scholarly journals Nonlinear Power Inductors for Large Current Crest Factors

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Alexander Stadler ◽  
Tobias Stolzke ◽  
Christof Gulden
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Practical Method ◽  
Active Power ◽  
Electrical Measurements ◽  
Large Current ◽  
Efficient Construction ◽  
Package Density ◽  
Power Inductors ◽  
Saturable Inductor

A practical method is presented: how to adjust the inductance curve of a nonlinear (saturable) inductor with respect to a desired shape. For this purpose, a nonlinear model was developed based on finite element method (FEM). It is shown how a highly efficient construction with low stray fields and maximum package density can be achieved. Different prototype inductors were realized to illustrate the practical capability of photovoltaic (PV) inverters as well as active power factor correction (PFC) applications. All simulations are verified by means of experimental data drawn from electrical measurements.

scholarly journals Simulative investigation of ring creep on a planetary bearing of a wind turbine gearbox

2021 ◽  
Author(s):  
Jonas Gnauert ◽  
Felix Schlüter ◽  
Georg Jacobs ◽  
Dennis Bosse ◽  
Stefan Witter
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Sensitivity Analysis ◽  
Planetary Gear ◽  
The Finite Element Method ◽  
Relative Movement ◽  
Wind Turbine Gearbox ◽  
Interference Fit ◽  
Planetary Gears ◽  
Module Coefficient

AbstractWind turbines (WT) must be further optimized concerning availability and reliability. One of the major reasons of WT downtime is the failure of gearbox bearings. Some of these failures occur, due to the ring creep phenomenon, which is mostly detected in the planetary bearings. The ring creep phenomenon describes a relative movement of the outer ring to the planetary gear. In order to improve the understanding of ring creep, the finite element method (FEM) is used to simulate ring creep in planetary gears. First, a sensitivity analysis is carried out on a small bearing size (NU205), to characterize relevant influence parameters for ring creep—considered parameters are teeth module, coefficient of friction, interference fit and normal tooth forces. Secondly, a full-scale planetary bearing (SL185030) of a 1MW WT is simulated and verified with experimental data.

scholarly journals Identification of DC Thermal Steady-State Differential Inductance of Ferrite Power Inductors

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3854
Author(s):  
Salvatore Musumeci ◽  
Luigi Solimene ◽  
Carlo Stefano Ragusa
Keyword(s):  
Steady State ◽  
Input Voltage ◽  
Switching Frequency ◽  
Ohmic Losses ◽  
Steady State Temperature ◽  
Wide Range ◽  
Average Current ◽  
Power Inductors ◽  
Saturable Inductor ◽  
Thermal Steady State

In this paper, we propose a method for the identification of the differential inductance of saturable ferrite inductors adopted in DC–DC converters, considering the influence of the operating temperature. The inductor temperature rise is caused mainly by its losses, neglecting the heating contribution by the other components forming the converter layout. When the ohmic losses caused by the average current represent the principal portion of the inductor power losses, the steady-state temperature of the component can be related to the average current value. Under this assumption, usual for saturable inductors in DC–DC converters, the presented experimental setup and characterization method allow identifying a DC thermal steady-state differential inductance profile of a ferrite inductor. The curve is obtained from experimental measurements of the inductor voltage and current waveforms, at different average current values, that lead the component to operate from the linear region of the magnetization curve up to the saturation. The obtained inductance profile can be adopted to simulate the current waveform of a saturable inductor in a DC–DC converter, providing accurate results under a wide range of switching frequency, input voltage, duty cycle, and output current values.

A method to quantify hand-transmitted vibration exposure based on the biodynamic stress concept

2007 ◽  
Vol 221 (8) ◽  
pp. 847-861 ◽  
Author(s):  
R G Dong ◽  
D E Welcome ◽  
J Z Wu
Keyword(s):  
Experimental Data ◽  
High Frequency ◽  
Practical Method ◽  
The Other ◽  
Equivalent Model ◽  
Frequency Effect ◽  
Vibration Exposure ◽  
Stress Cycle ◽  
Vibration Induced White Finger ◽  
Frequency Weightings

