scholarly journals Determination of the operating voltage for non-linear capacitors as turn-off snubbers in power electronic switches

1988 ◽  
Vol 7 (3) ◽  
pp. 146-148
Author(s):  
A. G. K. Lutsch ◽  
J. J. Schoeman ◽  
J. D. Van Wyk
Keyword(s):  
Measuring Method ◽  
Operating Voltage ◽  
Power Electronic ◽  
Non Linear ◽  
Electronic Switches

The use of non-linear capacitors improves the efficiency of turn-off snubbers for power electronic switches. The parameters for the determination of non-linear ferro-electric capacitors are discussed and a novel measuring method for the determination of the maximum operating voltage is suggested. The procedure to select ferro-electric capacitors is also discussed.

scholarly journals A non-linear turn-off snubber for power electronic switches

1985 ◽  
Vol 4 (4) ◽  
pp. 143-146 ◽  
Author(s):  
C. G. Steyn ◽  
J. D. Van Wyk
Keyword(s):  
Power Device ◽  
Power Electronic ◽  
Electronic Switch ◽  
Stored Energy ◽  
Auxiliary Power ◽  
Non Linear ◽  
Voltage Dependent ◽  
Electronic Switches ◽  
Linear Voltage

A novel suggestion for a non-linear turn-off snubber is simulated experimentally with linear capacitors and an auxiliary power electronic switch. Thus the principle and advantages of this concept is partly illustrated, particularly concerning the important reduction of reactive stored energy for the same switching dissipation in the main power device. The full advantages of the concept will be realised when a snubber capacitor with non-linear, voltage dependent dielectric is used. The work on this part of the solution is being continued.

Determination of efficiency of a five-level multilevel topology utilizing a single bidirectional-blocking-bidirectional-conducting switch

2020 ◽  
Vol 21 (2) ◽  
Author(s):  
Rabiya Rasheed ◽  
K. K. Saju ◽  
V. Bindu
Keyword(s):  
Numerical Simulation ◽  
Circuit Simulation ◽  
Analytical Calculation ◽  
Data Sheet ◽  
Multilevel Inverter ◽  
Power Electronic ◽  
Switching Losses ◽  
Cascaded Multilevel Inverter ◽  
Electronic Switches

AbstractNumerical simulation for calculation of losses of a new cascaded multilevel inverter (MLI) topology depending upon a bi-directional-blocking-bidirectional–conducting-switch is summarized in this paper. The numerical circuit simulation is performed in PSIM software by utilizing thermal models of power electronic switches. Calculation of conduction and switching losses of a 73 W inverter by relying on data sheet values has also been made. A comparison of efficiency of 73 W inverter using numerical simulation as well as analytical calculation has also been made. The new proposed inverter is a compound of both unidirectional as well as bidirectional power electronic switches challenging the attempt to reduce device count of the cascaded MLI.

Determination of Concrete Cube Strength from Used Samples / Určení Krychelné Pevnosti Betonu U Použitých Zkušebních Trámců

2012 ◽  
Vol 12 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Oldřich Sucharda ◽  
David Mikolášek ◽  
Jiří Brožovský
Keyword(s):  
Compressive Strength ◽  
Concrete Beams ◽  
Linear Analysis ◽  
Bending Tests ◽  
Cube Strength ◽  
Non Linear ◽  
Compressive Strength Of Concrete ◽  
Concrete Cube

Abstract This paper deals with the determination of compressive strength of concrete. Cubes, cylinders and re-used test beams were tested. The concrete beams were first subjected to three-point or fourpoint bending tests and then used for determination of the compressive strength of concrete. Some concrete beams were reinforced, while others had no reinforcement. Accuracy of the experiments and calculations was verified in a non-linear analysis.

scholarly journals Bias Truck Tire Deformation Analysis with Finite Element Modeling

2020 ◽  
Vol 10 (12) ◽  
pp. 4326
Author(s):  
Józef Pelc
Keyword(s):  
Incompressible Material ◽  
Axisymmetric Deformation ◽  
Thermal Shrinkage ◽  
Deformation Analysis ◽  
Truck Tire ◽  
Non Linear ◽  
Strain Relationship ◽  
Tire Modeling ◽  
Total Lagrangian Formulation

This paper presents a method for modeling of pneumatic bias tire axisymmetric deformation. A previously developed model of all-steel radial tire was expanded to include the non-linear stress–strain relationship for textile cord and its thermal shrinkage. Variable cord density and cord angle in the cord-rubber bias tire composite are the major challenges in pneumatic tire modeling. The variabilities result from the tire formation process, and they were taken into account in the model. Mechanical properties of the composite were described using a technique of orthotropic reinforcement overlaying onto isotropic rubber elements, treated as a hyperelastic incompressible material. Due to large displacements, the non-linear problem was solved using total Lagrangian formulation. The model uses MSC.Marc code with implemented user subroutines, allowing for the description of the tire specific properties. The efficiency of the model was verified in the simulation of mounting and inflation of an actual bias truck tire. The shrinkage negligence effect on cord forces and on displacements was examined. A method of investigating the influence of variation of cord angle in green body plies on tire apparent lateral stiffness was proposed. The created model is stabile, ensuring convergent solutions even with large deformations. Inflated tire sizes predicted by the model are consistent with the actual tire sizes. The distinguishing feature of the developed model from other ones is the exact determination of the cord angles in a vulcanized tire and the possibility of simulation with the tire mounting on the rim and with cord thermal shrinkage taken into account. The model may be an effective tool in bias tire design.

scholarly journals Determination of non-linear refractive index of laser crystals and ceramics via different optical techniques

2020 ◽  
Vol 8 ◽  
pp. 100065
Author(s):  
Laurent Lamaignère ◽  
Guido Toci ◽  
Barbara Patrizi ◽  
Matteo Vannini ◽  
Angela Pirri ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Techniques ◽  
Linear Refractive Index ◽  
Non Linear ◽  
Laser Crystals

Ermitteln von Lagefehlern bei Einlippenbohrern/Determination of position errors in single-lip drills

2021 ◽  
Vol 111 (05) ◽  
pp. 355-361
Author(s):  
Maximilian Schweigart ◽  
Hans-Christian Möhring
Keyword(s):  
Measuring Method ◽  
Polar Coordinates ◽  
Machining Forces ◽  
Actual Position ◽  
Position Errors ◽  
Machine Spindle ◽  
Laser Profile

Dieser Beitrag stellt eine berührungslose Messmethode zur Feststellung von Lagefehlern bei Einlippenbohrern vor, die auf der Verwendung eines Laser-Profilsensors basiert. Durch die Messung von Verlagerungen an mehreren Positionen entlang des langsam rotierenden Werkzeugschafts kann die Lage des Werkzeugs in Polarkoordinaten abgebildet werden. Das System bietet die Möglichkeit sowohl herstellungsbedingte Fehler als auch durch Bearbeitungskräfte und -momente verursachte Formänderungen des Werkzeugs nach verschiedenen Schnittwegen feststellen zu können.   This article introduces a non-contact measuring method, based on the use of a laser profile sensor to determine position errors in single-lip drills. By measuring displacements at several positions along the tool shaft with the machine spindle rotating slowly, the actual position of the tool can be mapped in polar coordinates. The system thus offers the potential to identify manufacturing-related errors as well as changes in the shape of the tool caused by machining forces and torques after different cutting paths.

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