Search in Publications

Found 5164 publications

Reversible DC-to-DC converter for a dual voltage automotive system using zero voltage switching technique

Dan V. Nicolae Petre Scortaru Zoltán Puklus Mihai Cernat

Publication Name: 11th International Conference on Optimization of Electrical and Electronic Equipment Optim 2008

Publication Date: 2008-01-01

Volume: Unknown

Issue: Unknown

Page Range: 251-258

Description:

A novel hysteretic controller for a bi-directional dc-dc converter with ZVS and interleaving for dual voltage systems in automobiles is presented. A variable frequency extended band hysteretic current control method is proposed. In comparison with classical fixed frequency current control PWM, the reverse polarity peak current needed for ZVS operation is kept constant Inductor current ripple decreases with load reduction. Automatic changes in operation between buck and boost modes are accomplished without transient currents. Converter simulations are carried out using Matlab/Simulink platform.

Open Access: Yes

DOI: 10.1109/OPTIM.2008.4602417

Analysis of a numerical method developed for estimation of the heat transfer coefficient obtained during quenching

No authors available

Publication Name: Proceedings of the 17th IFHTSE Congress

Publication Date: 2008-01-01

Volume: 2

Issue:

Page Range: 816-819

Description:

A numerical method for prediction of the Heat Transfer Coefficient (HTC) obtained during quenching is described in this paper. An iterative regularization algorithm is used to solve the inverse problem under study. The unknown HTC function is approximated by polynomial functions of surface temperature. The numerical method developed is verified by using the temperature data measured with a JIS silver probe.

Open Access: No

DOI: DOI not available

Analysis of a vector hysteresis measurement system

Miklós Kuczmann

Publication Name: Journal of Optoelectronics and Advanced Materials

Publication Date: 2008-01-01

Volume: 10

Issue: 7

Page Range: 1823-1827

Description:

The paper deals with the numerical analysis of a vector hysteresis measurement system which is now under construction. The measurement set up consists of an induction motor which rotor has been removed, and its windings have been replaced to a special two phase one which can generate homogeneous magnetic field inside the motor. A round shaped specimen can be inserted into the arrangement. The two orthogonal components of the magnetic field intensity and of the magnetic flux density vectors can be measured by H-coils and B-coils, respectively. The Finite Element Method (FEM) with the T, Φ - ΦD potential formulation has been applied in the simulations. The vector hysteresis property of the specimen has been approximated by the vector Preisach model, finally the nonlinear problem has been solved by the convergent fixed point technique. The aim of the present work is to focus on the design aspects of this kind of measurement system.

Open Access: Yes

DOI: DOI not available

Cooperating modelling methods for performance evaluation of interconnected infocommunication and business process systems

László Muka Gábor Lencse

Publication Name: Esm 2008 2008 European Simulation and Modelling Conference Modelling and Simulation 2008

Publication Date: 2008-01-01

Volume: Unknown

Issue: Unknown

Page Range: 404-411

Description:

This paper describes how the rapid and detailed modelling and simulation methods can be used to increase the efficiency of mixed simulation projects initiated to support the design of interconnected ICT (Information and Communication Technology) and BP (Business Process) systems. A system of cooperating rapid and detailed methods for critical and non- critical parts of systems is introduced in the phase of preliminary and detailed modelling. The method of translation of information of conceptual models that had been built prior to simulation is described, too. New methods using rapid models to model the ICT and BP systems functioning as environment for the detailed models are presented. A novel method for preliminary modelling based only on cooperating system of rapid models is described. © 2008 EUROSIS-ETI.

Open Access: Yes

DOI: DOI not available

Selection of tool materials for cold forming operations using a computerized decision support system

No authors available

Publication Name: Proceedings of the 17th IFHTSE Congress

Publication Date: 2008-01-01

Volume: 2

Issue:

Page Range: 773-775

Description:

A computerized decision support system (DSS) is outlined which is designated primarily to selcct the proper tool steel grades for various cold forming operations. This computerized system contains four data base: data base of cold forming operations and tools, of work materials, of cold forming tool materials and of wear resistant PVD coatings. The decision strategy makes it possible to select appropriate tool materials taking into consideration their most important material properties (wear resistance, toughness, compressive yield strength, tempering resistance, dimensional stability, machinability, and material price). The practical advantages of the developed decision support system are demonstrated on example.

