTS) dynamos (mechanically-rotating flux pumps) were investigated. These flux pumps (FPs) were identified as the Gen 1, Gen 2 and Gen 4 FP respectively. They were modelled using simple DC equivalent circuits and their performances were defined by three output parameters: DC open-circuit voltage (Voc), dynamic resistance (Rd) and DC short-circuit current (Isc). The experimental results showed that these FPs produced non-zero DC output voltages across their stators and each supplied DC output currents into series connected superconducting circuits.  The Gen 1 FP was cooled with liquid nitrogen and operated at 77 K. The stators were made from 12-mm wide copper-coated yttrium barium copper oxide (YBCO) HTS conductors. The objective of the experiment was to investigate the effect of the rotor magnet size, geometry and orientation (with respect to the stators) on the FP performance. The design parameters, based on the width and the length of the magnet with respect to the stator, for optimal FP performance were determined.  The Gen 2 FP was also cooled with liquid nitrogen and operated at 77 K. The stators were made from 46-mm wide Ag-coated YBCO HTS conductors. The objective of the experiment was to investigate the effect of stator width on the FP performance at various magnet frequencies. This was done by slitting two of the stators to form parallel stators with equal width, but smaller than the original conductor width. The experimental results showed that the FP performance was highly dependent on the operating frequency. Three operating frequency regimes were observed: low, mid and high. At high frequency, the Voc decreased and the Rd increased signifcantly. This was attributed to the local heating effect in the stator due to the increase in the current density. As a result, the FP produced zero output current in this regime. The AC voltage waveforms measured across the stators in different frequency regimes were very different in shapes and amplitudes. Therefore, these waveforms can be used to identify the operating frequency regime of the FP. At some operating frequencies in the mid frequency regime, bi-stable operating modes were observed, each mode resulted in different output parameters.  The Gen 4 FP was constructed in this project. It was cooled via thermal conduction method using a cryorefrigerator system. It had an axial-symmetric stator design where the shape of the stator is cylindrical. The width of the stator was considerably larger compared with the Gen 1 and Gen 2 FPs. The experiment objective was to investigate whether this design would produce a DC current, and then characterise the FP performance at different operating temperatures. The experimental results showed that the time-averaged DC output voltage of the Gen 4 FP was much higher compared with the Gen 1 and Gen 2 FPs. The reason is that it produced a DC output voltage for almost the entire rotor cycle. The experimental results also indicated that the Gen 4 FP has the capability to produce output currents in the kA range.</p>

Modeling the open circuit output voltage of piezoelectric nanogenerator

2013 ◽  
Vol 56 (11) ◽  
pp. 2622-2629 ◽  
Author(s):  
Xin Huang ◽  
LiJie Li ◽  
Yan Zhang
Keyword(s):  
Output Voltage ◽  
Open Circuit ◽  
Circuit Output

Preparation, Characterization and Biocompatibility of Regenerated Cellulose/PVA Blend Membranes in 1-Allyl-3-Methyimidazolium Chloride

2011 ◽  
Vol 179-180 ◽  
pp. 1108-1111 ◽  
Author(s):  
Yun Lu ◽  
Yi Xing Liu ◽  
Hai Peng Yu ◽  
Qing Feng Sun
Keyword(s):  
Ionic Liquid ◽  
Phase Separation ◽  
Polyvinyl Alcohol ◽  
Regenerated Cellulose ◽  
Cellulose Membrane ◽  
Sem Images ◽  
Pure Cellulose ◽  
Blend Membranes

Regenerated cellulose/polyvinyl alcohol (PVA) blend membranes were prepared from a solution of cellulose and PVA in an ionic liquid of 1-allyl-3-methyimidazolium chloride (AMImCl). SEM images showed that the phase separation on the mixture was severely formed when the content of PVA was higher than 10% by volume. However, when the content of PVA in the mixture was lower than 6%, the cellulose and PVA were well-distributed. The regenerated blend membranes using the AMImCl presenting reasonable crystallinity were superior to those of regenerated pure cellulose membrane. In conclusion, the compatible properties of blend membranes from regenerated cellulose/PVA (6%) were improved and the blend membranes kept original biodegradability.

scholarly journals Current-pumping performance of axial-symmetric superconducting dynamo designs

2021 ◽  
Author(s):  
◽  
Sin Hoi Phang
Keyword(s):  
Liquid Nitrogen ◽  
Output Voltage ◽  
Short Circuit ◽  
Local Heating ◽  
Open Circuit ◽  
Experimental Results ◽  
Operating Frequency ◽  
Design Parameters ◽  
Dynamic Resistance ◽  
Frequency Regime

