Design of a high-efficiency low-voltage axially modulated cusp-injected second-harmonic X-band gyrotron amplifier

1996 ◽  
Vol 24 (3) ◽  
pp. 678-686 ◽  
Author(s):  
W. Lawson ◽  
A. Grigoropoulos ◽  
A. Liu ◽  
G.P. Saraph ◽  
J. Rodgers ◽  
...  
Keyword(s):  
High Efficiency ◽  
Low Voltage ◽  
Second Harmonic ◽  
Gyrotron Amplifier ◽  
X Band

Design of a low-voltage, axially modulated, cusp-injected, third harmonic, X-band gyrotron amplifier experiment

1997 ◽  
Vol 44 (11) ◽  
pp. 2022-2028
Author(s):  
A. Liu ◽  
W. Lawson ◽  
A. Fernandez ◽  
J. Rodgers ◽  
W.W. Destler
Keyword(s):  
Low Voltage ◽  
Third Harmonic ◽  
Gyrotron Amplifier ◽  
X Band

scholarly journals Novel High-Efficiency High Step-Up DC–DC Converter with Soft Switching and Low Component Voltage Stress for Photovoltaic System

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1112
Author(s):  
Yu-En Wu ◽  
Jyun-Wei Wang
Keyword(s):  
High Voltage ◽  
Output Voltage ◽  
High Efficiency ◽  
Low Voltage ◽  
Leakage Inductance ◽  
Power Switch ◽  
Half Wave Voltage ◽  
Half Wave ◽  
Voltage Stress ◽  
Voltage Doubler

This study developed a novel, high-efficiency, high step-up DC–DC converter for photovoltaic (PV) systems. The converter can step-up the low output voltage of PV modules to the voltage level of the inverter and is used to feed into the grid. The converter can achieve a high step-up voltage through its architecture consisting of a three-winding coupled inductor common iron core on the low-voltage side and a half-wave voltage doubler circuit on the high-voltage side. The leakage inductance energy generated by the coupling inductor during the conversion process can be recovered by the capacitor on the low-voltage side to reduce the voltage surge on the power switch, which gives the power switch of the circuit a soft-switching effect. In addition, the half-wave voltage doubler circuit on the high-voltage side can recover the leakage inductance energy of the tertiary side and increase the output voltage. The advantages of the circuit are low loss, high efficiency, high conversion ratio, and low component voltage stress. Finally, a 500-W high step-up converter was experimentally tested to verify the feasibility and practicability of the proposed architecture. The results revealed that the highest efficiency of the circuit is 98%.

The Feasible Analysis of Transformer Fast Reenergizing with Neutral Point Ungrounded

2013 ◽  
Vol 732-733 ◽  
pp. 958-964
Author(s):  
Yao Zhao ◽  
Yu De Yang ◽  
Yan Hong Pan ◽  
Le Qi
Keyword(s):  
High Voltage ◽  
Power Supply ◽  
Low Voltage ◽  
Second Harmonic ◽  
Neutral Point ◽  
Inrush Current ◽  
Differential Protection ◽  
Time Saving ◽  
Magnetizing Inrush Current ◽  
Transformer Differential Protection

The feasibility of transformer fast reenergizing with neutral point ungrounded after the external fault being removed is analyzed in this paper. By calculating overvoltage and discriminating magnetizing inrush current, it analyzes four ways to restore power of transformer and chooses the optimal strategy which is safe and time-saving. The result shows that in the case of transformer neutral point ungrounded, closing the low-voltage circuit side breaker before the high-voltage, which can effectively limit over-voltage in a safe range. The second harmonic characteristic of magnetizing waveform may disappear, while the intermittent angle characteristics are still significant. With the help of the intermittent angle principle, transformer differential protection may not misuse. The average time for each customer interruption is reduced from 40 minutes to 10 minutes and saves an hour for engineer on the way back and forth. It will greatly improve power supply reliability.

High efficiency X-band magnetically insulated line oscillator with a separate cathode

2010 ◽  
Vol 17 (4) ◽  
pp. 043109 ◽  
Author(s):  
Renzhen Xiao ◽  
Wei Song ◽  
Zhimin Song ◽  
Jun Sun ◽  
Hao Shao ◽  
...  
Keyword(s):  
High Efficiency ◽  
X Band

scholarly journals Synergistic Interfacial and Doping Engineering of Heterostructured NiCo(OH)x-CoyW as an Efficient Alkaline Hydrogen Evolution Electrocatalyst

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruopeng Li ◽  
Hao Xu ◽  
Peixia Yang ◽  
Dan Wang ◽  
Yun Li ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
High Efficiency ◽  
Low Voltage ◽  
Electrochemical Etching ◽  
Synergistic Effects ◽  
Release Kinetics ◽  
Water Electrolysis ◽  
Water Dissociation ◽  
Practical Applications ◽  
Environmentally Friendly Process

AbstractTo achieve high efficiency of water electrolysis to produce hydrogen (H2), developing non-noble metal-based catalysts with considerable performance have been considered as a crucial strategy, which is correlated with both the interphase properties and multi-metal synergistic effects. Herein, as a proof of concept, a delicate NiCo(OH)x-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition, followed by an electrochemical etching-growth process, which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction, with an overpotential of 21 and 139 mV at 10 and 500 mA cm−2, respectively. Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)x/CoyW heterogeneous interface resulted in favorable electron redistribution and faster electron transfer efficiency. The amorphous NiCo(OH)x strengthened the water dissociation step, and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H2 desorption. In addition, NiCo(OH)x-CoyW exhibited desirable urea oxidation reaction activity for matching H2 generation with a low voltage of 1.51 V at 50 mA cm−2. More importantly, the synthesis and testing of the NiCo(OH)x-CoyW catalyst in this study were all solar-powered, suggesting a promising environmentally friendly process for practical applications.

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