Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508522
H. T. Anh, M. Hsieh
This digest investigates the demagnetization risk of permanent magnet-assisted synchronous reluctance machines (PMa-SynRM). PMa-SynRM is often designed with multilayer PMs/flux barriers to increase saliency and reluctance torque. Weaker or less PM (than that for IPM motor) is embedded into the rotor of PMa-SynRM, which can be demagnetized during high-performance operation (e.g., high armature reaction or current phase advance control). Demagnetization possibility of PM depends on factors such as temperature, armature current and design operating points and mostly occurs combining some of the above factors. The temperature distribution across the PM can be different and the operating points at different locations in the PM can also vary. This very likely causes local demagnetization within a PM. This work proposes a method to evaluate the demagnetization risk within a PM for all the PM layers of PMa-SynRM rotors. A model based on the magnetic circuit is first developed to calculate the operating points across the PM at the no-load and loaded condition. The magnet temperature distribution is then estimated with a commercial software. With the temperature and loaded operating points of the PM, the risk of local demagnetization can be predicted. This is validated using finite element analysis. From the analysis, a design method that can avoid demagnetization is then proposed. Experimental studies are conducted to validate the simulations.
{"title":"Analysis of Local Demagnetization in Magnet for PM-Assisted Synchronous Reluctance Motors.","authors":"H. T. Anh, M. Hsieh","doi":"10.1109/INTMAG.2018.8508522","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508522","url":null,"abstract":"This digest investigates the demagnetization risk of permanent magnet-assisted synchronous reluctance machines (PMa-SynRM). PMa-SynRM is often designed with multilayer PMs/flux barriers to increase saliency and reluctance torque. Weaker or less PM (than that for IPM motor) is embedded into the rotor of PMa-SynRM, which can be demagnetized during high-performance operation (e.g., high armature reaction or current phase advance control). Demagnetization possibility of PM depends on factors such as temperature, armature current and design operating points and mostly occurs combining some of the above factors. The temperature distribution across the PM can be different and the operating points at different locations in the PM can also vary. This very likely causes local demagnetization within a PM. This work proposes a method to evaluate the demagnetization risk within a PM for all the PM layers of PMa-SynRM rotors. A model based on the magnetic circuit is first developed to calculate the operating points across the PM at the no-load and loaded condition. The magnet temperature distribution is then estimated with a commercial software. With the temperature and loaded operating points of the PM, the risk of local demagnetization can be predicted. This is validated using finite element analysis. From the analysis, a design method that can avoid demagnetization is then proposed. Experimental studies are conducted to validate the simulations.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"13 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82640267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508194
Xuerong Li, Jingmeng Liu, A. Chen
This paper proposes a rotor permanent magnet array applied in the three degree-of-freedom (3-DOF) permanent magnet spherical actuator. To investigate the performance of the permanent magnet array, this paper presents an analytical model for calculating the magnetic field generated by the spherical rotor array using spherical harmonics. Compared with the numerical method 3-D finite element analysis, the spherical harmonics can obtain a closed-form function with the advantages of reasonable accuracy and rapid computational effort. Finally three structural parameters of rotor array are discussed by the analytical model.
{"title":"3-D Magnetic Field Analysis of a Permanent Magnet Spherical Actuator Using Spherical Harmonics","authors":"Xuerong Li, Jingmeng Liu, A. Chen","doi":"10.1109/INTMAG.2018.8508194","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508194","url":null,"abstract":"This paper proposes a rotor permanent magnet array applied in the three degree-of-freedom (3-DOF) permanent magnet spherical actuator. To investigate the performance of the permanent magnet array, this paper presents an analytical model for calculating the magnetic field generated by the spherical rotor array using spherical harmonics. Compared with the numerical method 3-D finite element analysis, the spherical harmonics can obtain a closed-form function with the advantages of reasonable accuracy and rapid computational effort. Finally three structural parameters of rotor array are discussed by the analytical model.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"1 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89342376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508236
J. You, X. Liao, R. Wang, H. Liang, J. Sykulski
The paper addresses the issue of the working point migration in non-linear permanent magnets (PM). Starting from the considerations of energy, a novel working-point migration model (WPM) is proposed which can be incorporated into a magnetic equivalent circuit (MEC). The static characteristic of a bistable polarized magnetic system (BPMS), as used in actuators, is calculated using the magnetic circuit method based on the WPM, while a finite element model (FEM) is also derived. The WPM based MEC model yields reasonable results, compared with FEM, of the latching force but with much faster calculation speeds. Furthermore, the working-point state of the PM is clearly illustrated. The test system of the BPMS prototype is established. It is shown that the WPM model provides accurate prediction of static characteristics of an electromagnetic system.