<p>In this project, the current pumping performances of three high temperature superconducting (HTS) dynamos (mechanically-rotating flux pumps) were investigated. These flux pumps (FPs) were identified as the Gen 1, Gen 2 and Gen 4 FP respectively. They were modelled using simple DC equivalent circuits and their performances were defined by three output parameters: DC open-circuit voltage (Voc), dynamic resistance (Rd) and DC short-circuit current (Isc). The experimental results showed that these FPs produced non-zero DC output voltages across their stators and each supplied DC output currents into series connected superconducting circuits.  The Gen 1 FP was cooled with liquid nitrogen and operated at 77 K. The stators were made from 12-mm wide copper-coated yttrium barium copper oxide (YBCO) HTS conductors. The objective of the experiment was to investigate the effect of the rotor magnet size, geometry and orientation (with respect to the stators) on the FP performance. The design parameters, based on the width and the length of the magnet with respect to the stator, for optimal FP performance were determined.  The Gen 2 FP was also cooled with liquid nitrogen and operated at 77 K. The stators were made from 46-mm wide Ag-coated YBCO HTS conductors. The objective of the experiment was to investigate the effect of stator width on the FP performance at various magnet frequencies. This was done by slitting two of the stators to form parallel stators with equal width, but smaller than the original conductor width. The experimental results showed that the FP performance was highly dependent on the operating frequency. Three operating frequency regimes were observed: low, mid and high. At high frequency, the Voc decreased and the Rd increased signifcantly. This was attributed to the local heating effect in the stator due to the increase in the current density. As a result, the FP produced zero output current in this regime. The AC voltage waveforms measured across the stators in different frequency regimes were very different in shapes and amplitudes. Therefore, these waveforms can be used to identify the operating frequency regime of the FP. At some operating frequencies in the mid frequency regime, bi-stable operating modes were observed, each mode resulted in different output parameters.  The Gen 4 FP was constructed in this project. It was cooled via thermal conduction method using a cryorefrigerator system. It had an axial-symmetric stator design where the shape of the stator is cylindrical. The width of the stator was considerably larger compared with the Gen 1 and Gen 2 FPs. The experiment objective was to investigate whether this design would produce a DC current, and then characterise the FP performance at different operating temperatures. The experimental results showed that the time-averaged DC output voltage of the Gen 4 FP was much higher compared with the Gen 1 and Gen 2 FPs. The reason is that it produced a DC output voltage for almost the entire rotor cycle. The experimental results also indicated that the Gen 4 FP has the capability to produce output currents in the kA range.</p>

scholarly journals A Pendulum-Like Low Frequency Electromagnetic Vibration Energy Harvester Based on Polymer Spring and Coils

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3380
Author(s):  
Yunjia Li ◽  
Xinyi Wang ◽  
Shuhan Zhang ◽  
Chenyuan Zhou ◽  
Dayong Qiao ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Output Voltage ◽  
Degrees Of Freedom ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Low Frequency ◽  
Open Circuit ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Circuit Output

This paper presents a low-frequency electromagnetic vibrational energy harvester (EVEH) with two degrees of freedom and two resonant modes. The proposed EVEH is based on a disc magnet suspended in a pendulum fashion by a polymeric spring between two sets of polymer coil stacks. The fabricated EVEH is capable of harvesting vibration energy on two directions with an extended bandwidth. With a sinusoidal acceleration of ±1 g on Z direction, a peak-to-peak closed-circuit output voltage of 0.51 V (open-circuit voltage: 1 V), and an output power of 35.1 μW are achieved at the resonant frequency of 16 Hz. With a sinusoidal acceleration of ±1.5 g on X direction, a peak-to-peak output voltage of 0.14 V and power of 2.56 μW are achieved, at the resonant frequency of 20 Hz.

Study on Varying-Step Commutation Strategy of Matrix Converter

2011 ◽  
Vol 143-144 ◽  
pp. 132-138
Author(s):  
Xing He Ma ◽  
Jun Ying Zhao ◽  
Li Jia ◽  
Peng Fei Ji
Keyword(s):  
Short Circuit ◽  
Input Voltage ◽  
Open Circuit ◽  
Matrix Converter ◽  
Current Direction ◽  
Output Current ◽  
Output Waveform ◽  
New Strategy

Aiming at safe commutation and improving quality of output waveform, the paper presents a new varying-step safe commutation strategy of matrix converter by analyzing the character of traditional four-step commutation and improved four-step commutation strategy. On the basis of input-voltage-based commutation this new strategy synthetically considers the magnitude of input voltage and output current direction and accordingly distinguishes the safe partition and the unsafe partition. Then different commutation strategies are adopted in different partition which improving the reliability of commutation and decreasing the commutation time to improve the quality of output waveform. Finally, the( ) experiment results demonstrate the availability and reliability of the presented commutation strategy. Thereby, the open-circuit or short-circuit faulty caused by abnormal commutation can be eliminated. The output waveform can be improved because the commutation time can be decreased by 2/3 compared to the traditional four-step commutation strategy.

