So far, various numerical models have been developed to simulate high temperature superconductor ... more So far, various numerical models have been developed to simulate high temperature superconductor in 3D. However, the lack of analytical solutions in the 3D case and the scarcity of experimental data make it difficult to evaluate the accuracy of the proposed models. In the present work, a benchmark on the 3D numerical modeling of a superconducting bulk is introduced. The problem is tackled by five independent teams using six different numerical models. After a detailed description of the models and their implementations, the results obtained are compared and discussed.
2017 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering (ISEF) Book of Abstracts, 2017
In this paper, a Mixed Method using the Finite Element (FEM) and the meshless Natural Element Met... more In this paper, a Mixed Method using the Finite Element (FEM) and the meshless Natural Element Method (NEM) is used to determine the magnetic flux distribution in magnetic circuit of an electrical machine. In this solution, the NEM is applied exclusively in the gap of the machine where the largest deformations of the mesh are expected when the movement occurs. Due the use of anti-periodic boundary conditions, only 1/4 of machine is modeled reducing the computational cost. The error estimator and computational time by using the FEM, the NEM and the mixed FEM-NEM are obtained and compared.
Les supraconducteurs sont capables de transporter des densites de courant bien superieures aux co... more Les supraconducteurs sont capables de transporter des densites de courant bien superieures aux conducteurs classiques et sont donc particulierement adaptes pour des cables fort courant compacts. Toutefois ils fonctionnent a de tres basses temperatures ce qui necessite le dimensionnement d'un systeme cryogenique. Pour estimer les pertes dans le cable, il convient d'etudier les differents mecanismes de pertes a l'interieur du cable supraconducteur. Les pertes AC doivent etre calculees avec precision. Le supraconducreur MgB 2 qui est aujourd'hui un serieux candidat pour ces applications est ainsi etudie. Un modele numerique a ete realise. Ce modele 3-D prend en compte les proprietes non lineaires du supraconducteur ainsi que les proprietes magnetiques des materiaux presents. Les pertes AC dans le conducteur ont ensuite ete calculees sous plusieurs logiciels bases sur differentes formulations pour valider les resultats obtenus
High Temperature Superconductors (HTS) are promising for applications requiring high power densit... more High Temperature Superconductors (HTS) are promising for applications requiring high power densities, such as superconducting electrical motors. Various approaches have been developed to model HTS, in particular for AC losses evaluation in thin wires and tapes. Indeed, AC losses are one of the key factors to size properly the cryogenic systems. In some applications, where the HTS materials are used as magnetic screens or as permanent magnets, such as in electrical motors, it is relevant to estimate properly the penetration of the magnetic field in order to optimize the magnetization processes and the integration of these materials in such systems. In previous works [1]–[3], analytical tools in 2D have been successfully developed for calculating the magnetic field distribution in different devices integrating HTS bulks by considering them as perfect diamagnetic materials, e.g. a superconducting electrical machine or an inductor with an iron core used for the pulsed field magnetizatio...
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 2017
In this paper, the interpolation functions behavior of the natural element method (NEM) and the f... more In this paper, the interpolation functions behavior of the natural element method (NEM) and the finite element method (FEM) are compared. It is discussed how the unknown in both methods affects the stiffness matrix and contributes to NEM better accuracy. The visibility criterion and the constrained NEM are also addressed, and a pseudoalgorithm is proposed to implement the constrained Voronoi diagram, which is the base for the constrained NEM. A complex heterogeneous magnetic problem is solved by both FEM and NEM methods and their solutions are compared. It is shown that for the same discretization, the number of contributions for NEM is in general bigger than those related to the FEM and better accuracy results for NEM.
So far, various numerical models have been developed to simulate high temperature superconductor ... more So far, various numerical models have been developed to simulate high temperature superconductor in 3D. However, the lack of analytical solutions in the 3D case and the scarcity of experimental data make it difficult to evaluate the accuracy of the proposed models. In the present work, a benchmark on the 3D numerical modeling of a superconducting bulk is introduced. The problem is tackled by five independent teams using six different numerical models. After a detailed description of the models and their implementations, the results obtained are compared and discussed.
2017 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering (ISEF) Book of Abstracts, 2017
In this paper, a Mixed Method using the Finite Element (FEM) and the meshless Natural Element Met... more In this paper, a Mixed Method using the Finite Element (FEM) and the meshless Natural Element Method (NEM) is used to determine the magnetic flux distribution in magnetic circuit of an electrical machine. In this solution, the NEM is applied exclusively in the gap of the machine where the largest deformations of the mesh are expected when the movement occurs. Due the use of anti-periodic boundary conditions, only 1/4 of machine is modeled reducing the computational cost. The error estimator and computational time by using the FEM, the NEM and the mixed FEM-NEM are obtained and compared.
Les supraconducteurs sont capables de transporter des densites de courant bien superieures aux co... more Les supraconducteurs sont capables de transporter des densites de courant bien superieures aux conducteurs classiques et sont donc particulierement adaptes pour des cables fort courant compacts. Toutefois ils fonctionnent a de tres basses temperatures ce qui necessite le dimensionnement d'un systeme cryogenique. Pour estimer les pertes dans le cable, il convient d'etudier les differents mecanismes de pertes a l'interieur du cable supraconducteur. Les pertes AC doivent etre calculees avec precision. Le supraconducreur MgB 2 qui est aujourd'hui un serieux candidat pour ces applications est ainsi etudie. Un modele numerique a ete realise. Ce modele 3-D prend en compte les proprietes non lineaires du supraconducteur ainsi que les proprietes magnetiques des materiaux presents. Les pertes AC dans le conducteur ont ensuite ete calculees sous plusieurs logiciels bases sur differentes formulations pour valider les resultats obtenus
High Temperature Superconductors (HTS) are promising for applications requiring high power densit... more High Temperature Superconductors (HTS) are promising for applications requiring high power densities, such as superconducting electrical motors. Various approaches have been developed to model HTS, in particular for AC losses evaluation in thin wires and tapes. Indeed, AC losses are one of the key factors to size properly the cryogenic systems. In some applications, where the HTS materials are used as magnetic screens or as permanent magnets, such as in electrical motors, it is relevant to estimate properly the penetration of the magnetic field in order to optimize the magnetization processes and the integration of these materials in such systems. In previous works [1]–[3], analytical tools in 2D have been successfully developed for calculating the magnetic field distribution in different devices integrating HTS bulks by considering them as perfect diamagnetic materials, e.g. a superconducting electrical machine or an inductor with an iron core used for the pulsed field magnetizatio...
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 2017
In this paper, the interpolation functions behavior of the natural element method (NEM) and the f... more In this paper, the interpolation functions behavior of the natural element method (NEM) and the finite element method (FEM) are compared. It is discussed how the unknown in both methods affects the stiffness matrix and contributes to NEM better accuracy. The visibility criterion and the constrained NEM are also addressed, and a pseudoalgorithm is proposed to implement the constrained Voronoi diagram, which is the base for the constrained NEM. A complex heterogeneous magnetic problem is solved by both FEM and NEM methods and their solutions are compared. It is shown that for the same discretization, the number of contributions for NEM is in general bigger than those related to the FEM and better accuracy results for NEM.
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Papers by Brahim Ramdane