Institute for Fundamentals and Theory in Electrical Engineering

Sankt Radegund bei Graz, Austria

Institute for Fundamentals and Theory in Electrical Engineering

Sankt Radegund bei Graz, Austria
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Mohr M.,Christian Doppler Laboratory | Mohr M.,Institute for Fundamentals and Theory in Electrical Engineering | Biro O.,Christian Doppler Laboratory | Biro O.,Institute for Fundamentals and Theory in Electrical Engineering | And 3 more authors.
IECON Proceedings (Industrial Electronics Conference) | Year: 2013

This paper presents an extended finite element based model approach for permanent magnet synchronous machines considering dynamic eccentricity effects of the rotor. This includes additional displacement forces acting on rotor and stator as well as the influence of rotor eccentricity to the machine torque and the back electromotive force. Furthermore, the work flow for this model is shown. © 2013 IEEE.


Hettegger M.,Institute for Fundamentals and Theory in Electrical Engineering | Streibl B.,Traktionssysteme Austria GmbH | Biro O.,Institute for Fundamentals and Theory in Electrical Engineering | Neudorfer H.,Traktionssysteme Austria GmbH
COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering | Year: 2011

Purpose - For an accurate simulation of the temperature distribution inside an electrical machine a method for deriving the convective heat transfer coefficient numerically would be desirable. The purpose of this paper is to present a reliable simulation setup, which is able to reproduce the measured convective heat transfer coefficient at certain spots on the end windings of an electric machine. Design/methodology/approach - The heat flux density on certain spots on the end windings of an induction motor have been measured with heat flux sensors, in order to find out the convective heat transfer coefficient. To identify the air mass flow inside a cooling duct of an encapsulated cooling circuit during the operation of the motor, the pressure loss inside the duct has been measured.The measured data for temperature and air mass flow have been used as boundary conditions for the identification of the convective heat transfer coefficient with a commercial software for computational fluid dynamics (CFD). Findings - The measured data for the local convective heat transfer coefficients have been compared to the results of the numerical simulation for various rotational velocities. The quality of the simulated convective heat transfer coefficient depending on the rotational velocity meets the measured values. Owing to the used simplified model, the quantity of the measured values differ strongly around the simulated coefficient for the convective heat transfer. Originality/value - The derivation of the convective heat transfer is a challenging subject in CFD but has become more reliable with the invention of the SST and the SAS-SST turbulence model. In the present work, measurements on the end windings have been compared to simulation results derived with the SAS-SST turbulence model. © 2011 Emerald Group Publishing Limited.


Mohr M.,Institute for Fundamentals and Theory in Electrical Engineering | Biro O.,Institute for Fundamentals and Theory in Electrical Engineering | Stermecki A.,Institute for Fundamentals and Theory in Electrical Engineering | Diwoky F.,AVL List GmbH
IEEE Transactions on Magnetics | Year: 2014

This paper presents a finite element-based circuit model approach for permanent magnet synchronous machines, electrically excited synchronous machines, and wound rotor induction machines, taking skewing of the rotor or the stator into account. These models utilize lookup tables created by 2-D finite element simulations in advance. Inspired by the finite element multislice technique, a multiple evaluation of these lookup tables is performed to consider skewing. The resulting models are comparable with quasi-static finite element multislice models with voltage fed coils. The only difference is caused by interpolation errors. However, the simulation cost is significantly lower and the memory demand for the lookup tables is acceptable. © 1965-2012 IEEE.


Renhart W.,Institute for Fundamentals and Theory in Electrical Engineering | Magele C.,Institute for Fundamentals and Theory in Electrical Engineering | Hausberger S.,Institute for Internal Combustion Engines and Thermodynamics | Zallinger M.,Institute for Internal Combustion Engines and Thermodynamics | Luz R.,Institute for Internal Combustion Engines and Thermodynamics
SPEEDAM 2010 - International Symposium on Power Electronics, Electrical Drives, Automation and Motion | Year: 2010

The performance of Ni-MH batteries powering hybrid vehicles is mainly influenced by its operating conditions. A sophisticated battery management is necessary to maximize performance as well as life time. So an adequate battery model is required. This contribution deals with the design of such a model. To begin with a common electric circuit model of the battery is used. Variant battery characteristics given by the data sheet have been dressed into analytical expressions which will feed the electric network. Of substantial interest for all network parameters is the knowledge of the barttery temperature. With the aid of the finite element method, variant ambient and cooling conditions have been simulated in advance. Therefrom, the temperature behavior could be considered in the model. With the use of a real life driving ciycle, wherein the power request as well as the energy recuperation during a specified time period are given, the battery model has been proved. © 2010 IEEE.


Rainer S.,Institute for Fundamentals and Theory in Electrical Engineering | Biro O.,Institute for Fundamentals and Theory in Electrical Engineering | Stermecki A.,Institute for Fundamentals and Theory in Electrical Engineering | Stermecki A.,Christian Doppler Laboratory | And 2 more authors.
IEEE Transactions on Magnetics | Year: 2012

A comprehensive procedure for the frequency domain evaluation of transient finite element simulations of induction machines is presented. The proposed algorithm allows the determination of the magnetic air-gap flux density for arbitrary operational points under consideration of the rotor movement. The flux density harmonics can be determined on the stator as well as on the moving rotor surface. For skewed induction machines, an interpolation algorithm for the axial behavior of the flux density is included. The procedure is demonstrated for a skewed induction machine operating at nominal load. © 2012 IEEE.


Weilharter B.,Institute for Electrical Drives and Machines | Weilharter B.,Chrstn Doppler Laboratory For Multiphysical Simulation | Biro O.,Institute for Fundamentals and Theory in Electrical Engineering | Lang H.,ELIN Motoren GmbH | Rainer S.,Institute for Fundamentals and Theory in Electrical Engineering
COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering | Year: 2011

Purpose - The purpose of this paper is to set up a comprehensive numerical approach to estimate the 3D structural vibration and noise radiation of an induction machine. Design/methodology/approach - The rotating force waves, acting in the air gap of an induction machine and obtained by an electromagnetic finite element multi-slice simulation, are applied to the 3D structural finite element model and a structural harmonic simulation is performed. The sound emission due to the vibration of the surface of the machine is computed with a 3D boundary element model. Findings - The paper outlays problematic issues when setting up the numerical models, i.e. The structural finite element model. The material properties strongly affect the structural behaviour and therefore the radiated noise. Originality/value - The 3D force distribution in the air gap and the resulting vibrations are computed. The structural behaviour, i.e. The different vibrational behaviour of stator and surface is discussed. The correlation of the structural vibrations and the noise radiation is investigated. © 2011 Emerald Group Publishing Limited.


Wilhelm J.,Institute for Fundamentals and Theory in Electrical Engineering | Renhart W.,Institute for Fundamentals and Theory in Electrical Engineering
2016 13th International Conference on Synthesis, Modeling, Analysis and Simulation Methods and Applications to Circuit Design, SMACD 2016 | Year: 2016

Simulation times of electric circuits containing switching power supplies not only depend on the algorithms used for solving the network equations but also on the choice of the time-step-control strategy. While generic simulation packages use the estimated truncation error to find the optimum time step, in this work a more specialized approach was followed. After studying the analytic solution and the simulation results of a circuit utilizing a pulse-with-modulation scheme it was found, that the switching intervals form adequate time-steps. To prove this, a basic simulation software was implemented and several simulations were conducted. Finally, the simulation accuracy was improved by introducing additional time-steps and impact on the convergence speed and memory consumption was studied. © 2016 European Union.

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