The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Alex Van Den Bossche - One of the best experts on this subject based on the ideXlab platform.
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Axial-Flux PM Machines With Variable Air Gap
IEEE Transactions on Industrial Electronics, 2014Co-Authors: Hendrik Vansompel, Peter Sergeant, Luc Dupre, Alex Van Den BosscheAbstract:Laminated soft magnetic steel is very often used to manufacture the stator cores of axial-flux PM machines. However, as the magnetic flux typically has main components parallel to the Lamination plane, different magnetic flux density levels may occur over the radial direction: High flux densities near the saturation level are found at the inner radius, while the Laminations at the outer radius are used inefficiently. To obtain a leveled magnetic flux density, this paper introduces a radially varying air gap: At the inner radius, the air gap is increased, while at the outer radius, the air gap remains unchanged. This results in equal flux densities in the different Lamination layers. As the total flux in the stator cores is decreased due to the variable air gap, the permanent-magnet thickness should be increased to compensate for this. The effect of a variable air gap is tested for both a low-grade non-oriented and a high-grade grain-oriented material. For both materials, the redistribution of the magnetic flux due to the variable air gap results in a significant decrease of the iron losses. In the presented prototype machine, the iron losses are reduced up to 8% by introducing a variable air gap. Finally, a prototype machine is constructed using an efficient manufacturing procedure to construct the laminated magnetic stator cores with variable air gap.
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Evaluation of a Simple Lamination Stacking Method for the Teeth of an Axial Flux Permanent-Magnet Synchronous Machine With Concentrated Stator Windings
IEEE Transactions on Magnetics, 2012Co-Authors: Hendrik Vansompel, Peter Sergeant, Luc Dupre, Alex Van Den BosscheAbstract:In this paper, a simple Lamination stacking method for the teeth of an axial flux permanent-magnet synchronous machine with concentrated stator windings is proposed. In this simple Lamination stacking method, only two Lamination profiles are used and are stacked alternately. To evaluate the performance of this stacking method, a comparison is made between the proposed method with two profiles and a conventional stacking method that uses different profiles for each Lamination layer, using a multilayer 2-D finite element model.
Luc Dupre - One of the best experts on this subject based on the ideXlab platform.
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Axial-Flux PM Machines With Variable Air Gap
IEEE Transactions on Industrial Electronics, 2014Co-Authors: Hendrik Vansompel, Peter Sergeant, Luc Dupre, Alex Van Den BosscheAbstract:Laminated soft magnetic steel is very often used to manufacture the stator cores of axial-flux PM machines. However, as the magnetic flux typically has main components parallel to the Lamination plane, different magnetic flux density levels may occur over the radial direction: High flux densities near the saturation level are found at the inner radius, while the Laminations at the outer radius are used inefficiently. To obtain a leveled magnetic flux density, this paper introduces a radially varying air gap: At the inner radius, the air gap is increased, while at the outer radius, the air gap remains unchanged. This results in equal flux densities in the different Lamination layers. As the total flux in the stator cores is decreased due to the variable air gap, the permanent-magnet thickness should be increased to compensate for this. The effect of a variable air gap is tested for both a low-grade non-oriented and a high-grade grain-oriented material. For both materials, the redistribution of the magnetic flux due to the variable air gap results in a significant decrease of the iron losses. In the presented prototype machine, the iron losses are reduced up to 8% by introducing a variable air gap. Finally, a prototype machine is constructed using an efficient manufacturing procedure to construct the laminated magnetic stator cores with variable air gap.
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Evaluation of a Simple Lamination Stacking Method for the Teeth of an Axial Flux Permanent-Magnet Synchronous Machine With Concentrated Stator Windings
IEEE Transactions on Magnetics, 2012Co-Authors: Hendrik Vansompel, Peter Sergeant, Luc Dupre, Alex Van Den BosscheAbstract:In this paper, a simple Lamination stacking method for the teeth of an axial flux permanent-magnet synchronous machine with concentrated stator windings is proposed. In this simple Lamination stacking method, only two Lamination profiles are used and are stacked alternately. To evaluate the performance of this stacking method, a comparison is made between the proposed method with two profiles and a conventional stacking method that uses different profiles for each Lamination layer, using a multilayer 2-D finite element model.
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modeling of electromagnetic phenomena in soft magnetic materials under unidirectional time periodic flux excitations
IEEE Transactions on Magnetics, 1999Co-Authors: Luc Dupre, Oriano Bottauscio, M Chiampi, Maurizio Repetto, Jan MelkebeekAbstract:We report on recent advances in the modeling of magnetic losses in steel Laminations used in electromagnetic devices. The integrated-Lamination moving dynamic Preisach model, used to evaluate the dynamic magnetization loops under distorted unidirectional flux patterns, is described. The main goal is the comparison of two numerical procedures, using the finite element-finite difference technique and the finite element-fixed point technique, respectively, each properly taking into account the hysteresis characteristics by the Preisach theory. Moreover, attention is paid to the identification of the material parameters entering the moving dynamic Preisach model. Finally, the two techniques are validated by the comparison of numerical experiments and measurements on two different materials. Here, global as well as local quantities in the Lamination structure are evaluated.
