scholarly journals Impact of flux gap upon dynamic resistance of a rotating HTS flux pump

2021 ◽  
Author(s):  
Zhenan Jiang ◽  
Christopher Bumby ◽  
Rodney Badcock ◽  
HJ Sung ◽  
Nicholas Long ◽  
...  
Keyword(s):  
Open Circuit Voltage ◽  
Internal Resistance ◽  
Open Circuit ◽  
Dynamic Resistance ◽  
Coated Conductor ◽  
Simple Circuit ◽  
Output Performance ◽  
Magnet Coil ◽  
Good Agreement ◽  
Flux Pump

HTS flux pumps enable superconducting currents to be directly injected into a magnet coil without the requirement for thermally inefficient current leads. Here, we present results from an experimental mechanically rotating HTS flux pump employing a coated-conductor stator and operated at 77 K. We show the effect of varying the size of the flux gap between the rotor magnets and coated conductor stator from 1 to 7.5 mm. This leads to a corresponding change in the peak applied perpendicular magnetic field at the stator from approximately 350 to 50 mT. We observe that our experimental device ceases to maintain a measurable output at flux gaps above 7.5 mm, which we attribute to the presence of screening currents in the stator wire. We show that our mechanically rotating flux pump is well described by a simple circuit model which enables the output performance to be described using two simple parameters, the open-circuit voltage Voc and the internal resistance, Rd. Both of these parameters are found to be directly proportional to magnet-crossing frequency and decrease with increasing flux gap. We show that the trend in Rd can be understood by considering the dynamic resistance experienced at the stator due to the oscillating amplitude of the applied rotor field. We adopt a literature model for the dynamic resistance within our coated-conductor stator and show that this gives good agreement with the experimentally measured internal resistance of our flux pump. This is the Accepted Manuscript version of an article accepted for publication in 'Superconductor Science and Technology". IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/0953-2048/28/11/115008.

scholarly journals Impact of flux gap upon dynamic resistance of a rotating HTS flux pump

2021 ◽  
Author(s):  
Zhenan Jiang ◽  
Christopher Bumby ◽  
Rodney Badcock ◽  
HJ Sung ◽  
Nicholas Long ◽  
...  
Keyword(s):  
Open Circuit Voltage ◽  
Internal Resistance ◽  
Open Circuit ◽  
Dynamic Resistance ◽  
Coated Conductor ◽  
Simple Circuit ◽  
Output Performance ◽  
Magnet Coil ◽  
Good Agreement ◽  
Flux Pump

HTS flux pumps enable superconducting currents to be directly injected into a magnet coil without the requirement for thermally inefficient current leads. Here, we present results from an experimental mechanically rotating HTS flux pump employing a coated-conductor stator and operated at 77 K. We show the effect of varying the size of the flux gap between the rotor magnets and coated conductor stator from 1 to 7.5 mm. This leads to a corresponding change in the peak applied perpendicular magnetic field at the stator from approximately 350 to 50 mT. We observe that our experimental device ceases to maintain a measurable output at flux gaps above 7.5 mm, which we attribute to the presence of screening currents in the stator wire. We show that our mechanically rotating flux pump is well described by a simple circuit model which enables the output performance to be described using two simple parameters, the open-circuit voltage Voc and the internal resistance, Rd. Both of these parameters are found to be directly proportional to magnet-crossing frequency and decrease with increasing flux gap. We show that the trend in Rd can be understood by considering the dynamic resistance experienced at the stator due to the oscillating amplitude of the applied rotor field. We adopt a literature model for the dynamic resistance within our coated-conductor stator and show that this gives good agreement with the experimentally measured internal resistance of our flux pump. This is the Accepted Manuscript version of an article accepted for publication in 'Superconductor Science and Technology". IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/0953-2048/28/11/115008.

scholarly journals Plane Wave Coupling to a Transmission Line Above Ground with Terminating Loads

2019 ◽  
Vol 8 (1) ◽  
pp. 82-90
Author(s):  
L. K. Warne ◽  
S. Campione ◽  
R. S. Coats
Keyword(s):  
Plane Wave ◽  
Transmission Line ◽  
Radiation Effects ◽  
Short Circuit ◽  
Open Circuit ◽  
Simple Circuit ◽  
Transmission Line Model ◽  
Wave Coupling ◽  
Full Wave ◽  
Good Agreement

This paper considers plane wave coupling to a transmission line consisting of an aerial wire above a conducting ground. Simple circuit models are constructed for the terminating impedances at the ends of the line including radiation effects. We consider the following load topologies: open circuit, short circuit, and grounded rods. Results from the transmission line model with these loads show good agreement with full-wave simulations.  

Estimating the Internal Resistance of Li-Ion Battery with Joule's Law to find the Open Circuit Voltage

2021 ◽  
Author(s):  
Venkata Nagarjun PM ◽  
Hirshik Ram S ◽  
Pratik Uthan ◽  
Veeramani V ◽  
Senthilkumar Subramaniam
Keyword(s):  
Open Circuit Voltage ◽  
Internal Resistance ◽  
Open Circuit ◽  
Li Ion Battery ◽  
Li Ion

Thermoelectric Modules For High Temperature Waste Heat

2005 ◽  
Vol 886 ◽  
Author(s):  
Ryoji Funahashi ◽  
Toshiyuki Mihara ◽  
Masashi Mikami ◽  
Saori Urata
Keyword(s):  
Room Temperature ◽  
Open Circuit Voltage ◽  
Waste Heat ◽  
Thermal Strain ◽  
Thermoelectric Module ◽  
Internal Resistance ◽  
Open Circuit ◽  
Cold Side ◽  
Adhesive Material ◽  
Thermoelectric Modules