This study generally hypothesized that the vibration-induced biodynamic stress and number of its cycles in a substructure of the hand-arm system play an important role in the development of vibration-induced disorders in the substructure. As the first step to test this hypothesis, the specific aims of this study were to develop a practical method to quantify the biodynamic stress-cycle measure, to compare it with ISO-weighted and unweighted accelerations, and to assess its potential for applications. A mechanical-equivalent model of the system was established using reported experimental data. The model was used to estimate the average stresses in the fingers and palm. The frequency weightings of the stresses in these substructures were derived using the proposed stress-cycle measure. This study found the frequency dependence of the average stress distributed in the fingers is different from that in the palm. Therefore, this study predicted that the frequency dependencies of finger disorders could also be different from those of the disorders in the palm, wrist, and arms. If vibration-induced white finger (VWF) is correlated better with unweighted acceleration than with ISO-weighted acceleration, the biodynamic stress distributed in the fingers is likely to play a more important role in the development of VWF than is the biodynamic stress distributed in the other substructures of the hand-arm system. The results of this study also suggest that the ISO weighting underestimates the high-frequency effect on the finger disorder development but it may provide a reasonable risk assessment of the disorders in the wrist and arm.

scholarly journals Low voltage and large current DC superconducting power cable designs for 10 km to 100km transmission line using experimental data of Ishikari project

2019 ◽  
Vol 1293 ◽  
pp. 012067 ◽  
Author(s):  
Satarou Yamaguchi ◽  
Takeo Yamada ◽  
Takashi Iitsuka ◽  
Akio Sato ◽  
Toru Sawamura ◽  
...  
Keyword(s):  
Experimental Data ◽  
Transmission Line ◽  
Low Voltage ◽  
Power Cable ◽  
Large Current

Research of Flat Crush Performance and Processing Technology for Dual-Core Honeycomb Paperboard

2010 ◽  
Vol 174 ◽  
pp. 521-524
Author(s):  
Ju Han ◽  
Wei Chi Pei ◽  
Xiao Bo Cui
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Simulation Analysis ◽  
Production Equipment ◽  
Hebei Province ◽  
Processing Technology ◽  
The Finite Element Method ◽  
Compression Performance ◽  
Compression Properties ◽  
Dual Core

To solve the conflict between cost and compressive strength of honeycomb paperboard, dual-core honeycomb paperboard is designed. Based on the processing technology of single-core paperboard, the processing technology of dual-core honeycomb is identified. Using production equipment of Tang Hai Yuan Ming Tangshan, Hebei Province, Ltd. Honeycomb, 110g/m2 and 220g/m2 paper core composed of 20mm thick dual-core honeycomb samples is produced. Through flat compression properties and the finite element method, using two kinds of honeycomb performance of the simulation analysis of experimental data and simulation analysis by the dual data Verify, the level dual-core honeycomb has been a substantial increase in compression performance. Based on dual-core honeycomb paperboard, multi-core paperboard can be designed and produced.

A Numerical Study of the Hydrodynamics of Reversing Flows Around a Cylinder

1994 ◽  
Vol 116 (4) ◽  
pp. 202-208 ◽  
Author(s):  
K. Nakajima ◽  
Y. Kallinderis ◽  
I. Sibetheros ◽  
R. W. Miksad ◽  
K. Lambrakos
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Stokes Equations ◽  
Numerical Study ◽  
Offshore Structures ◽  
Two Dimensions ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Random Behavior ◽  
Marching Scheme

A numerical study of the nonlinear and random behavior of flow-induced forces on offshore structures and experimental verification of the results are presented. The numerical study is based on a finite-element method for the unsteady incompressible Navier-Stokes equations in two dimensions. The momentum equations combined with a pressure correction equation are solved employing fourth-order artificial dissipation with a nonstaggered grid, instead of the more commonly used staggered meshes. The solution is advanced in time with a combined explicit and implicit marching scheme. Emphasis is placed on study of reversing flows around a cylinder. Comparisons with experimental data evaluate accuracy and robustness of the method.

