A. Hamler - Academia.edu (original) (raw)

Papers by A. Hamler

Research paper thumbnail of Impact of Stator Pole Shape of Synchronous Motor on Torque

The paper presents pole modelling of small one phase 10 poles synchronous motor with permanent ma... more The paper presents pole modelling of small one phase 10 poles synchronous motor with permanent magnets. The purpose of stator pole modelling is to provide a reliable operation of the motor with in advance prescribed direction of rotation with 80 % of the rated voltage. For analysis of magnetic conditions the 2D finite element method was used. Intuitive and trial modelling procedures were used for pole modelling.

Research paper thumbnail of Interactive teaching of electromagnetic field by simultaneous FEM analysis

IEEE Transactions on Magnetics, 2006

Electromagnetic theory presents difficult task for the student. The essence of the problem is not... more Electromagnetic theory presents difficult task for the student. The essence of the problem is not the pretentious mathematical treating of the field, but in the field presentation and understanding of field interaction with the material. The paper presents our program tools (FIELD_EDU) for teaching of electromagnetic field, based on the finite element method (FEM). The program concept enables the student to build in the very simple way an arbitrary problem, without being burdened with specific demands of FEM at field analysis. When doing this, the students can help themselves with the library of simple geometrical objects, which have already predefined material properties and boundary conditions. The program tools enable a complete graphical and numerical analysis of one or more examples at the same time.

Research paper thumbnail of Torque calculation by Bernstein Bezier's surfaces

IEEE Transactions on Magnetics, 1995

In this paper a new algorithm for torque cakulation using Maxwell Stress Tensor Method is present... more In this paper a new algorithm for torque cakulation using Maxwell Stress Tensor Method is presented. To reduce the influence of the integration path selection on motor torque calculations an interpolation based on triangular Bezier surfaces has been used. Magnetic field has been calculated by the fmite element method using the magnetic vector potential. The calculation results have been tested on a onephase brushless motor used for all necessary measurements.

Research paper thumbnail of Accuracy of iron loss calculation in electrical machines by using different iron loss models

Journal of Magnetism and Magnetic Materials, 2003

... loss with flux density B kmaj at frequency f of fundamental elliptical harmonic, σ the ... th... more ... loss with flux density B kmaj at frequency f of fundamental elliptical harmonic, σ the ... the loss deduced for each of the two equivalent orthogonal alternating flux density components. The paper presents iron loss calculation in rotational electrical machines by using different iron ...

Research paper thumbnail of Permanent magnet synchronous motor with exterior-rotor: Distributed or concentrated windings – motor performance comparison

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 2006

... Bojan Štumberger, Gorazd Štumberger, Miralem Hadziselimovic, Ivan Zagradišnik, Anton Hamler a... more ... Bojan Štumberger, Gorazd Štumberger, Miralem Hadziselimovic, Ivan Zagradišnik, Anton Hamler and Mladen Trlep Faculty of Electrical Engineering and ... concentrated windings was determined by procedures established by Cros and Viarouge (2002) and by Chen (Hwang et al ...

Research paper thumbnail of Impact of shape of stator pole of one phase brushless motor on cogging torque

IEEE Transactions on Magnetics, 1996

Abstract The paper discusses the influence of the stator pole shape on the cogging torque of sing... more Abstract The paper discusses the influence of the stator pole shape on the cogging torque of single-phase brushless motors. With this motor, the necessary starting torque is achieved with the cogging torque. The shape of the pole is changed so that the asymmetry of the ...

Research paper thumbnail of The use of DRM for inverse problems of Poisson's equation

IEEE Transactions on Magnetics, 2000

The paper presents the use of the dual reciprocity boundary element method (DRM) for the solution... more The paper presents the use of the dual reciprocity boundary element method (DRM) for the solution of the inverse problem described with Poisson's equation. The DRM approach has been chosen because it is ideal for the treatment of the nonhomogeneous part of Poisson's equation that determines the source distribution of the inverse problem. The mixed “0-1” order boundary elements were

Research paper thumbnail of The measurement of power losses at high magnetic field densities or at small cross-section of test specimen using the averaging

Journal of Magnetism and Magnetic Materials, 2000

It is difficult to achieve sufficient accuracy of power loss measurement at high magnetic field d... more It is difficult to achieve sufficient accuracy of power loss measurement at high magnetic field densities where the magnetic field strength gets more and more distorted, or in cases where the influence of noise increases (small specimen cross section). The influence of averaging on the accuracy of power loss measurement was studied on the cast amorphous magnetic material Metglas 2605-TCA.

