Measuring transistor dynamic loadlines and breakdown currents under large-signal high-frequency operating conditions

1998 ◽  
Author(s):  
J. Verspecht ◽  
D. Schreurs
Keyword(s):  
High Frequency ◽  
Operating Conditions ◽  
Large Signal

scholarly journals Gaining Insights in Loading Events for Wind Turbine Drivetrain Prognostics

2020 ◽  
Author(s):  
Pieter-Jan Daems ◽  
Y. Guo ◽  
S. Sheng ◽  
C. Peeters ◽  
P. Guillaume ◽  
...  
Keyword(s):  
High Frequency ◽  
Failure Modes ◽  
Measurement Data ◽  
Wind Farms ◽  
Frequency Measurement ◽  
Operating Conditions ◽  
Failure Data ◽  
The World ◽  
Operations And Maintenance ◽  
History Of

Abstract Wind energy is one of the largest sources of renewable energy in the world. To further reduce the operations and maintenance (O&M) costs of wind farms, it is essential to be able to accurately pinpoint the root causes of different failure modes of interest. An example of such a failure mode that is not yet fully understood is white etching cracks (WEC). This can cause the bearing lifetime to be reduced to 5–10% of its design value. Multiple hypotheses are available in literature concerning its cause. To be able to validate or disprove these hypotheses, it is essential to have historic high-frequency measurement data (e.g., load and vibration levels) available. In time, this will allow linking to the history of the turbine operating data with failure data. This paper discusses the dynamic loading on the turbine during certain events (e.g., emergency stops, run-ups, and during normal operating conditions). By combining the number of specific events that each turbine has seen with the severity of each event, it becomes possible to assess which turbines are most likely to show signs of damage.

Effect of operating conditions on current density distribution and high frequency resistance in a segmented PEM fuel cell

2012 ◽  
Vol 37 (9) ◽  
pp. 7736-7744 ◽  
Author(s):  
Dietmar Gerteisen ◽  
Nada Zamel ◽  
Christian Sadeler ◽  
Florian Geiger ◽  
Victor Ludwig ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Density Distribution ◽  
Current Density ◽  
High Frequency ◽  
Current Density Distribution ◽  
Pem Fuel Cell ◽  
Operating Conditions

scholarly journals Flame response to high-frequency oscillations in a cryogenic oxygen/hydrogen rocket combustor

2019 ◽  
Author(s):  
N. Fdida ◽  
J. Hardi ◽  
H. Kawashima ◽  
B. Knapp ◽  
M. Oschwald ◽  
...  
Keyword(s):  
High Frequency ◽  
Acoustic Resonance ◽  
High Amplitude ◽  
Operating Conditions ◽  
Test Facility ◽  
Response Analysis ◽  
Rocket Engines ◽  
Acoustic Oscillations ◽  
Spatially Resolved ◽  
Flame Response

Experiments presented in this paper were conducted with the BKH rocket combustor at the European Research and Technology Test Facility P8, located at DLR Lampoldshausen. This combustor is dedicated to study the effects of high magnitude instabilities on oxygen/hydrogen flames, created by forcing high-frequency (HF) acoustic resonance of the combustion chamber. This work addresses the need for highly temporally and spatially resolved visualization data, in operating conditions representative of real rocket engines, to better understand the flame response to high amplitude acoustic oscillations. By combining ONERA and DLR materials and techniques, the optical setup of this experiment has been improved to enhance the existing database with more highly resolved OH* imaging to allow detailed response analysis of the flame. OH* imaging is complemented with simultaneous visible imaging and compared to each other here for their ability to capture flame dynamics.

A Stochastic Large-Signal Model for Printed High-Frequency Rectifiers Used for Efficient Generation of Higher Harmonics

2020 ◽  
Vol 68 (6) ◽  
pp. 2151-2160
Author(s):  
Kevin Neumann ◽  
Laura Kuhnel ◽  
Fabian Langer ◽  
Andreas Rennings ◽  
Niels Benson ◽  
...  
Keyword(s):  
High Frequency ◽  
Large Signal ◽  
Signal Model ◽  
Higher Harmonics ◽  
Efficient Generation

High Frequency Inversion Capacitance Measurements for 6H-SiC n-MOS Capacitors from 450 to 600 °C

2008 ◽  
Vol 600-603 ◽  
pp. 739-742 ◽  
Author(s):  
Ruby N. Ghosh ◽  
Reza Loloee ◽  
Tamara Isaacs-Smith ◽  
John R. Williams
Keyword(s):  
High Frequency ◽  
Operating Conditions ◽  
Oxide Semiconductor ◽  
Electrical Characteristics ◽  
Physical Processes ◽  
Large Area ◽  
Thermal Generation ◽  
Mos Capacitors ◽  
Mos Devices ◽  
Minority Carriers

The operation of metal-oxide-semiconductor (MOS) devices based on the semiconductor SiC in high temperature environments above 300 °C requires an understanding of the physical processes in these capacitor structures under operating conditions. In this study we have focused on the regime of inversion biasing, where the electrical characteristics of the device are dominated by minority carriers. We report on the direct observation of the high frequency inversion capacitance due to thermal generation of holes in 6H-SiC n-MOS capacitors between 450 and 600 °C by monitoring the 1MHz C-V characteristics of large area, 1000 μm diameter, capacitors in the dark. Our experimental results are consistent with a first order calculation based on the delta depletion approximation.

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