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Co-simulation of Electromagnetic Transients and Phasor Models: a Relaxation Approach Plumier, Frédéric ; ; Geuzaine, Christophe et al in IEEE Transactions on Power Delivery (in press) Co-simulation opens new opportunities to combine mature ElectroMagnetic Transients (EMT) and Phasor-Mode (PM) solvers, and take advantage of their respective high accuracy and execution speed. In this ... [more ▼] Co-simulation opens new opportunities to combine mature ElectroMagnetic Transients (EMT) and Phasor-Mode (PM) solvers, and take advantage of their respective high accuracy and execution speed. In this paper, a relaxation approach is presented, iterating between an EMT and a PM solver. This entails interpolating over time the phasors of the PM simulation, extracting phasors from the time evolutions of the EMT simulation, and representing each sub-system by a proper multiport equivalent when simulating the other sub-system. Various equivalents are reviewed and compared in terms of convergence of the PM-EMT iterations. The paper also considers the update with frequency of the Thévenin impedances involved in the EMT simulation, the possibility to compute the EMT solution only once per time step, and the acceleration of convergence through a prediction over time of the boundary variables. Results are presented on a 74-bus, 23-machine test system, split into one EMT and one PM sub-system with several interface buses. [less ▲] Detailed reference viewed: 78 (7 ULg)Efficient Computation of the Extrema of Algebraic Quality Measures for Curvilinear Finite Elements Johnen, Amaury ; Geuzaine, Christophe ; Conference (2016, June) The development of high-order computational methods for solving partial differential equations on unstructured grids has been underway for many years. Such methods critically depend on the availability of ... [more ▼] The development of high-order computational methods for solving partial differential equations on unstructured grids has been underway for many years. Such methods critically depend on the availability of high-quality curvilinear meshes, as one bad element can degrade the solution in the whole domain. The usual way of generating curved meshes is to first generate a (high-quality) straight-sided mesh. Then, mesh entities that are classified on the boundaries of the domain are curved. This operation introduces a "shape-distortion" that should be controlled. Quality measures allow to quantify to which point an element is well-shaped. They also provide tools to improve the quality of meshes through optimization. In this work we propose an efficient method to compute several quality measures for curved elements, based on the Jacobian of the mapping between the straight-sided elements and the curved ones. Contrary to the approach presented in "A. Gargallo-Peiró, X. Roca, J. Peraire, and J. Sarrate. Distortion and quality measures for validating and generating high-order tetrahedral meshes. Engineering with Computers, pages 1–15, 2014.", which relies on an L2-norm over the elements, we compute the actual minimum and maximum of the local quality measure for each element. The method is an extension of previous works on the validity of those elements (A. Johnen et al., 2013). The key feature is that we can adaptively expand functions based on the Jacobian matrix and its determinant in terms of Bézier functions. Bézier functions have both properties of boundedness and positivity, which allow sharp computation of minimum or maximum of the interpolated functions. [less ▲] Detailed reference viewed: 32 (3 ULg)Coupling Reduced Order Models of Electrical Devices with Electrical Network Simulators Paquay, Yannick ; Bruls, Olivier ; Geuzaine, Christophe Speech/Talk (2016) Detailed reference viewed: 14 (2 ULg)Comparing Physics-Based and Automatic Model Order Reduction Techniques for Nonlinear Magnetostatic Systems Paquay, Yannick ; Jacques, Kevin ; Geuzaine, Christophe et al Poster (2016, April 12) Detailed reference viewed: 9 (2 ULg)Proper orthogonal decomposition versus Krylov subspace methods in reduced-order energy-converter models ; ; Geuzaine, Christophe et al Speech/Talk (2016) Detailed reference viewed: 12 (1 ULg)Reduced Order Model for Accounting for High Frequency Effects in Power Electronic Components Paquay, Yannick ; Geuzaine, Christophe ; et al in IEEE Transactions on Magnetics (2016) Detailed reference viewed: 49 (8 ULg)Nonlinear Interpolation on Manifold of Reduced Order Models in Magnetodynamic Problems Paquay, Yannick ; Bruls, Olivier ; Geuzaine, Christophe in IEEE Transactions on Magnetics (2016), 52(3), 1-4 Detailed reference viewed: 48 (18 ULg)Domain Decomposition Methods for Time-Harmonic Electromagnetic Waves with High Order