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http://hdl.handle.net/10985/22636
A Novel and General Approach for Solving the Ion-Flow Field Problem by a Regularization Technique
CHENG, QiWen; ZOU, Jun; CLENET, Stephane
In order to have a better convergence and accuracy for solving the ion-flow field problem, a novel and general numerical approach is proposed. In the past, the framework of the traditional mesh based method has a dilemma that the Kapzov boundary condition can be imposed properly, and it must have two loops: the “well-posed” problem is solved in the inner loop and the secant based method is applied to impose the Kapzov assumption in the outer loop. In contrast, the proposed method solves the ion flow field problem from the perspective of the inverse problem. The original boundary value problem is transformed into a regularized optimization problem based on the prior information about the smooth ion distribution on the conductors. The objective function is separated into two parts and minimized by the alternating direction iterative method. In contrast to the traditional methods, the proposed method has removed the redundant iterations and the contentious simplifications. Numerical experiments show that the performance of the proposed method is superior to the traditional method and the results obtained by the proposed method agree better with the physical law than the traditional method. the new method presents a general and rigorous way to analysis the ion-flow field problem.
Wed, 01 Dec 2021 00:00:00 GMThttp://hdl.handle.net/10985/226362021-12-01T00:00:00ZCHENG, QiWenZOU, JunCLENET, StephaneIn order to have a better convergence and accuracy for solving the ion-flow field problem, a novel and general numerical approach is proposed. In the past, the framework of the traditional mesh based method has a dilemma that the Kapzov boundary condition can be imposed properly, and it must have two loops: the “well-posed” problem is solved in the inner loop and the secant based method is applied to impose the Kapzov assumption in the outer loop. In contrast, the proposed method solves the ion flow field problem from the perspective of the inverse problem. The original boundary value problem is transformed into a regularized optimization problem based on the prior information about the smooth ion distribution on the conductors. The objective function is separated into two parts and minimized by the alternating direction iterative method. In contrast to the traditional methods, the proposed method has removed the redundant iterations and the contentious simplifications. Numerical experiments show that the performance of the proposed method is superior to the traditional method and the results obtained by the proposed method agree better with the physical law than the traditional method. the new method presents a general and rigorous way to analysis the ion-flow field problem.Temperature-dependent modelling of magnetic ageing of FeSi electrical steels
http://hdl.handle.net/10985/23007
Temperature-dependent modelling of magnetic ageing of FeSi electrical steels
HELBLING, H.; TOTO JAMIL, Meryeme; DUMONT, Myriam; BENABOU, Abdelkader; CLENET, Stephane
This paper deals with the temperature-dependent modelling of iron losses in the context of magnetic ageing of electricals steel used in high power electrical machines. First, two electrical steel sheet grades were heat treated at three temperatures in order to study the ageing effect evolution as a function of temperature. Results show a significant increase in iron losses for both steel grades. Then, considering the link between the macroscopic magnetic properties evolution (effect) and the microscopic precipitation (cause), the Johnson – Mehl – Avrami – Kolmogorov (JMAK) law describing the kinetics of precipitation was applied to model the time evolution of magnetic ageing. By coupling this model with the Arrhenius’ law, a model is developed to be able to predict the ageing for several temperature levels.
Thu, 01 Dec 2022 00:00:00 GMThttp://hdl.handle.net/10985/230072022-12-01T00:00:00ZHELBLING, H.TOTO JAMIL, MeryemeDUMONT, MyriamBENABOU, AbdelkaderCLENET, StephaneThis paper deals with the temperature-dependent modelling of iron losses in the context of magnetic ageing of electricals steel used in high power electrical machines. First, two electrical steel sheet grades were heat treated at three temperatures in order to study the ageing effect evolution as a function of temperature. Results show a significant increase in iron losses for both steel grades. Then, considering the link between the macroscopic magnetic properties evolution (effect) and the microscopic precipitation (cause), the Johnson – Mehl – Avrami – Kolmogorov (JMAK) law describing the kinetics of precipitation was applied to model the time evolution of magnetic ageing. By coupling this model with the Arrhenius’ law, a model is developed to be able to predict the ageing for several temperature levels.Application of the JMAK precipitation law in iron loss modelling to account for magnetic ageing effect
http://hdl.handle.net/10985/21459
Application of the JMAK precipitation law in iron loss modelling to account for magnetic ageing effect
JAMIL, Meryeme; DUMONT, Myriam; BENABOU, Abdelkader; CLENET, Stephane; MIPO, Jean-Claude
This article deals with the modelling of iron losses due to the magnetic ageing of electrical steels used in energy conversion devices. This phenomenon is the consequence of irreversible mechanisms in the material which can be triggered by the operating temperature of electrical devices. At first, an experimental study is carried out at 180◦ C in order to assess the effect of isothermal ageing on electromagnetic properties of a magnetic steel sample. The results show that, during the thermal ageing, the hysteresis losses and the coercive field increase. These experimental observations, mainly caused by the formation of precipitates at the material microstructural scale, are then discussed. Considering the link between the effect of magnetic ageing on macroscopic magnetic properties (effect) and the microscopic precipitation (cause), the Johnson – Mehl – Avrami – Kolmogorov (JMAK) law describing the kinetics of precipitation was applied to model the time evolution of magnetic ageing. Once this approach was validated, it is proposed to integrate the JMAK law in the Steinmetz iron loss model.
