Hybrid Piezo/Magnetic Electromechanical Transformer

This paper presents a hybrid electromechanical transformer that passively transfers electrical power between galvanically isolated ports by coupling electrodynamic and piezoelectric transducers. The use of these two complementary electromechanical transduction methods along with a high-Q mechanical resonance affords very large transformations of voltage, current, or impedance at particular electrical frequencies. A chip-size prototype is designed, simulated, fabricated, and experimentally characterized. The 7.6 mm 7.6 mm 1.65 mm device achieves an open-circuit voltage gain of 31.4 and 48.7 when operating as a step-up transformer at 729.5 Hz and 1015 Hz resonance frequencies, respectively. When operating as a step-down transformer, the resonance frequencies and the corresponding voltage gains are 728 Hz, 1002 Hz, and 0.0097, 0.0128, respectively. In one operational mode, the system shows a minimum power dissipation of only 0.9 µW corresponding to a power conversion efficiency of 11.8%.

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Optimization of Method and Components of Enzymatic Fuel Cells

Journal of the Nigerian Society of Physical Sciences ◽

10.46481/jnsps.2019.17 ◽

2019 ◽

pp. 143-146

Author(s):

Ibukun Akinsola ◽

Aderemi Babatunde Alabi ◽

Muibat A Soliu ◽

Taiye Akomolafe

Keyword(s):

Fuel Cells ◽

Open Circuit Voltage ◽

Short Circuit ◽

Renewable Energy Sources ◽

Electrical Power ◽

Short Circuit Current ◽

Electrical Energy ◽

Open Circuit ◽

Biofuel Cell ◽

Carbon Electrodes

Enzymatic fuel cells produce electrical power by oxidation of renewable energy sources. An enzymatic glucose biofuel cell uses glucose as fuel and enzymes as biocatalyst, to convert biochemical energy into electrical energy. The applications which need low electrical voltages and low currents have much of the interest in developing enzymatic fuel cells. The cell was constructed using three different materials with different electrodes (Bitter leaf and Copper electrodes (BCu), Bitter leaf and Carbon electrodes (BC) and Water leaf and Carbon electrodes (WC)). The short circuit current and open circuit voltage were measured in micro-ampere (mu A) and milli-volt (mV) respectively at 30 minutes interval over the period of 12 hours (from dawn to dusk). The results which show that fuel cells constructed using bitter leaf with carbon electrode has the highest open circuit voltage, short circuit current and generated power of 162.8~mV, 1.65~ mu A and 268.62~nW respectively at 720~mins is obtained from the plots generated by the use of Microsoft Excel. The results show that all short circuit currents, voltages and powers generated increases with time and this is as a result of the exposure to solar radiation during the period of taking the measurement.

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Early fever detection on COVID-19 infection using thermoelectric module generators

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v11i5.pp3828-3837 ◽

2021 ◽

Vol 11 (5) ◽

pp. 3828

Author(s):

Daniel Sanin-Villa ◽

Oscar D. Monsalve-Cifuentes ◽

Jorge Sierra Del Rio

Keyword(s):

Thermoelectric Generator ◽

Open Circuit Voltage ◽

Numerical Study ◽

Electrical Power ◽

Thermoelectric Module ◽

Open Circuit ◽

Human Interaction ◽

Hexahedral Mesh ◽

Maximum Value ◽

P Type

In 2020 the COVID-19 pandemic has suddenly stopped society and changed human interaction. In this work, a thermoelectric generator wearable device for early fever detection symptoms is presented as a possible solution to avoid higher propagation of this disease. To identify a possible fever symptom, numerical and parametric simulations are developed using a highquality-refined hexahedral mesh. At first, a 2-pair-leg thermoelectric module has undergone simulations to establish temperature conditions, open-circuit voltage, and power output generation; and secondly, these previous results are extrapolated for a larger thermoelectric module containing 28 pair-leg of N-P type material. The numerical study shows that a maximum value of electrical power of 60.70 mW was reached for 28-pair-leg N-P type thermocouples under a constant temperature difference of 20 K.

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Temperature-Dependent Analysis of Solid-State Photon-Enhanced Thermionic Emission Solar Energy Converter

Energies ◽

10.3390/en13071554 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1554

Author(s):

Yang Yang ◽

Wei Wei Cao ◽

Peng Xu ◽

Bing Li Zhu ◽

Yong Lin Bai ◽

...

Keyword(s):

Solid State ◽

Solar Energy ◽

High Temperatures ◽

Open Circuit Voltage ◽

Elevated Temperatures ◽

Electrical Power ◽

Thermionic Emission ◽

Open Circuit ◽

Temperature Dependent ◽

Doping Density

Solid-state photon-enhanced thermionic emission (PETE) solar energy converters are newly proposed devices that can directly convert solar energy into electrical power at high temperatures. An analytical model based on a one-dimensional steady-state equation is developed to analyze the temperature-dependent performance of the solid-state PETE converter. The treatment used to derive the reverse saturation current density ( J 0 ) and open-circuit voltage ( V o c ) of the solid-state PETE converter is similar to that used in photovoltaic cells. Thus, their performances at elevated temperatures can be compared. Analysis results show that J 0 of the solid-state PETE converter with a GaAs absorption layer is approximately three orders of magnitude lower, and the decrease rate of open-circuit voltage ( − d V o c / d T ) is smaller than that of a practical GaAs photovoltaic cell. The improved performance of the solid-state PETE converter at high temperatures is attributed to the simultaneous use of diffusion and ballistic transport to harvest photo-generated electrons. The results presented in this paper demonstrate that, besides using wide bandgap materials and increasing doping density, harvesting solar energy via PETE effect can effectively improve the performance of solar cells at elevated temperatures.