Whitney Forms Marsic, Nicolas ; ; et al in IEEE Transactions on Magnetics (2016), 52(3), Classically, domain decomposition methods (DDM) for time-harmonic electromagnetic wave propagation problems make use of the standard, low order, Nédélec basis functions. This paper analyzes the ... [more ▼] Classically, domain decomposition methods (DDM) for time-harmonic electromagnetic wave propagation problems make use of the standard, low order, Nédélec basis functions. This paper analyzes the convergence rate of DDM when higher order finite elements are used for both volume and interface discretizations, in particular when different orders are used in the volume and on the interfaces. [less ▲] Detailed reference viewed: 20 (4 ULg)Model Order Reduction of Nonlinear Magnetodynamics with Interpolation on Grassmann Manifold Paquay, Yannick ; Bruls, Olivier ; Geuzaine, Christophe Poster (2015, November) Detailed reference viewed: 41 (8 ULg)Geometrical validity of curvilinear pyramidal finite elements Johnen, Amaury ; Geuzaine, Christophe in Journal of Computational Physics (2015), 299 Detailed reference viewed: 21 (3 ULg)Model Order Reduction of Nonlinear Magnetodynamics with Manifold Interpolation Paquay, Yannick ; Bruls, Olivier ; Geuzaine, Christophe Poster (2015, October) Detailed reference viewed: 35 (9 ULg)Sequential decision-making approach for quadrangular mesh generation Johnen, Amaury ; Ernst, Damien ; Geuzaine, Christophe in Engineering with Computers (2015), 31(4), 729-735 A new indirect quadrangular mesh generation algorithm which relies on sequential decision-making techniques to search for optimal triangle recombinations is presented. In contrast to the state-of-art ... [more ▼] A new indirect quadrangular mesh generation algorithm which relies on sequential decision-making techniques to search for optimal triangle recombinations is presented. In contrast to the state-of-art Blossom-quad algorithm, this new algorithm is a good candidate for addressing the 3D problem of recombining tetrahedra into hexahedra. [less ▲] Detailed reference viewed: 388 (70 ULg)Design Sensitivity Analysis for Shape Optimization of Nonlinear Magnetostatic Systems Kuci, Erin ; ; Duysinx, Pierre et al in Magnetics, IEEE Transactions on (Volume:PP , Issue: 99 ) (2015) The paper discusses the sensitivity analysis for the shape optimization of a nonlinear magnetostatic system, evaluated both by direct and adjoint approaches. The calculations rely on the Lie derivative ... [more ▼] The paper discusses the sensitivity analysis for the shape optimization of a nonlinear magnetostatic system, evaluated both by direct and adjoint approaches. The calculations rely on the Lie derivative concept of differential geometry where the flow is the velocity field associated with the modification of a geometrical parameter in the model. The resulting sensitivity formulas can be expressed naturally in a finite element setting through a volume integral in the layer of elements connected to the surface undergoing shape modification. The accuracy of the methodology is analyzed on a 2D model of an interior permanent magnet motor (IPM), and on a 3D model of a permanent magnet system. [less ▲] Detailed reference viewed: 28 (7 ULg)Direct and Adjoint Sensitivity Analysis of Nonlinear Magnetostatic System: Application to Shape Optimization of Electrical Machines Kuci, Erin ; Geuzaine, Christophe ; Dular, Patrick et al Conference (2015, June 07) Detailed reference viewed: 10 (1 ULg)Design Sensitivity Analysis for Shape Optimization of Nonlinear Magnetostatic Systems Kuci, Erin ; Duysinx, Pierre ; Dular, Patrick et al in Proceedings of COMPUMAG 2015 (2015, June) In this paper, a direct and an adjoint analytic sensitivity analysis for a nonlinear magnetostatic system is obtained, in the context of shape optimization for any design function. The calculations are ... [more ▼] In this paper, a direct and an adjoint analytic sensitivity analysis for a nonlinear magnetostatic system is obtained, in the context of shape optimization for any design function. The calculations are based on the material derivative concept of continuum mechanics. The resulting sensitivity formula can be expressed as either a volume integral or as a boundary integral along the interface where shape modification occurs. A method for the calculation of the design velocity field and mesh updating scheme is introduced as well. The accuracy of the methodology is analysed on an inductor system, suggesting that the volume integration technique should be preferred. All methods are freely available for further testing in the open source environment GetDP/Gmsh. [less ▲] Detailed reference viewed: 21 (6 ULg)Comparison of Nonlinear Domain Decomposition Schemes for Coupled Electromechanical Problems