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the application of the preisach model in magnetodynamics theoretical and practical aspects
Journal of Magnetism and Magnetic Materials, 1994Co-Authors: D A Philips, Luc Dupre, Jan Cnops, Jan MelkebeekAbstract:Abstract In this paper the computation of the magnetodynamic fields in ferromagnetic Laminations is discussed. The fields are governed by a diffusion type of equation, modelling the hysteresis and eddy current effects in the Lamination. It is shown that the hysteresis effects should be taken into account properly while solving the equation. Using a single-valued approximation for the material characteristic during the computations, and introducing hysteresis post-hoc, allows considerable computational savings, but leads to inaccurate results. Various time-stepping schemes are discussed with regard to the computational effort they require to solve the diffusion equation. Finally, measurements are given that show good agreement with the computations, if the latter are carried out properly.
Pragasen Pillay - One of the best experts on this subject based on the ideXlab platform.
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Calibration of the Tangential Coil Sensor for the Measurement of Core Losses in Electrical Machine Laminations
IEEE Transactions on Energy Conversion, 2016Co-Authors: Natheer Alatawneh, Pragasen PillayAbstract:The measurement of core losses in electrical steel Laminations is considered an essential step in the machine design process. Accordingly, the calibration of the tangential field sensor for measurements of magnetic field strength H is of importance in core loss measurements for estimation of electrical machine efficiency. Due to the stray field between the Lamination surface and the tangential coil, a concern is raised regarding the certainty of the measured field. This paper presents a reliable technical approach to calibrate the tangential field sensor used in the investigation of core losses in electrical machine Laminations, which compensates for the drop in the actual field value. The proposed approach is based on developing a magnetizing circuit, which consists of two test Laminations. An array of Hall Effect sensors is used in this study as a reference for the tangential field. The calibration results show that the magnetic field strength measured at the specimen surface by the tangential coil is scaled down by 4.57% of the actual field. The results are verified experimentally and validated by finite-element simulations. Based on the obtained results, a correction factor is applied on pulsating and rotational core losses to attain more accurate data.
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advanced testing and modeling of magnetic materials including a new method of core loss separation for electrical machines
IEEE Transactions on Industry Applications, 2012Co-Authors: Maged Ibrahim, Pragasen PillayAbstract:This paper presents a new method for the separation of core loss components (hysteresis and eddy current) in Laminations exposed to high-frequency excitations. Accurate separation of core losses is achieved by calculating the hysteresis losses at each frequency taking into account the nonuniform flux distribution inside the Lamination. The results highlight that the assumption of constant hysteresis energy loss per cycle is only valid at low frequencies, where skin effect is negligible. The developed model is then used to study the effect of the annealing process on core loss components in Laminations exposed to high-frequency excitations. Core loss measurements are performed on different Laminations at several frequencies in the range of 20-4000 Hz. A comparison of the separated core loss components shows that a huge reduction in the hysteresis losses is achieved by annealing, while the annealing process increases the eddy-current loss component at high frequencies and high flux densities. The results are then analyzed by comparing the separated eddy-current loss with an analytical eddy-current loss model that accounts for the nonuniform distribution of the magnetic field.
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advanced testing and modeling of magnetic materials including a new method of core loss separation for electrical machines
Energy Conversion Congress and Exposition, 2011Co-Authors: Maged Ibrahim, Pragasen PillayAbstract:This paper presents a new method for the separation of core loss components (hysteresis and eddy current) in Laminations exposed to high frequency excitations. Accurate separation of core losses is achieved by calculating the hysteresis losses at each frequency taking into account the non-uniform flux distribution inside the Lamination. The results highlight that the assumption of constant hysteresis energy loss per cycle is only valid at low frequencies, where skin effect is negligible. The developed model is then used to study the effect of the annealing process on core loss components in Laminations exposed to high frequency excitations. Core loss measurements are performed on different Laminations at several frequencies in the range of 20 Hz − 4000 Hz. A comparison of the separated core loss components shows that a huge reduction in the hysteresis loss is achieved by annealing, while the annealing process increases the eddy current loss component at high frequencies and high flux densities. The results are then analyzed by comparing the separated eddy current loss with an analytical eddy current loss model that accounts for the non-uniform distribution of the magnetic field.
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Magnetic Characteristics and Excess Eddy Current Losses
2009 IEEE Industry Applications Society Annual Meeting, 2009Co-Authors: Yu Zhang, Ming-c. Cheng, Pragasen PillayAbstract:To study the fundamental essence of excess losses and to achieve an accurate core loss separation formula, a dynamic finite element model for the non-linear hysteresis loop of Laminations has been established. In the model, Maxwell's Equations are solved for the hysteresis character in the magnetic Lamination, using the Galerkin finite element method, where the hysteresis is represented by an energetic hysteresis model. Based on the simulation results, the magnetic characteristics, skin effect, time delay and magnetic field distribution are discussed. Then core losses, especially excess losses, affected by the magnetic characteristics are carefully examined. It is concluded that excess current losses are due to the non-uniform magnetic field distribution resulting from the skin effect and the non-linear diffusion of magnetic flux from the boundary to the inside of the Lamination.