Research paper thumbnail of Measurement of alternating magnetic properties of grain-oriented materials using a round rotational single sheet tester

Physica B: Condensed Matter, 2006

The magnetic properties of grain-oriented material under rotational magnetic flux condition were ... more The magnetic properties of grain-oriented material under rotational magnetic flux condition were measured, using two different pairs of B coils with different angle with respect to the rolling direction. It is known that induced voltages in two perpendicularly positioned B coils do not represent the actual amplitude and the angular speed of vector B in the measuring region. Consequently, the control of the induced voltages in the B coils at different positions means that the sample is measured under different magnetic flux condition. This leads to a difference between the results of vector H and the rotational loss. r

Research paper thumbnail of Hysteresis model and examples of ferromagnetic materials

IEEE Transactions on Magnetics, 2003

Abstract This work deals with the application of the scalar product model to different ferromagne... more Abstract This work deals with the application of the scalar product model to different ferromagnetic materials. Different hysteresis curves and minor loops are measured to examine the behavior of the magnetization and to compare it with theoretical calculated ...

Research paper thumbnail of Impact of Stator Pole Shape of Synchronous Motor on Torque

The paper presents pole modelling of small one phase 10 poles synchronous motor with permanent ma... more The paper presents pole modelling of small one phase 10 poles synchronous motor with permanent magnets. The purpose of stator pole modelling is to provide a reliable operation of the motor with in advance prescribed direction of rotation with 80 % of the rated voltage. For analysis of magnetic conditions the 2D finite element method was used. Intuitive and trial modelling procedures were used for pole modelling.

Research paper thumbnail of Transient Calculation of Electromagnetic Field for Grounding System Based on Consideration of Displacement Current

IEEE Transactions on Magnetics, 2000

This paper shows the use of FEM for a second order time dependent electromagnetic field problem, ... more This paper shows the use of FEM for a second order time dependent electromagnetic field problem, around grounding systems (GS). Twenty-node isoparametric quadratic 3D finite element, three-node quadratic 1D finite element and a spatial transformation of the "infinite space" into the finite space are all applied to achieve better accuracy. Time integration is conducted with the Newmark algorithm. The applied program solution is suitable for any GS and isotropic/anisotropic soil properties as well as time-varying fault current.

Research paper thumbnail of Measurement of alternating magnetic properties of grain-oriented materials using a round rotational single sheet tester

Physica B: Condensed Matter, 2006

The magnetic properties of grain-oriented material under rotational magnetic flux condition were ... more The magnetic properties of grain-oriented material under rotational magnetic flux condition were measured, using two different pairs of B coils with different angle with respect to the rolling direction. It is known that induced voltages in two perpendicularly positioned B coils do not represent the actual amplitude and the angular speed of vector B in the measuring region. Consequently, the control of the induced voltages in the B coils at different positions means that the sample is measured under different magnetic flux condition. This leads to a difference between the results of vector H and the rotational loss. r

Research paper thumbnail of Variation of direct and quadrature axis inductances of single-sided linear reluctance motor

IEEE International Electric Machines and Drives Conference. IEMDC'99. Proceedings (Cat. No.99EX272), 1999

The paper describes the variation of the direct and quadrature axis inductance, the moving force ... more The paper describes the variation of the direct and quadrature axis inductance, the moving force and power factor of a singlasided linear reluctance motor (LRM) in dependency on different combination of direct and quadrature axis excitation. The magnetic conditions in the motor were analysed by the finite element method The moving force was calculated by the Virtual Work Method. Calculation results of moving forces at constant direct axis current components show a linear response of moving force in dependency on quadrature axis current component.

Research paper thumbnail of Analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation

IEEE Transactions on Magnetics, 2000

The paper presents the analysis of iron loss in interior permanent magnet synchronous motor over ... more The paper presents the analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation. The analysis is based on finite element method and uses the information on local flux density variation in the motor components. The total iron loss is calculated by summing up separately the hysteresis, classical eddy current and

Research paper thumbnail of Performance comparison of three-phase flux reversal permanent magnet motors in BLDC and BLAC operation mode

Journal of Magnetism and Magnetic Materials, 2008

ABSTRACT The paper presents a comparison of torque capability and flux-weakening performance of t... more ABSTRACT The paper presents a comparison of torque capability and flux-weakening performance of three-phase flux reversal permanent magnet motors with surface and inset permanent magnets. Finite element analysis is employed to determine the performance of each motor in BLDC and BLAC operation mode. It is shown that the torque capability and flux-weakening performance of surface or inset permanent magnet configuration is strongly dependent on the stator teeth number/rotor pole number combination.