Sat, 01 Jan 2022 00:00:00 GMThttp://hdl.handle.net/10985/214592022-01-01T00:00:00ZJAMIL, MeryemeDUMONT, MyriamBENABOU, AbdelkaderCLENET, StephaneMIPO, Jean-ClaudeThis article deals with the modelling of iron losses due to the magnetic ageing of electrical steels used in energy conversion devices. This phenomenon is the consequence of irreversible mechanisms in the material which can be triggered by the operating temperature of electrical devices. At first, an experimental study is carried out at 180◦ C in order to assess the effect of isothermal ageing on electromagnetic properties of a magnetic steel sample. The results show that, during the thermal ageing, the hysteresis losses and the coercive field increase. These experimental observations, mainly caused by the formation of precipitates at the material microstructural scale, are then discussed. Considering the link between the effect of magnetic ageing on macroscopic magnetic properties (effect) and the microscopic precipitation (cause), the Johnson – Mehl – Avrami – Kolmogorov (JMAK) law describing the kinetics of precipitation was applied to model the time evolution of magnetic ageing. Once this approach was validated, it is proposed to integrate the JMAK law in the Steinmetz iron loss model.Solving Magnetodynamic Problems via Normal Form Method
http://hdl.handle.net/10985/22540
Solving Magnetodynamic Problems via Normal Form Method
UGWUANYI, Nnaemeka S.; CLENET, Stephane; KESTELYN, Xavier; THOMAS, Olivier
Closed-form formulations are difficult to find when the material behavior law is nonlinear. A linear approximation, on the other
hand, has a very narrow range of validity. In this communication, the Normal Form (NF) method is employed to solve a 1-D nonlinear magnetodynamic problem. The discrete model is formulated in a state-space form suitable for NF applications. The resulting system is then expanded on a linear mode basis to cubic order. Analytical solutions are obtained using the NF technique and compared to traditional solutions. The results show the cubic polynomial adequately approximates the problem, and the NF solution is valid for some range of magnetic field intensity.
Tue, 01 Mar 2022 00:00:00 GMThttp://hdl.handle.net/10985/225402022-03-01T00:00:00ZUGWUANYI, Nnaemeka S.CLENET, StephaneKESTELYN, XavierTHOMAS, OlivierClosed-form formulations are difficult to find when the material behavior law is nonlinear. A linear approximation, on the other
hand, has a very narrow range of validity. In this communication, the Normal Form (NF) method is employed to solve a 1-D nonlinear magnetodynamic problem. The discrete model is formulated in a state-space form suitable for NF applications. The resulting system is then expanded on a linear mode basis to cubic order. Analytical solutions are obtained using the NF technique and compared to traditional solutions. The results show the cubic polynomial adequately approximates the problem, and the NF solution is valid for some range of magnetic field intensity.Mesh Deformation Based on Radial Basis Function Interpolation Applied to Low-Frequency Electromagnetic Problem
http://hdl.handle.net/10985/16535
Mesh Deformation Based on Radial Basis Function Interpolation Applied to Low-Frequency Electromagnetic Problem
HENNERON, Thomas; PIERQUIN, Antoine; CLENET, Stephane
In order to take into account a modification of the geometry during an optimization process or due to a physical phenomenon, a deformation of the elements of the spatial discretization is preferable to conserve a conformal mesh and to apply the Finite Element (FE) method. To perform the displacement of nodes, interpolation method can be investigated in this context. In this paper, the Radial Basis Function (RBF) interpolation method is applied for low frequency electromagnetic problems solved by the FE method.. A 2D magnetostatic example is considered to study the influence of the parameters of the RBF interpolation. To test the extension in 3D, a non destructive testing (NDT) problem is treated where the shape of the crack is modified by applying the proposed method.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/165352019-01-01T00:00:00ZHENNERON, ThomasPIERQUIN, AntoineCLENET, StephaneIn order to take into account a modification of the geometry during an optimization process or due to a physical phenomenon, a deformation of the elements of the spatial discretization is preferable to conserve a conformal mesh and to apply the Finite Element (FE) method. To perform the displacement of nodes, interpolation method can be investigated in this context. In this paper, the Radial Basis Function (RBF) interpolation method is applied for low frequency electromagnetic problems solved by the FE method.. A 2D magnetostatic example is considered to study the influence of the parameters of the RBF interpolation. To test the extension in 3D, a non destructive testing (NDT) problem is treated where the shape of the crack is modified by applying the proposed method.Magnetic ageing investigation of bulk low-carbon silicon steel