{"title":"A Nonlinear Permanent Magnet Working Point Migration Model and its Application to Simulation of a Polarized Magnetic Sys-tem.","authors":"J. You, X. Liao, R. Wang, H. Liang, J. Sykulski","doi":"10.1109/INTMAG.2018.8508236","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508236","url":null,"abstract":"The paper addresses the issue of the working point migration in non-linear permanent magnets (PM). Starting from the considerations of energy, a novel working-point migration model (WPM) is proposed which can be incorporated into a magnetic equivalent circuit (MEC). The static characteristic of a bistable polarized magnetic system (BPMS), as used in actuators, is calculated using the magnetic circuit method based on the WPM, while a finite element model (FEM) is also derived. The WPM based MEC model yields reasonable results, compared with FEM, of the latching force but with much faster calculation speeds. Furthermore, the working-point state of the PM is clearly illustrated. The test system of the BPMS prototype is established. It is shown that the WPM model provides accurate prediction of static characteristics of an electromagnetic system.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"112 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86217113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508745
R. Khokle, S. D. de Freitas, K. Esselle, M. Heimlich, F. Franco, D. Bokor
Every year millions of people around the world undergo orthopaedic surgeries with partial or complete joint replacements. However, according to the various arthroplasty registers around the world, about 10 % of the implants require re-surgery at some point in their lifetime [1]. About 80–90% of implant failures occur due to mechanical reasons [1–2]. It is proposed in [2], that micromotion of the orthopaedic implants during the limb movement can provide insights on the possible implant failure in the future. For this purpose, it is necessary to monitor the motion of metallic orthopaedic implants with the resolution of the order of tens of microns when the person moves a limb. In this paper, it is proposed to use a small sensor embedded inside the bone at a distance from the orthopaedic implant. The space available for such a sensor is limited to the cylindrical hole of dimensions 3 mm × 10 mm.
{"title":"Eddy Current-TMR Sensor for Micro-Motion Detection of Orthopaedic Implants","authors":"R. Khokle, S. D. de Freitas, K. Esselle, M. Heimlich, F. Franco, D. Bokor","doi":"10.1109/INTMAG.2018.8508745","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508745","url":null,"abstract":"Every year millions of people around the world undergo orthopaedic surgeries with partial or complete joint replacements. However, according to the various arthroplasty registers around the world, about 10 % of the implants require re-surgery at some point in their lifetime [1]. About 80–90% of implant failures occur due to mechanical reasons [1–2]. It is proposed in [2], that micromotion of the orthopaedic implants during the limb movement can provide insights on the possible implant failure in the future. For this purpose, it is necessary to monitor the motion of metallic orthopaedic implants with the resolution of the order of tens of microns when the person moves a limb. In this paper, it is proposed to use a small sensor embedded inside the bone at a distance from the orthopaedic implant. The space available for such a sensor is limited to the cylindrical hole of dimensions 3 mm × 10 mm.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"13 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78487466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508412
K. Matsuyama, I. Sasaki, S. Nakagawa, H. Era, M. Takezawa, Y. Horibe, S. Hata, C. Kaidou, T. Ogawa, S. Kubo
{"title":"Magnetic properties and crystal structure of high-purity Fe-(6, 6.5, 7) mass%Si alloys.","authors":"K. Matsuyama, I. Sasaki, S. Nakagawa, H. Era, M. Takezawa, Y. Horibe, S. Hata, C. Kaidou, T. Ogawa, S. Kubo","doi":"10.1109/INTMAG.2018.8508412","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508412","url":null,"abstract":"","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"202 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88895775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508376
P. Huang, M. Tsai, I. Jiang
Due to the features of high efficiency, high torque, and without using permanent magnets, the synchronous reluctance motors (SynRMs) have become popular in industry. Such advantages are contributed by the design of the rotor barriers and ribs that the flux flow path are arranged as shown in Fig. 1(a). However, the requirements of motors usually are not just high efficiency but some other more operation capabilities such as low vibration and easy start. Unfortunately, as compared with the industrial most commonly used induction motors (IMs), position sensors are additionally required for initiating starting of SynRMs [1], [2]. Moreover, the barriers and ribs of SynRMs may increase the risk of structure deformation as rotation. Hence, this paper proposes a novel design of applying the 3D bionic structure in the SynRMs with new flux path design to solve the said problems. Further, the additive manufacturing (3D printing) is adopted to fabricate the complicated prototype of the rotor.