Research paper thumbnail of Field homogeneity in a two-phase round rotational single sheet tester with one and both side shields

Journal of Magnetism and Magnetic Materials, 2003

Round rotational single sheet tester is used for the measurement of magnetic properties in rotati... more Round rotational single sheet tester is used for the measurement of magnetic properties in rotational and alternating magnetic fields. The influence of one and both side shields on the field homogeneity in the sample is investigated with finite element calculation. The aim of the calculation is to define the optimal position of one or both side shields in order to

Research paper thumbnail of Transient finite element magnetic field calculation method in the anisotropic magnetic material based on the measured magnetization curves

Journal of Magnetism and Magnetic Materials, 2006

A lot of magnetic materials are anisotropic. In the 3D finite element method calculation, anisotr... more A lot of magnetic materials are anisotropic. In the 3D finite element method calculation, anisotropy of the material is taken into account. Anisotropic magnetic material is described with magnetization curves for different magnetization directions. The 3D transient calculation of the rotational magnetic field in the sample of the round rotational single sheet tester with circular sample considering eddy currents is made and compared with the measurement to verify the correctness of the method and to analyze the magnetic field in the sample.

Research paper thumbnail of Passive magnetic bearing

Journal of Magnetism and Magnetic Materials, 2004

The paper presents a special design of a passive magnetic bearing with permanent magnets on the f... more The paper presents a special design of a passive magnetic bearing with permanent magnets on the fixed and the rotating part of the bearing. Peculiarity of the presented passive magnetic bearing is its ability to take radial and axial loads in both directions by using axially magnetized permanent magnets. A 3D finite element method (3D FEM) is used for analysis of magnetic conditions in the bearing. The performance of the presented magnetic bearing was determined by the Maxwell Stress Method. r

Research paper thumbnail of Increasing of output power capability in a six-phase flux-weakened permanent magnet synchronous motor with a third harmonic current injection

IEEE Transactions on Magnetics, 2003

This paper presents a FEM based analysis of output power capability improvement (OPC) in a six-ph... more This paper presents a FEM based analysis of output power capability improvement (OPC) in a six-phase flux-weakened permanent magnet synchronous motor with a harmonic current injection. It is shown that the flux-weakened permanent magnet synchronous motor with the third harmonic current injection is capable of producing more output torque per RMS current flowing through the windings than the same motor supplied with sinusoidal currents. The results of the analysis are partially verified with the measurements.

Research paper thumbnail of Impact of Stator Pole Shape of Synchronous Motor on Torque

The paper presents pole modelling of small one phase 10 poles synchronous motor with permanent ma... more The paper presents pole modelling of small one phase 10 poles synchronous motor with permanent magnets. The purpose of stator pole modelling is to provide a reliable operation of the motor with in advance prescribed direction of rotation with 80 % of the rated voltage. For analysis of magnetic conditions the 2D finite element method was used. Intuitive and trial modelling procedures were used for pole modelling.

Research paper thumbnail of Interactive teaching of electromagnetic field by simultaneous FEM analysis

IEEE Transactions on Magnetics, 2006

Electromagnetic theory presents difficult task for the student. The essence of the problem is not... more Electromagnetic theory presents difficult task for the student. The essence of the problem is not the pretentious mathematical treating of the field, but in the field presentation and understanding of field interaction with the material. The paper presents our program tools (FIELD_EDU) for teaching of electromagnetic field, based on the finite element method (FEM). The program concept enables the student to build in the very simple way an arbitrary problem, without being burdened with specific demands of FEM at field analysis. When doing this, the students can help themselves with the library of simple geometrical objects, which have already predefined material properties and boundary conditions. The program tools enable a complete graphical and numerical analysis of one or more examples at the same time.

Research paper thumbnail of Torque calculation by Bernstein Bezier's surfaces

IEEE Transactions on Magnetics, 1995

In this paper a new algorithm for torque cakulation using Maxwell Stress Tensor Method is present... more In this paper a new algorithm for torque cakulation using Maxwell Stress Tensor Method is presented. To reduce the influence of the integration path selection on motor torque calculations an interpolation based on triangular Bezier surfaces has been used. Magnetic field has been calculated by the fmite element method using the magnetic vector potential. The calculation results have been tested on a onephase brushless motor used for all necessary measurements.

Research paper thumbnail of Accuracy of iron loss calculation in electrical machines by using different iron loss models

Journal of Magnetism and Magnetic Materials, 2003

... loss with flux density B kmaj at frequency f of fundamental elliptical harmonic, σ the ... th... more ... loss with flux density B kmaj at frequency f of fundamental elliptical harmonic, σ the ... the loss deduced for each of the two equivalent orthogonal alternating flux density components. The paper presents iron loss calculation in rotational electrical machines by using different iron ...