http://hdl.handle.net/10985/20122
Magnetic ageing investigation of bulk low-carbon silicon steel
TOTO JAMIL, Meryeme; BENABOU, Abdelkader; CLENET, Stephane; SHIHAB, Sylvain; LE BELLU ARBENZ, Laure; MIPO, Jean-Claude
In this paper, the magnetic ageing of a bulk forged non-annealed magnetic core, used in claw pole synchronous machine, is investigated. The study is carried out by characterizing the material properties of two groups of samples subjected to a thermal ageing at 180 °C that corresponds to the maximum operating temperature of the claw pole rotor. The investigated characteristics are the electrical conductivity, the magnetic properties, the material microstructure and the Vickers hardness. They were characterized along with the ageing time. The results show that, during the thermal ageing, the hysteresis losses and the Vickers hardness have been affected by the magnetic ageing, whereas the electric conductivity and the normal B-H curve have not been modified. The microstructure analyses showed that carbides precipitates were the main cause behind the magnetic ageing. Moreover, the comparison between the results of two groups of samples revealed the possibility that the magnetic ageing of the material could have started during the manufacturing process of the magnetic core.
Fri, 01 Jan 2021 00:00:00 GMThttp://hdl.handle.net/10985/201222021-01-01T00:00:00ZTOTO JAMIL, MeryemeBENABOU, AbdelkaderCLENET, StephaneSHIHAB, SylvainLE BELLU ARBENZ, LaureMIPO, Jean-ClaudeIn this paper, the magnetic ageing of a bulk forged non-annealed magnetic core, used in claw pole synchronous machine, is investigated. The study is carried out by characterizing the material properties of two groups of samples subjected to a thermal ageing at 180 °C that corresponds to the maximum operating temperature of the claw pole rotor. The investigated characteristics are the electrical conductivity, the magnetic properties, the material microstructure and the Vickers hardness. They were characterized along with the ageing time. The results show that, during the thermal ageing, the hysteresis losses and the Vickers hardness have been affected by the magnetic ageing, whereas the electric conductivity and the normal B-H curve have not been modified. The microstructure analyses showed that carbides precipitates were the main cause behind the magnetic ageing. Moreover, the comparison between the results of two groups of samples revealed the possibility that the magnetic ageing of the material could have started during the manufacturing process of the magnetic core.Magneto-thermal characterization of bulk forged magnetic steel used in claw pole machine
http://hdl.handle.net/10985/20121
Magneto-thermal characterization of bulk forged magnetic steel used in claw pole machine
TOTO JAMIL, Meryeme; BENABOU, Abdelkader; CLENET, Stephane; SHIHAB, Sylvain; LE BELLU ARBENZ, Laure; MIPO, Jean-Claude
During the operation of Claw Pole (CP) machines, and for some operating loads, the magnetic core temperature can reach 180°C in some hot spots. As a consequence, the core electromagnetic properties may considerably change, impacting the machine performances. In such a case, a deep knowledge of the electromagnetic behavior as a function of the temperature is required. In this paper, we present a dedicated study of the CP rotor made from a forged magnetic steel. In fact, the CP magnetic properties heterogeneity and the claw shape made it necessary to extract specific samples that are characterized with a miniaturized Single Sheet Tester (SST). To that end, this work proposes a specific methodology to characterize the electromagnetic properties of the CP rotor material as a function of the temperature in order to better predict the machine electrical performances, especially regarding the iron losses.