{"title":"3D Structure Line Start Synchronous Reluctance Motor Design Based on Selective Laser Melting of 3D Printing.","authors":"P. Huang, M. Tsai, I. Jiang","doi":"10.1109/INTMAG.2018.8508376","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508376","url":null,"abstract":"Due to the features of high efficiency, high torque, and without using permanent magnets, the synchronous reluctance motors (SynRMs) have become popular in industry. Such advantages are contributed by the design of the rotor barriers and ribs that the flux flow path are arranged as shown in Fig. 1(a). However, the requirements of motors usually are not just high efficiency but some other more operation capabilities such as low vibration and easy start. Unfortunately, as compared with the industrial most commonly used induction motors (IMs), position sensors are additionally required for initiating starting of SynRMs [1], [2]. Moreover, the barriers and ribs of SynRMs may increase the risk of structure deformation as rotation. Hence, this paper proposes a novel design of applying the 3D bionic structure in the SynRMs with new flux path design to solve the said problems. Further, the additive manufacturing (3D printing) is adopted to fabricate the complicated prototype of the rotor.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"36 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73523863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508189
L. Friedrich, M. Curti, B. Gysen, J. Jansen, E. Lomonova
High-order methods have been subject of research over the last years to replace the time-consuming meshing operation of Finite Elements Method (FEM) by a structured grid, which is exploiting the tensor product. The problem formulation in these methods is generally the same, i.e., weak form implemented through the Bubnov-Galerkin method. First and second order polynomials functions used in FEM are replaced by high arbitrary-order polynomial functions because of their overall excellent accuracy and fast computation time. The Spectral Element Method (SEM) and Isogeometric Analysis (IGA) among others, are exploiting high order basis with established mathematical framework [1], [2], and available numerical tools [3]. In this paper, the solution for elliptic Laplace equation formulated with SEM and IGA are applied to 2D magnetostatic problems, including both linear and nonlinear materials. The obtained magnetic field distributions and post-processed parameters such as flux linkage, forces, and inductances are validated with FEM. A very low discrepancy is achieved which demonstrates the applicability of the proposed high-order methods, and enables integrated design-through-analysis of electrical machines. In this paper, SEM and IGA are applied to the analysis of two electrical machine benchmarks, in which a nonlinear iron characteristic is considered. Each of these methods uses different basis functions, quadrature rules, and space discretization, although both are based on the same Galerkin method. Modeling Solutions obtained from FEM are known to be very dependent on the quality of the triangular mesh [4]. Moreover, in FEM a curved geometry is approximated by linear elements which influences the accuracy, or comes at the cost of a high number of mesh elements. SEM divides the geometry into elements or patches, as exemplified in Fig. 1. Each patch is mapped to a unique square parent element, where calculations and matrix assembly are conducted. Legendre polynomials are used as basis functions. Lagrangian interpolation subsequently allows the computation of the solution on the Lobatto-Gauss-Legendre roots [1], and obtains the functional coefficients on the grid. IGA basis-functions are formed by the tensor-product of B-splines or NURBS (non-uniform rational B-splines), which is the industry-standard geometrical description used in computer aided design (CAD). The same basis functions allow to represent complex geometrical shapes [2], compute and visualize the solution. The physical domain is mapped to a rectangular computational domain, on which the basis functions and their gradients are known and where the calculations are conducted through numerical Gaussian quadratures. In both proposed methods, the geometry is discretized into 2D conforming patches where continuity is strongly imposed, forcing each basis function on the interface to match one-to-one. The formulation suited for 2D magnetostatic electrical machine modeling is further extended to incl
{"title":"High-order methods applied to electrical machine modeling.","authors":"L. Friedrich, M. Curti, B. Gysen, J. Jansen, E. Lomonova","doi":"10.1109/INTMAG.2018.8508189","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508189","url":null,"abstract":"High-order methods have been subject of research over the last years to replace the time-consuming meshing operation of Finite Elements Method (FEM) by a structured grid, which is exploiting the tensor product. The problem formulation in these methods is generally the same, i.e., weak form implemented through the Bubnov-Galerkin method. First and second order polynomials functions used in FEM are replaced by high arbitrary-order polynomial functions because of their overall excellent accuracy and fast computation time. The Spectral Element Method (SEM) and Isogeometric Analysis (IGA) among others, are exploiting high order basis with established mathematical framework [1], [2], and available numerical tools [3]. In this paper, the solution for elliptic Laplace equation formulated with SEM and IGA are applied to 2D magnetostatic problems, including both linear and nonlinear materials. The obtained magnetic field distributions and post-processed parameters such as flux linkage, forces, and inductances are validated with FEM. A very low discrepancy is achieved which demonstrates the applicability of the proposed high-order methods, and enables integrated design-through-analysis of electrical machines. In this paper, SEM and IGA are applied to the analysis of two electrical machine benchmarks, in which a nonlinear iron characteristic is considered. Each of these