Research paper thumbnail of Permanent magnet synchronous motor with exterior-rotor: Distributed or concentrated windings – motor performance comparison

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 2006

... Bojan Štumberger, Gorazd Štumberger, Miralem Hadziselimovic, Ivan Zagradišnik, Anton Hamler a... more ... Bojan Štumberger, Gorazd Štumberger, Miralem Hadziselimovic, Ivan Zagradišnik, Anton Hamler and Mladen Trlep Faculty of Electrical Engineering and ... concentrated windings was determined by procedures established by Cros and Viarouge (2002) and by Chen (Hwang et al ...

Research paper thumbnail of Impact of shape of stator pole of one phase brushless motor on cogging torque

IEEE Transactions on Magnetics, 1996

Abstract The paper discusses the influence of the stator pole shape on the cogging torque of sing... more Abstract The paper discusses the influence of the stator pole shape on the cogging torque of single-phase brushless motors. With this motor, the necessary starting torque is achieved with the cogging torque. The shape of the pole is changed so that the asymmetry of the ...

Research paper thumbnail of The use of DRM for inverse problems of Poisson's equation

IEEE Transactions on Magnetics, 2000

The paper presents the use of the dual reciprocity boundary element method (DRM) for the solution... more The paper presents the use of the dual reciprocity boundary element method (DRM) for the solution of the inverse problem described with Poisson's equation. The DRM approach has been chosen because it is ideal for the treatment of the nonhomogeneous part of Poisson's equation that determines the source distribution of the inverse problem. The mixed “0-1” order boundary elements were

Research paper thumbnail of The measurement of power losses at high magnetic field densities or at small cross-section of test specimen using the averaging

Journal of Magnetism and Magnetic Materials, 2000

It is difficult to achieve sufficient accuracy of power loss measurement at high magnetic field d... more It is difficult to achieve sufficient accuracy of power loss measurement at high magnetic field densities where the magnetic field strength gets more and more distorted, or in cases where the influence of noise increases (small specimen cross section). The influence of averaging on the accuracy of power loss measurement was studied on the cast amorphous magnetic material Metglas 2605-TCA.

Research paper thumbnail of Measurement of alternating magnetic properties of grain-oriented materials using a round rotational single sheet tester

Physica B: Condensed Matter, 2006

The magnetic properties of grain-oriented material under rotational magnetic flux condition were ... more The magnetic properties of grain-oriented material under rotational magnetic flux condition were measured, using two different pairs of B coils with different angle with respect to the rolling direction. It is known that induced voltages in two perpendicularly positioned B coils do not represent the actual amplitude and the angular speed of vector B in the measuring region. Consequently, the control of the induced voltages in the B coils at different positions means that the sample is measured under different magnetic flux condition. This leads to a difference between the results of vector H and the rotational loss. r

Research paper thumbnail of Hysteresis model and examples of ferromagnetic materials

IEEE Transactions on Magnetics, 2003

Abstract This work deals with the application of the scalar product model to different ferromagne... more Abstract This work deals with the application of the scalar product model to different ferromagnetic materials. Different hysteresis curves and minor loops are measured to examine the behavior of the magnetization and to compare it with theoretical calculated ...

Research paper thumbnail of Impact of Stator Pole Shape of Synchronous Motor on Torque

The paper presents pole modelling of small one phase 10 poles synchronous motor with permanent ma... more The paper presents pole modelling of small one phase 10 poles synchronous motor with permanent magnets. The purpose of stator pole modelling is to provide a reliable operation of the motor with in advance prescribed direction of rotation with 80 % of the rated voltage. For analysis of magnetic conditions the 2D finite element method was used. Intuitive and trial modelling procedures were used for pole modelling.

Research paper thumbnail of Transient Calculation of Electromagnetic Field for Grounding System Based on Consideration of Displacement Current

IEEE Transactions on Magnetics, 2000

This paper shows the use of FEM for a second order time dependent electromagnetic field problem, ... more This paper shows the use of FEM for a second order time dependent electromagnetic field problem, around grounding systems (GS). Twenty-node isoparametric quadratic 3D finite element, three-node quadratic 1D finite element and a spatial transformation of the "infinite space" into the finite space are all applied to achieve better accuracy. Time integration is conducted with the Newmark algorithm. The applied program solution is suitable for any GS and isotropic/anisotropic soil properties as well as time-varying fault current.