Modification of Pre-Cracked Charpy Specimens for Surveillance Specimen Programs

2009 ◽  
Author(s):  
Boris Margolin ◽  
Vladimir Nikolaev ◽  
Valentin Fomenko ◽  
Lev Ryadkov
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Fracture Toughness ◽  
Finite Element ◽  
Brittle Fracture ◽  
Stress And Strain ◽  
Test Results ◽  
Deep Side ◽  
Strain Fields ◽  
Calculation Analysis

Application of pre-cracked Charpy specimens with various depth of side-grooves is considered for fracture toughness prediction. Recommendations for prediction of temperature dependence of fracture toughness are given when using small-sized specimens with deep side-grooves. Test results of about 500 specimens, cut from materials with various degrees of embrittlement are presented. On the basis of 3D calculations by finite element method the procedure used in standard ASTM E 1921 for calculation of Ke and J, is developed for bending specimens with deep side-grooves. An attempt is undertaken to explain the obtained experimental data from the standpoints of the available criteria of brittle fracture based on calculation analysis of stress and strain fields (SSF) of SE(B)-10 specimens with various depths of side-grooves.

Finite Element Simulation of RC Beam Strengthened with FRP

2012 ◽  
Vol 446-449 ◽  
pp. 3229-3232
Author(s):  
Chao Jiang Fu
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Finite Element Simulation ◽  
Fiber Reinforced Polymer ◽  
Rc Beam ◽  
The Finite Element Method ◽  
Reinforced Polymer ◽  
Element Simulation

The finite element modeling is established for reinforced concrete(RC) beam reinforced with fiber reinforced polymer (FRP) using the serial/parallel mixing theory. The mixture algorithm of serial/parallel rule is studied based on the finite element method. The results obtained from the finite element simulation are compared with the experimental data. The comparisons are made for load-deflection curves at mid-span. The numerical analysis results agree well with the experimental results. Numerical results indicate that the proposed procedure is validity.

Finite Element Calculation of Sintering Deformation Using Limited Experimental Data

2008 ◽  
Vol 606 ◽  
pp. 103-118 ◽  
Author(s):  
Jing Zhe Pan ◽  
Ruo Yu Huang
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Ceramic Powder ◽  
Material Model ◽  
Element Analysis ◽  
Ceramic Components ◽  
On Line ◽  
Element Method

Predicting the sintering deformation of ceramic powder compacts is very important to manufactures of ceramic components. In theory the finite element method can be used to calculate the sintering deformation. In practice the method has not been used very often by the industry for a very simple reason – it is more expensive to obtain the material data required in a finite element analysis than it is to develop a product through trial and error. A finite element analysis of sintering deformation requires the shear and bulk viscosities of the powder compact. The viscosities are strong functions of temperature, density and grain-size, all of which change dramatically in the sintering process. There are two ways to establish the dependence of the viscosities on the microstructure: (a) by using a material model and (b) by fitting the experimental data. The materials models differ from each other widely and it can be difficult to know which one to use. On the other hand, obtaining fitting functions is very time consuming. To overcome this difficulty, Pan and his co-workers developed a reduced finite element method (Kiani et. al. J. Eur. Ceram. Soc., 2007, 27, 2377-2383; Huang and Pan, J. Eur. Ceram. Soc., available on line, 2008) which does not require the viscosities; rather the densification data (density as function of time) is used to predict sintering deformation. This paper provides an overview of the reduced method and a series of case studies.

The Meyer–Neldel Rule in Conduction Mechanism of the Electrospun ZnO Nanofibers

NANO ◽  
2016 ◽  
Vol 11 (03) ◽  
pp. 1650025 ◽  
Author(s):  
Andrzej Stafiniak ◽  
Marek Tłaczała
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Conduction Mechanism ◽  
Deep Level ◽  
Electrical Measurements ◽  
Thermally Activated ◽  
Theoretical Assumptions ◽  
Different Temperatures ◽  
Zno Nanofibers ◽  
Improved Model

An analytical model describing the conductivity of ZnO nanofibers depending on the grains size is proposed. The research is based on the thermal dc electrical measurements of a single electrospun ZnO nanofiber calcined at different temperatures. In the our previous research, we showed that electrical conduction of ZnO nanofibers is mainly thermally activated. The activation energy of conductivity was strongly dependent on the grain size, which in turn depended on the calcination temperature. This could be due to migration of a point defect in the grain of ZnO and could change the carrier concentration. Our recent studies have shown that ZnO nanofibers behavior is consistent with the Meyer–Neldel rule. This indicates an exponential energy distribution of deep level traps in the material. Based on the theoretical assumptions and experimental data, the improved model of conductivity in a single ZnO nanofiber calcined at different temperatures was proposed.

Sign in / Sign up

Export Citation Format

Share Document