methods uses different basis functions, quadrature rules, and space discretization, although both are based on the same Galerkin method. Modeling Solutions obtained from FEM are known to be very dependent on the quality of the triangular mesh [4]. Moreover, in FEM a curved geometry is approximated by linear elements which influences the accuracy, or comes at the cost of a high number of mesh elements. SEM divides the geometry into elements or patches, as exemplified in Fig. 1. Each patch is mapped to a unique square parent element, where calculations and matrix assembly are conducted. Legendre polynomials are used as basis functions. Lagrangian interpolation subsequently allows the computation of the solution on the Lobatto-Gauss-Legendre roots [1], and obtains the functional coefficients on the grid. IGA basis-functions are formed by the tensor-product of B-splines or NURBS (non-uniform rational B-splines), which is the industry-standard geometrical description used in computer aided design (CAD). The same basis functions allow to represent complex geometrical shapes [2], compute and visualize the solution. The physical domain is mapped to a rectangular computational domain, on which the basis functions and their gradients are known and where the calculations are conducted through numerical Gaussian quadratures. In both proposed methods, the geometry is discretized into 2D conforming patches where continuity is strongly imposed, forcing each basis function on the interface to match one-to-one. The formulation suited for 2D magnetostatic electrical machine modeling is further extended to incl","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"6 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73232816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508784
M. M. Saari, Nazatul Sharreena Suhaimi, N. A. C. Lah, K. Sakai
In order to tailor the magnetic nanoparticles (MNPs) properties for intended applications, it is crucial to unravelling their fundamental dynamics with respect to excitation magnetic field. In this work, we report on the development of a sensitive AC magnetometer using a resonant excitation coil for this purpose. The excitation coil fabricated from a Litz wire is connected to a capacitor network to reduce the impedance of the circuit efficiently. The high efficiency showed by the excitation coil enables investigation of MNP’s dynamics in the nonlinear magnetization region. We demonstrate the sensitivity of the developed system by measuring the harmonics distribution of multi-core iron oxide nanoparticles suspended in solutions with the iron concentration down to 300 ng/ml. We experimentally show that the first harmonic component is not entirely ‘transparent’ to the diamagnetic background of the carrier liquid compared to the higher harmonics. We also demonstrate the complex magnetization measurement of the iron oxide nanoparticles in solution and immobilized states from 3 Hz to 18 kHz. A highly sensitive exploration of MNPs’ dynamics can be expected using the developed AC magnetometer.
{"title":"A Sensitive AC Magnetometer using A Resonant Excitation Coil for Magnetic Fluid Characterization in Nonlinear Magnetization Region","authors":"M. M. Saari, Nazatul Sharreena Suhaimi, N. A. C. Lah, K. Sakai","doi":"10.1109/INTMAG.2018.8508784","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508784","url":null,"abstract":"In order to tailor the magnetic nanoparticles (MNPs) properties for intended applications, it is crucial to unravelling their fundamental dynamics with respect to excitation magnetic field. In this work, we report on the development of a sensitive AC magnetometer using a resonant excitation coil for this purpose. The excitation coil fabricated from a Litz wire is connected to a capacitor network to reduce the impedance of the circuit efficiently. The high efficiency showed by the excitation coil enables investigation of MNP’s dynamics in the nonlinear magnetization region. We demonstrate the sensitivity of the developed system by measuring the harmonics distribution of multi-core iron oxide nanoparticles suspended in solutions with the iron concentration down to 300 ng/ml. We experimentally show that the first harmonic component is not entirely ‘transparent’ to the diamagnetic background of the carrier liquid compared to the higher harmonics. We also demonstrate the complex magnetization measurement of the iron oxide nanoparticles in solution and immobilized states from 3 Hz to 18 kHz. A highly sensitive exploration of MNPs’ dynamics can be expected using the developed AC magnetometer.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"26 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86312033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508761
C. Custers, J. Jansen, E. Lomonova
In design and optimization of electrical machines, accurate models of the electromagnetic fields are important to predict the performance of the machine. The finite element method (FEM) is often used, because of its ability to produce accurate results when it is correctly utilized. However, the method can be demanding in terms of memory and relatively slow in terms of computation time. Therefore, semi-analytical models have been proposed over the years for increasingly complex structures in both 2D and 3D. One of the semi-analytical models is the harmonic modeling technique [1], [2], [3], which uses a Fourier bases to describe the solutions to electromagnetic field quantities. In many electromagnetic configurations, accurate results are obtained using a relatively low number of harmonics. However, for more complex structures, the number of harmonics has to be increased to retain accuracy. This leads to a proportional increase in the required memory. As a result, especially in 3D models, the advantage in terms of memory of the harmonic model in comparison to FEM is reducing. In this paper an alternative solving method for 3D harmonic models with position dependent material properties is presented. Using the scattering matrix approach, the memory required to obtain the solutions of the model is significantly reduced.