Research paper thumbnail of Measurement of alternating magnetic properties of grain-oriented materials using a round rotational single sheet tester

Physica B: Condensed Matter, 2006

The magnetic properties of grain-oriented material under rotational magnetic flux condition were ... more The magnetic properties of grain-oriented material under rotational magnetic flux condition were measured, using two different pairs of B coils with different angle with respect to the rolling direction. It is known that induced voltages in two perpendicularly positioned B coils do not represent the actual amplitude and the angular speed of vector B in the measuring region. Consequently, the control of the induced voltages in the B coils at different positions means that the sample is measured under different magnetic flux condition. This leads to a difference between the results of vector H and the rotational loss. r

Research paper thumbnail of Variation of direct and quadrature axis inductances of single-sided linear reluctance motor

IEEE International Electric Machines and Drives Conference. IEMDC'99. Proceedings (Cat. No.99EX272), 1999

The paper describes the variation of the direct and quadrature axis inductance, the moving force ... more The paper describes the variation of the direct and quadrature axis inductance, the moving force and power factor of a singlasided linear reluctance motor (LRM) in dependency on different combination of direct and quadrature axis excitation. The magnetic conditions in the motor were analysed by the finite element method The moving force was calculated by the Virtual Work Method. Calculation results of moving forces at constant direct axis current components show a linear response of moving force in dependency on quadrature axis current component.

Research paper thumbnail of Analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation

IEEE Transactions on Magnetics, 2000

The paper presents the analysis of iron loss in interior permanent magnet synchronous motor over ... more The paper presents the analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation. The analysis is based on finite element method and uses the information on local flux density variation in the motor components. The total iron loss is calculated by summing up separately the hysteresis, classical eddy current and

Research paper thumbnail of Performance comparison of three-phase flux reversal permanent magnet motors in BLDC and BLAC operation mode

Journal of Magnetism and Magnetic Materials, 2008

ABSTRACT The paper presents a comparison of torque capability and flux-weakening performance of t... more ABSTRACT The paper presents a comparison of torque capability and flux-weakening performance of three-phase flux reversal permanent magnet motors with surface and inset permanent magnets. Finite element analysis is employed to determine the performance of each motor in BLDC and BLAC operation mode. It is shown that the torque capability and flux-weakening performance of surface or inset permanent magnet configuration is strongly dependent on the stator teeth number/rotor pole number combination.

Research paper thumbnail of Field homogeneity in a two-phase round rotational single sheet tester with one and both side shields

Journal of Magnetism and Magnetic Materials, 2003

Round rotational single sheet tester is used for the measurement of magnetic properties in rotati... more Round rotational single sheet tester is used for the measurement of magnetic properties in rotational and alternating magnetic fields. The influence of one and both side shields on the field homogeneity in the sample is investigated with finite element calculation. The aim of the calculation is to define the optimal position of one or both side shields in order to

Research paper thumbnail of Transient finite element magnetic field calculation method in the anisotropic magnetic material based on the measured magnetization curves

Journal of Magnetism and Magnetic Materials, 2006

A lot of magnetic materials are anisotropic. In the 3D finite element method calculation, anisotr... more A lot of magnetic materials are anisotropic. In the 3D finite element method calculation, anisotropy of the material is taken into account. Anisotropic magnetic material is described with magnetization curves for different magnetization directions. The 3D transient calculation of the rotational magnetic field in the sample of the round rotational single sheet tester with circular sample considering eddy currents is made and compared with the measurement to verify the correctness of the method and to analyze the magnetic field in the sample.

Research paper thumbnail of Passive magnetic bearing

Journal of Magnetism and Magnetic Materials, 2004

The paper presents a special design of a passive magnetic bearing with permanent magnets on the f... more The paper presents a special design of a passive magnetic bearing with permanent magnets on the fixed and the rotating part of the bearing. Peculiarity of the presented passive magnetic bearing is its ability to take radial and axial loads in both directions by using axially magnetized permanent magnets. A 3D finite element method (3D FEM) is used for analysis of magnetic conditions in the bearing. The performance of the presented magnetic bearing was determined by the Maxwell Stress Method. r

Research paper thumbnail of Increasing of output power capability in a six-phase flux-weakened permanent magnet synchronous motor with a third harmonic current injection

IEEE Transactions on Magnetics, 2003

This paper presents a FEM based analysis of output power capability improvement (OPC) in a six-ph... more This paper presents a FEM based analysis of output power capability improvement (OPC) in a six-phase flux-weakened permanent magnet synchronous motor with a harmonic current injection. It is shown that the flux-weakened permanent magnet synchronous motor with the third harmonic current injection is capable of producing more output torque per RMS current flowing through the windings than the same motor supplied with sinusoidal currents. The results of the analysis are partially verified with the measurements.