Using Only the DC Current Information to Detect Stator Turn Faults in Automotive Claw-Pole Generators

2013 ◽  
Vol 60 (8) ◽  
pp. 3462-3471 ◽  
Author(s):  
Siwei Cheng ◽  
Thomas Habetler
Keyword(s):  
Output Voltage ◽  
Short Circuit ◽  
Electric Power System ◽  
Detection Methods ◽  
Output Current ◽  
Bridge Rectifier ◽  
Ac Current ◽  
Sensor Information ◽  
Dc Current ◽  
Generator Output

The stator turn-to-turn short circuit is an important type of fault in automotive claw-pole generators. In a typical vehicle electric power system, the built-in rectifier of the generator makes it difficult to access the ac current or voltage information, rendering conventional sequence-component-based fault-detection methods useless. To detect such fault using only the available sensor information, a dynamic model of the claw-pole generator with stator turn faults is derived in this paper to analyze how the fault would interact with the connected battery and the static full-bridge rectifier and how it would affect the generator's output voltage and current. It is found that, in the rectified generator output current, the harmonic at one-third of the rectifier ripple frequency is a robust signature of the stator turn fault. The performance of the stator turn-fault detector is demonstrated by extensive experimental results. Although the fault detector is originally proposed for claw-pole generators, it is also applicable to most polyphase ac generators with a dc-link rectifier.

scholarly journals A study on performances of carrier-based pulse-width modulation techniques for three-phase three-level t-type neutral-point-clamped inverter under switch-open-circuit fault on two neutral-point-connected legs

2020 ◽  
Vol 3 (3) ◽  
pp. first
Author(s):  
Nhờ Văn NGUYỄN ◽  
HONG-PHONG NGUYEN LE
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Short Circuit ◽  
Harmonic Distortion ◽  
Open Circuit ◽  
Neutral Point ◽  
Voltage Source ◽  
Voltage Source Inverters ◽  
Critical Issues

Multilevel voltage source inverters (VSIs) have been used for several decades thanks to their advantages compared with traditional two level VSI. Among various types of multilevel configuration, the T-type neutral-point-clamped VSI (3L TNPC VSI or 333-type VSI) has gained the attention in recent years. Due to the unique structure, the 333-type VSI has critical issues in reliability in operation such as switch-open-circuit (SOC) and switch-short-circuit (SSC), which lead to several unrequired issues, for instance, reduction of system performance, distorted and unbalanced output voltages and currents, or triggering the protection circuits. In some applications, the amplitude reduction and harmonics distortion of output voltages in SOC faults are not acceptable. Therefore, it is necessary to develop a pulse-width modulation (PWM) algorithm for 333-type VSI working under SOC fault which guarantees the desired output fundamental component voltage. The simultaneous SOC fault on two neutral-point-connected legs in the 333-type VSI may cause a large reduction in the output voltage. Under this circumstance, the 333-type VSI becomes an asymmetrical one called 322-type VSI. Certain studies regarding to the operation of 333-type VSI under SOC faults have been carried out. However, these studies require more semiconductor devices in order to create a redundant switching circuit. This leads to higher system cost with reduced inverter effieciency due to the additional loss. In this study, two carrier-based pulse-width modulation (CBPWM) techniques, i.e. 322-sinusoidal PWM (322-SPWM) and 322-medium offset CBPWM (322-MOCBPWM) are proposed for 322-type VSI. The proposed techniques are firstly simulated in MATLAB/Simulink and then implemented on a hardware setup. Performances of the proposed techniques are evaluated in terms of total harmonic distortion (THD) and weighted-THD (WTHD) of output voltages. Simulation results show that considering the worst output voltage under SOC fault, vBC, the proposed 322-SPWM technique could improve the THD by 40% and the WTHD by 94% compared with the uncompensated case with m=0.8. The corresponding results of 322-MOCBPWM technique are 42% and 96%, respectively. Characteristics of THD and WTHD values are also presented for demonstration the effectiveness of the proposed algorithm.

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