ABSTRACTA new adhesive material has been developed in order to obtain practically usable thermoelectric modules composed of oxide thermoelectric legs. The thermoelectric module composed of 8-pair oxide legs has been fabricated. Both hot- and cold-sides of the module were covered by alumina plates. Open circuit voltage VO and maximum power Pmax reach 0.38 V and 0.30 W, respectively at 803 K of a hot-side temperature TH and 362 K of a temperature differential ΔT between TH and cold-side temperature TC. Generating power was repeated 11 times at 873-993 K of TH and at 200-290 K of ΔT. The module was cooled down to room temperature after each generation. At third measurement internal resistance RI of the module increased by 30 %. This is due to destruction of junctions because of thermal strain. No deterioration, however, was observed in thermoelectric properties for the oxide legs.

scholarly journals Expression de la Tension Photovoltaïque Induite par Transition Interbande Dans des Couches Minces de Sulfure de Zinc

1975 ◽  
Vol 2 (2) ◽  
pp. 147-155 ◽  
Author(s):  
A. Tosser ◽  
H. Murray
Keyword(s):  
Experimental Data ◽  
Conduction Band ◽  
Photon Energy ◽  
Open Circuit Voltage ◽  
Sandwich Structures ◽  
Interband Transition ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Good Agreement

En considérant les variations dimensionnelles de la tension photovoltaïque induite en circuit ouvert par des rayonnements lumineux d'énergie supérieure à 3,66 eV dans des structures sandwich Al/ZnS/Au, ainsi que les variations avec le flux lumineux du courant de court-circuit et de la conductance correspondant à la phototransition entre bandes, l'hypothèse d'une quasi-bande de conduction créée par l'ionisation de centres coulombiens est avancée. Elle conduit à une formulation de la tension photovoltaïque en bonne cohérence avec l'expérience.Variations with thickness of open-circuit voltage, short-circuit current and photoconductance associated to interband transition lead to postulate the existence of a quasi-conduction band, associated with ionized coulombic centres, in Al/ZnS/Au illuminated (photon energy > 3,66 eV) sandwich structures. An expression of open-circuit voltage is deduced, in good agreement with experimental data.

scholarly journals A spontaneously sustainable bioinspired interfacial evaporation driven power generation strategy

2021 ◽  
Author(s):  
Zhuangzhi Sun ◽  
Zhaoxin Li ◽  
Changlong Han ◽  
Mingxing Jing ◽  
Haipeng Yu ◽  
...  
Keyword(s):  
Power Generation ◽  
Open Circuit Voltage ◽  
Unit Area ◽  
Light Trapping ◽  
Coulomb Field ◽  
Open Circuit ◽  
Low Grade ◽  
Average Value ◽  
Output Performance ◽  
Liquid Evaporation

Abstract In nature, liquid evaporation occurs everywhere all the time. This low-grade energy absorption to drive liquid evaporation is greatly potential for sustainable spontaneously power generation. Here, a natural liquid evaporation strategy of interfacial evaporation driven nanogenerator (IENG) is developed in this work. Coupled by the phonon wind and a fluctuating Coulomb field, an induced direct current is generated. Simultaneously, inspired by the light-trapping properties of moth eye, a simple and efficient BLT-IENG including a hierarchical surface of bionic light-trapping and electrospinning perovskite conductivity with an enhanced thermally insulating and water storage capability is designed. This enhancement of the output performance is greatly attributed to the improvement of the interfacial evaporation characteristics driven by natural solar and wind energies. Hence, our BLT-IENG achieves a breakthrough in the unit area open-circuit voltage in the marine environment, which is improved by a factor of 7.6 over the currently reported average value. This work provides an unexplored strategy for multi-energies inspired natural interfacial evaporation driven power generation.

EXPERIMENTAL INVESTIGATION ON CHARACTERISTICS OF LOW-CONCENTRATING SOLAR CELLS

2011 ◽  
Vol 25 (09) ◽  
pp. 679-684 ◽  
Author(s):  
W. B. XIAO ◽  
X. D. HE ◽  
J. T. LIU ◽  
Y. Q. GAO
Keyword(s):  
Solar Cells ◽  
Light Intensity ◽  
Open Circuit Voltage ◽  
Short Circuit ◽  
Incident Light ◽  
Short Circuit Current ◽  
Light Level ◽  
Spot Size ◽  
Internal Resistance ◽  
Open Circuit

At room temperature, the performance of low-concentrating solar cells is investigated experimentally and discussed by theory. The results show that the short-circuit current, which is larger than that of unconcentrated radiation, linearly increases with the light intensity and is directly proportional to the concentration ratio. However, the different behavior is obtained for the open-circuit voltage. The open-circuit voltage is also larger than that at the unconcentrated light level and follows a logarithmic function of the light intensity, showing almost no dependence on the concentration ratios. The main reason is the decrease in internal resistance of solar cell with decreasing spot size, because the increase of incident light intensity leads to an increase of current density. Therefore, an advantage of the low-concentrating photovoltaic systems results from the improvement of the short-circuit current, but not from the open-circuit voltage. This work is very significant for the design of low-concentrating system.

Microcrystalline (Si,Ge):H Solar Cells

2003 ◽  
Vol 762 ◽  
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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