Halbach, Alexandre ; Dular, Patrick ; Geuzaine, Christophe in Proceedings of COMPUMAG 2015 (2015, June) The aim of this paper is to compare several domain decomposition schemes for nonlinear, coupled electromechanical problems. Both staggered and monolithic electrostatic/elastic formulations are combined ... [more ▼] The aim of this paper is to compare several domain decomposition schemes for nonlinear, coupled electromechanical problems. Both staggered and monolithic electrostatic/elastic formulations are combined with an overlapping domain decomposition method applied either to the uncoupled, linear staggered resolutions or to the monolithic nonlinear system. The influence of the elastic waves frequency, of the electrostatic potential and of the mesh on the convergence rate is investigated on a simple 2D model of a vibrating micromembrane array. [less ▲] Detailed reference viewed: 19 (4 ULg)Finite element models for studying the capacitive behaviour of wound components ; Dular, Patrick ; et al in Proceedings of COMPUMAG 2015 (2015, June) Finite element models of increasing accuracy are proposed for the study of the capacitive behaviour of wound magnetic components. Simple models, which are based on the classical assumption of a decoupling ... [more ▼] Finite element models of increasing accuracy are proposed for the study of the capacitive behaviour of wound magnetic components. Simple models, which are based on the classical assumption of a decoupling between electric and magnetic fields, are first described. Formulations which enable such a coupling are then presented. The models are tested on various coreless inductors, made of round conductors or copper sheets. The results are discussed and compared with experimental data measured with an impedance analyzer. [less ▲] Detailed reference viewed: 14 (1 ULg)Using a vector Jiles-Atherton hysteresis model for isotropic magnetic materials with the FEM, Newton-Raphson method and relaxation procedure ; ; et al in Proceedings of NUMELEC 2015 (2015, June) This paper deals with the use of a vector Jiles- Atherton hysteresis model included in 2D finite element modelling. The Newton-Raphson algorithm is used with a relaxtion procedure, which ensures the ... [more ▼] This paper deals with the use of a vector Jiles- Atherton hysteresis model included in 2D finite element modelling. The Newton-Raphson algorithm is used with a relaxtion procedure, which ensures the convergence in most of the cases. We have simulated a T-shaped magnetic circuit with rotating fields and then a three-phase transformer model. [less ▲] Detailed reference viewed: 28 (2 ULg)Nonlinear Interpolation on Manifold of Reduced Order Models in Magnetodynamic Problems Paquay, Yannick ; Bruls, Olivier ; Geuzaine, Christophe Poster (2015, June) Proper Orthogonal Decomposition (POD) is an efficient model order reduction technique for linear problems in computational sciences, recently gaining popularity in electromagnetics. However, its ... [more ▼] Proper Orthogonal Decomposition (POD) is an efficient model order reduction technique for linear problems in computational sciences, recently gaining popularity in electromagnetics. However, its efficiency has been shown to considerably degrade for nonlinear problems. In this paper, we propose a reduced order model for nonlinear magnetodynamic problems by combining POD with an interpolation on manifolds, which interpolates the reduced bases to efficiently construct the desired solution. [less ▲] Detailed reference viewed: 44 (12 ULg)Reduced Order Model for Accounting for High Frequency Effects in Power Electronic Components Paquay, Yannick ; Geuzaine, Christophe ; et al Poster (2015, June) This paper proposes a reduced-order model of power electronic components based on the proper orthogonal decomposition. Starting from a full-wave finite-element model and several snapshots/frequencies, the ... [more ▼] This paper proposes a reduced-order model of power electronic components based on the proper orthogonal decomposition. Starting from a full-wave finite-element model and several snapshots/frequencies, the reduced-order (RO) model is constructed. Local field values (e.g. magnetic flux density, electric current density, magnetic or electric field) and global quantities (e.g. characteristic complex impedance, joule losses) can be determined for the intermediate frequencies with a very low computational cost and high accuracy. Particular attention is paid to the choice of the most suitable snapshots by means of three different greedy algorithms, the performance of which is compared. We adopt an automatic greedy algorithm that depends only on the RO model. [less ▲] Detailed reference viewed: 34 (10 ULg) |
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