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/10985/201212020-01-01T00:00:00ZTOTO JAMIL, MeryemeBENABOU, AbdelkaderCLENET, StephaneSHIHAB, SylvainLE BELLU ARBENZ, LaureMIPO, Jean-ClaudeDuring the operation of Claw Pole (CP) machines, and for some operating loads, the magnetic core temperature can reach 180°C in some hot spots. As a consequence, the core electromagnetic properties may considerably change, impacting the machine performances. In such a case, a deep knowledge of the electromagnetic behavior as a function of the temperature is required. In this paper, we present a dedicated study of the CP rotor made from a forged magnetic steel. In fact, the CP magnetic properties heterogeneity and the claw shape made it necessary to extract specific samples that are characterized with a miniaturized Single Sheet Tester (SST). To that end, this work proposes a specific methodology to characterize the electromagnetic properties of the CP rotor material as a function of the temperature in order to better predict the machine electrical performances, especially regarding the iron losses.Finite-Element Model Reduction of Surface-Mounted Permanent Magnet Machines by Exploitation of Geometrical Periodicity
http://hdl.handle.net/10985/16566
Finite-Element Model Reduction of Surface-Mounted Permanent Magnet Machines by Exploitation of Geometrical Periodicity
AL EIT, Moustafa; HENNERON, Thomas; CLENET, Stephane
This paper presents a methodology that allows taking advantage of the geometrical periodicity of electrical machines together with the modeling of rotor motion. It enables by means of the discrete Fourier transform (DFT) to reduce the large-scale system obtained from the finite-element model to several smaller independent subsystems, allowing a shortening of the computational time. Due to DFT properties, the computational time can be more reduced especially when we consider the inter-dependence of the spectral components under either balanced or unbalanced supply condition. In addition, a further reduction is possible in the case of balanced regimes where the distribution of the eventual numerical solution is governed by a limited number of prevailing harmonics.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/165662018-01-01T00:00:00ZAL EIT, MoustafaHENNERON, ThomasCLENET, StephaneThis paper presents a methodology that allows taking advantage of the geometrical periodicity of electrical machines together with the modeling of rotor motion. It enables by means of the discrete Fourier transform (DFT) to reduce the large-scale system obtained from the finite-element model to several smaller independent subsystems, allowing a shortening of the computational time. Due to DFT properties, the computational time can be more reduced especially when we consider the inter-dependence of the spectral components under either balanced or unbalanced supply condition. In addition, a further reduction is possible in the case of balanced regimes where the distribution of the eventual numerical solution is governed by a limited number of prevailing harmonics.Comparative study of methods for optimization of electromagnetic devices with uncertainty
http://hdl.handle.net/10985/13420
Comparative study of methods for optimization of electromagnetic devices with uncertainty
DENG, Siyang; BRISSET, Stéphane; CLENET, Stephane
This paper compares different probabilistic optimization methods dealing with uncertainties. Reliability-Based Design Optimization is presented as well as various approaches to calculate the probability of failure. They are compared in terms of precision and number of evaluations on mathematical and electromagnetic design problems to highlight the most effective methods.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/134202018-01-01T00:00:00ZDENG, SiyangBRISSET, StéphaneCLENET, StephaneThis paper compares different probabilistic optimization methods dealing with uncertainties. Reliability-Based Design Optimization is presented as well as various approaches to calculate the probability of failure. They are compared in terms of precision and number of evaluations on mathematical and electromagnetic design problems to highlight the most effective methods.Reduction of a Finite Element Parametric Model using Adaptive POD Methods – Application to uncertainty quantification
http://hdl.handle.net/10985/10554
Reduction of a Finite Element Parametric Model using Adaptive POD Methods – Application to uncertainty quantification
HENNERON, Thomas; IDA, Nathan; CLENET, Stephane
Model Order Reduction (MOR) methods enable reduction of the computation time when dealing with parametrized numerical models. Among these methods, the Proper Orthogonal Decomposition (POD) method seems to be a good candidate because of its simplicity and its accuracy. In the literature, the offline/online approach is generally applied but is not always required especially if the study focuses on the device without any coupling with others. In this paper, we propose a method to construct adaptively the reduced model while its utilization which limits the evaluations of the full model when appropriate. A stochastic magnetostatic example with 14 uncertain parameters is studied by applying the Monte Carlo simulation method to illustrate the proposed procedure. In that case, it appears that the complexity of this method does not depend on the number of input parameters and so is not affected by the curse of dimensionality.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/105542015-01-01T00:00:00ZHENNERON, ThomasIDA, NathanCLENET, StephaneModel Order Reduction (MOR) methods enable reduction of the computation time when dealing with parametrized numerical models. Among these methods, the Proper Orthogonal Decomposition (POD) method seems to be a good candidate because of its simplicity and its accuracy. In the literature, the offline/online approach is generally applied but is not always required especially if the study focuses on the device without any coupling with others. In this paper, we propose a method to construct adaptively the reduced model while its utilization which limits the evaluations of the full model when appropriate. A stochastic magnetostatic example with 14 uncertain parameters is studied by applying the Monte Carlo simulation method to illustrate the proposed procedure. In that case, it appears that the complexity of this method does not depend on the number of input parameters and so is not affected by the curse of dimensionality.