Open Access: No

DOI: DOI not available

Modeling and simulation for the energy storage by ultracapacitor in urban rail car

No authors available

Publication Name: 3rd International Conference on Electrical and Control Technologies, ECT 2008

Publication Date: 2008-01-01

Volume:

Issue:

Page Range: 239-242

Description:

This paper focuses on the use of modeling and simulation for the renewable energy. An energy storage system for improving performance of electric vehicles is presented. The supercapacitor contributes to the rapid energy recovery associated with regenerative braking in electric vehicles. This power system allows the acceleration and deceleration of the vehicle with minimal loss of energy. Short-distance passenger traffic on electrified lines is a domain where brake energy recuperation might reduce the total energy consumption significantly. In this paper the results of a simulation model by Matlab for an urban-metro railcar is presented.

Open Access: No

DOI: DOI not available

Challenges and responses in the geo-engineering education

No authors available

Publication Name: Proceedings of the 1st International Conference on Education and Training in Geo-Engineering Sciences: Soil Mechanics, Geotechnical Engineering, Engineering Geology and Rock Mechanics

Publication Date: 2008-01-01

Volume:

Issue:

Page Range: 443-446

Description:

Structural engineers assess the geotechnical problems as difficult to model, complicated to calculate and full of crude approximations. In return, clear constraints hindering the practical use of advanced mechanical theories and computational software decrease the interest of geotechnicians in studying and applying them. In designing complex structures both sides restrict themselves in many cases to the exchange or prescription of some data given on interfaces. The paper presents an overviewon differences either loosing their importance or remaining significant between these structural and geotechnical perspectives. Educational consequences related to the Bologna-process are discussed. Role of case studies and understanding of the observational method's importance are stressed. The paper concludes that geotechnical education should and could correspond to the challenges with more conscious and better structured curricula. © 2008 Taylor & Francis Group, London.

Open Access: No

DOI: DOI not available

Measuring and control the hysteresis loop by using analog and digital integrators

Miklós Kuczmann Zoltán Pólik

Publication Name: Journal of Optoelectronics and Advanced Materials

Publication Date: 2008-01-01

Volume: 10

Issue: 7

Page Range: 1861-1865

Description:

We have managed to build up a computer controlled measurement system applying National Instruments Data Acquisiton card and National lnsturments LabVIEW software package. First, in a previous study, the specimen under test has been simulated by the Jiles-Atherton model of hysteresis, but simulated measurements have been performed using LabVIEW functions. Our main goal now is to control the magnetic flux density measured by using a toroidal shape core with a feedback controller. In this paper, we show the developed procedure which is able to measure the hysteresis characteristics applying analog and digital integrators, and to control the waveform of magnetic flux density determined from the induced voltage of the secondary coil wound on the toroidal shape core. Our experience is that the developed controller is robust. This work is an initial step of the vector hysteresis measurement system.

Open Access: Yes

DOI: DOI not available

Cooperating modelling methods for performance evaluation of interconnected infocommunication and business process systems

No authors available

Publication Name: ESM 2008 - 2008 European Simulation and Modelling Conference: Modelling and Simulation 2008

Publication Date: 2008-01-01

Volume:

Issue:

Page Range: 404-411

Description:

This paper describes how the rapid and detailed modelling and simulation methods can be used to increase the efficiency of mixed simulation projects initiated to support the design of interconnected ICT (Information and Communication Technology) and BP (Business Process) systems. A system of cooperating rapid and detailed methods for critical and non- critical parts of systems is introduced in the phase of preliminary and detailed modelling. The method of translation of information of conceptual models that had been built prior to simulation is described, too. New methods using rapid models to model the ICT and BP systems functioning as environment for the detailed models are presented. A novel method for preliminary modelling based only on cooperating system of rapid models is described. © 2008 EUROSIS-ETI.

Open Access: No

DOI: DOI not available