{"title":"Memory Efficient Harmonic Method for Electromagnetic Models Using Scattering Matrices.","authors":"C. Custers, J. Jansen, E. Lomonova","doi":"10.1109/INTMAG.2018.8508761","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508761","url":null,"abstract":"In design and optimization of electrical machines, accurate models of the electromagnetic fields are important to predict the performance of the machine. The finite element method (FEM) is often used, because of its ability to produce accurate results when it is correctly utilized. However, the method can be demanding in terms of memory and relatively slow in terms of computation time. Therefore, semi-analytical models have been proposed over the years for increasingly complex structures in both 2D and 3D. One of the semi-analytical models is the harmonic modeling technique [1], [2], [3], which uses a Fourier bases to describe the solutions to electromagnetic field quantities. In many electromagnetic configurations, accurate results are obtained using a relatively low number of harmonics. However, for more complex structures, the number of harmonics has to be increased to retain accuracy. This leads to a proportional increase in the required memory. As a result, especially in 3D models, the advantage in terms of memory of the harmonic model in comparison to FEM is reducing. In this paper an alternative solving method for 3D harmonic models with position dependent material properties is presented. Using the scattering matrix approach, the memory required to obtain the solutions of the model is significantly reduced.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"11 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76821547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-10-24DOI: 10.1109/INTMAG.2018.8508552
M. Curti, J. Jansen, E. Lomonova
The optimisation routines and the validation models for the Electrical Machines(EM) are often based on Finite Element Method (FEM) models. However, their computation time is manifestly high, and are often replaced by semi-analytical models, which approximate the essential performance of EM with reduced computational cost. Therefore, the trade-off between the model accuracy and the size of the problem leads to the appropriate choice of the modelling technique [1]. Recently, Spectral Element Method (SEM) which uses higher order mesh elements compared to FEM, has been implemented for EM [2]. The latter benefits from higher convergence rate, resulting in a smaller size of the problem. Therefore, SEM is considered a potential option for building low-cost EM models. However, complex EM geometries are challenging for any technique, limiting their accuracy by the high aspect ratio and shapes with sharp corners. Consequently, the performance analysis must be thoroughly checked before making the choice. In this paper, the performance analysis of both SEM and FEM is discussed. An analytical solution for the magnetic field is used for the reference which is generated by the Harmonic Model (HM) [3] using a finite number of harmonics.
{"title":"Convergence Analysis of SEM and FEM to an analytical field distribution in the airgap.","authors":"M. Curti, J. Jansen, E. Lomonova","doi":"10.1109/INTMAG.2018.8508552","DOIUrl":"https://doi.org/10.1109/INTMAG.2018.8508552","url":null,"abstract":"The optimisation routines and the validation models for the Electrical Machines(EM) are often based on Finite Element Method (FEM) models. However, their computation time is manifestly high, and are often replaced by semi-analytical models, which approximate the essential performance of EM with reduced computational cost. Therefore, the trade-off between the model accuracy and the size of the problem leads to the appropriate choice of the modelling technique [1]. Recently, Spectral Element Method (SEM) which uses higher order mesh elements compared to FEM, has been implemented for EM [2]. The latter benefits from higher convergence rate, resulting in a smaller size of the problem. Therefore, SEM is considered a potential option for building low-cost EM models. However, complex EM geometries are challenging for any technique, limiting their accuracy by the high aspect ratio and shapes with sharp corners. Consequently, the performance analysis must be thoroughly checked before making the choice. In this paper, the performance analysis of both SEM and FEM is discussed. An analytical solution for the magnetic field is used for the reference which is generated by the Harmonic Model (HM) [3] using a finite number of harmonics.","PeriodicalId":6571,"journal":{"name":"2018 IEEE International Magnetic Conference (INTERMAG)","volume":"4 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2018-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77863072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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