Jan Melkebeek - One of the best experts on this subject based on the ideXlab platform.
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modeling of electromagnetic phenomena in soft magnetic materials under unidirectional time periodic flux excitations
IEEE Transactions on Magnetics, 1999Co-Authors: Luc Dupre, Oriano Bottauscio, M Chiampi, Maurizio Repetto, Jan MelkebeekAbstract:We report on recent advances in the modeling of magnetic losses in steel Laminations used in electromagnetic devices. The integrated-Lamination moving dynamic Preisach model, used to evaluate the dynamic magnetization loops under distorted unidirectional flux patterns, is described. The main goal is the comparison of two numerical procedures, using the finite element-finite difference technique and the finite element-fixed point technique, respectively, each properly taking into account the hysteresis characteristics by the Preisach theory. Moreover, attention is paid to the identification of the material parameters entering the moving dynamic Preisach model. Finally, the two techniques are validated by the comparison of numerical experiments and measurements on two different materials. Here, global as well as local quantities in the Lamination structure are evaluated.
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calculation of eddy currents and associated losses in electrical steel Laminations
IEEE Conference on Electromagnetic Field Computation, 1999Co-Authors: Johan Gyselinck, Jan Melkebeek, Lieven Vandevelde, Patrick Dular, Francois Henrotte, W LegrosAbstract:Starting from the well known analytical formula for the eddy current losses in electrical steel Laminations, saturation and edge effects are studied by means of 1D and 2D finite element models of a single Lamination. A novel method for directly including the laminated core energy dissipation in a time stepped 2D model of a complete (rotating) machine is proposed. By way of example the method is applied to a tooth model with enforced flux waveforms.
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the application of the preisach model in magnetodynamics theoretical and practical aspects
Journal of Magnetism and Magnetic Materials, 1994Co-Authors: D A Philips, Luc Dupre, Jan Cnops, Jan MelkebeekAbstract:Abstract In this paper the computation of the magnetodynamic fields in ferromagnetic Laminations is discussed. The fields are governed by a diffusion type of equation, modelling the hysteresis and eddy current effects in the Lamination. It is shown that the hysteresis effects should be taken into account properly while solving the equation. Using a single-valued approximation for the material characteristic during the computations, and introducing hysteresis post-hoc, allows considerable computational savings, but leads to inaccurate results. Various time-stepping schemes are discussed with regard to the computational effort they require to solve the diffusion equation. Finally, measurements are given that show good agreement with the computations, if the latter are carried out properly.
Hendrik Vansompel - One of the best experts on this subject based on the ideXlab platform.
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Axial-Flux PM Machines With Variable Air Gap
IEEE Transactions on Industrial Electronics, 2014Co-Authors: Hendrik Vansompel, Peter Sergeant, Luc Dupre, Alex Van Den BosscheAbstract:Laminated soft magnetic steel is very often used to manufacture the stator cores of axial-flux PM machines. However, as the magnetic flux typically has main components parallel to the Lamination plane, different magnetic flux density levels may occur over the radial direction: High flux densities near the saturation level are found at the inner radius, while the Laminations at the outer radius are used inefficiently. To obtain a leveled magnetic flux density, this paper introduces a radially varying air gap: At the inner radius, the air gap is increased, while at the outer radius, the air gap remains unchanged. This results in equal flux densities in the different Lamination layers. As the total flux in the stator cores is decreased due to the variable air gap, the permanent-magnet thickness should be increased to compensate for this. The effect of a variable air gap is tested for both a low-grade non-oriented and a high-grade grain-oriented material. For both materials, the redistribution of the magnetic flux due to the variable air gap results in a significant decrease of the iron losses. In the presented prototype machine, the iron losses are reduced up to 8% by introducing a variable air gap. Finally, a prototype machine is constructed using an efficient manufacturing procedure to construct the laminated magnetic stator cores with variable air gap.
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Evaluation of a Simple Lamination Stacking Method for the Teeth of an Axial Flux Permanent-Magnet Synchronous Machine With Concentrated Stator Windings
IEEE Transactions on Magnetics, 2012Co-Authors: Hendrik Vansompel, Peter Sergeant, Luc Dupre, Alex Van Den BosscheAbstract:In this paper, a simple Lamination stacking method for the teeth of an axial flux permanent-magnet synchronous machine with concentrated stator windings is proposed. In this simple Lamination stacking method, only two Lamination profiles are used and are stacked alternately. To evaluate the performance of this stacking method, a comparison is made between the proposed method with two profiles and a conventional stacking method that uses different profiles for each Lamination layer, using a multilayer 2-D finite element model.