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Nanostructure Control of Si and Ge Quantum Dots Based Solar Cells Using Plasma Processes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.2022 ◽

2014 ◽

Vol 783-786 ◽

pp. 2022-2027 ◽

Cited By ~ 1

Author(s):

Masaharu Shiratani ◽

Giichiro Uchida ◽

Hyun Woong Seo ◽

Daiki Ichida ◽

Kazunori Koga ◽

...

Keyword(s):

Solar Cells ◽

Fill Factor ◽

Open Circuit Voltage ◽

Short Circuit ◽

Electrical Power ◽

Chemical Vapor ◽

Short Circuit Current ◽

Open Circuit ◽

Si Nanoparticles ◽

Sensitized Solar Cells

We report characteristics of quantum dot (QD) sensitized solar cells using Si nanoparticles and Ge nanoparticles. Si nanoparticles were synthesized by multi-hollow discharge plasma chemical vapor deposition, whereas Ge nanoparticles were done by a radio frequency magnetron sputtering using Ar+H2under high pressure conditions. The electrical power generation from Si QDs and Ge QDs was confirmed. Si QD sensitized solar cells show an efficiency of 0.024%, fill factor of 0.32, short-circuit current of 0.75 mA/cm2and open-circuit voltage of 0.10 V, while Ge QD sensitized solar cells show an efficiency of 0.036%, fill factor of 0.38, short-circuit current of 0.64 mA/cm2and open-circuit voltage of 0.15 V.

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Development of an Automated Biaxial Solar Photovoltaic Tracking System

Scientific Research Journal ◽

10.24191/srj.v3i2.5666 ◽

2006 ◽

Vol 3 (2) ◽

pp. 1

Author(s):

Ahmad Maliki Omar ◽

Muhamad Rizuan Yahir ◽

Sulaiman Shaari ◽

Abdul Rahman Omar

Keyword(s):

Power Output ◽

Solar Irradiance ◽

Open Circuit Voltage ◽

Tracking System ◽

Electrical Power ◽

Open Circuit ◽

Maximum Output ◽

Solar Photovoltaic ◽

Pv System ◽

Solar Altitude

This paper presents and describes a prototype product code-named SolT2A which is a system that tracks the position of the sun automatically across the celestial vault in two axes. This kind of system is typically used in a solar photovoltaic (PV) system in terrestrial applications to provide electrical power. It is designed and fabricated due to Malaysia’s location near the equator, thus the solar altitude crosses the zenith and the azimuth reverses direction during the year. Thus the use of a static PV system is not maximised during half of the year. This situation can be addressed by using a two-axes solar tracking system. So far, Malaysia has not implemented such power-tracking systems. Thus SolT2A has been designed and fabricated to address the problem by using a combination of electro-mechanical devices with an element of programming ingenuity and intelligence. Basically SolT2A measures solar irradiance at four points and makes comparisons in terms of the intensity received. These data are then analysed and processed by a controller before being sent to a DC motor that ensures the maximum amount of solar irradiance received on the PV panels all the time. Thus SolT2A is a system that maximises the power output of the PV panels to obtain the highest power output continuously. Based on field data, the maximum output open circuit voltage produced by the SolT2A tracking system and that with a static PV system is as much as 82 %. The overall increase in open circuit voltage production is between 15 to 20 % daily. With the technical know-how and proven prototype, Malaysia can look into joining the small and limited but niche pool of expertise in this area. This will not only give immediate socio-economic impact to the population, but will give an upgrade to Malaysia as a country with expertise in the area. This concept could also be applied to defence systems. With further testing and improvement, SolT2A system can be further upgraded to reach a commercial stage. This will definitely be of commercial interest to the country.

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Microcrystalline (Si,Ge):H Solar Cells

MRS Proceedings ◽

10.1557/proc-762-a7.6 ◽

2003 ◽

Vol 762 ◽

Cited By ~ 1

Author(s):

Jianhua Zhu ◽

Vikram L. Dalal

Keyword(s):

Solar Cells ◽

Buffer Layer ◽

Quantum Efficiency ◽

Fill Factor ◽

Open Circuit Voltage ◽

Defect Density ◽

Cell Structure ◽

Open Circuit ◽

Base Layer ◽

Ecr Plasma

AbstractWe report on the growth and properties of microcrystalline Si:H and (Si,Ge):H solar cells on stainless steel substrates. The solar cells were grown using a remote, low pressure ECR plasma system. In order to crystallize (Si,Ge), much higher hydrogen dilution (∼40:1) had to be used compared to the case for mc-Si:H, where a dilution of 10:1 was adequate for crystallization. The solar cell structure was of the p+nn+ type, with light entering the p+ layer. It was found that it was advantageous to use a thin a-Si:H buffer layer at the back of the cells in order to reduce shunt density and improve the performance of the cells. A graded gap buffer layer was used at the p+n interface so as to improve the open-circuit voltage and fill factor. The open circuit voltage and fill factor decreased as the Ge content increased. Quantum efficiency measurements indicated that the device was indeed microcrystalline and followed the absorption characteristics of crystalline ( Si,Ge). As the Ge content increased, quantum efficiency in the infrared increased. X-ray measurements of films indicated grain sizes of ∼ 10nm. EDAX measurements were used to measure the Ge content in the films and devices. Capacitance measurements at low frequencies ( ~100 Hz and 1 kHz) indicated that the base layer was indeed behaving as a crystalline material, with classical C(V) curves. The defect density varied between 1x1016 to 2x1017/cm3, with higher defects indicated as the Ge concentration increased.

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