Y. Le Menach

Determination and utilization of the source field in 3D magnetostatic problems

In this paper we study different approaches to introduce the source terms due to the inductors crossed by a uniform current density J/sub 0/ in 3D FEM. Two equivalent methods are developed to decompose the current density J in the facet element space with divergence free close to J/sub 0/. This decomposition is used in the a-formulation without gauge condition. Moreover, from the flux facet the source field H/sub s/ can be calculated in the edge element space and introduced into the /spl phi/-formulation. As examples of applications we have studied a coil with a complex geometry and a iron core coil.

Numerical model to discretize source fields in the 3D finite element method

This communication presents a method to discretize electromagnetic source fields in the Whitney element spaces for static electromagnetic potential formulations. This method requires no finite element solution to calculate this source fields. It is based on the use of a facet or an edge tree. We will test it on electrokinetic, electrostatic and magnetostatic examples.

3-D Stochastic Spectral Finite-Element Method in Static Electromagnetism Using Vector Potential Formulation

Stochastic spectral finite-element method can be used to take into account some random aspects in the input data (material characteristic, source terms) involved in static electromagnetism problems. Similarly to the deterministic case, two potential formulations can be used in the stochastic case. The vector potential formulation applied to static problems is developed and compared to the scalar potential one, previously developed.

Teaching drive control using Energetic Macroscopic Representation - initiation level

The energetic macroscopic representation (EMR) has been developed in 2000 to develop control of systems with several drives. Since 2002 this graphical tool has been introduced to teach drive control in France, then Canada and Switzerland. The University of Lille proposes two drive control units for students in electrical engineering: initiation level and expert level unit. This first paper deals with the content of the initiation level unit and describes the simulation project of an electrical vehicle using EMR.

Adaptive Method for Non-Intrusive Spectral Projection—Application on a Stochastic Eddy Current NDT Problem

The Non-Intrusive Spectral Projection (NISP) method is widely used for uncertainty quantification in stochastic models. The determination of the expansion of the solution on the polynomial chaos requires the computation of multidimensional integrals. An automatic adaptive algorithm based on nested sparse grids has been developed to evaluate those integrals. The adapted algorithm takes into account the weight of each random variable with respect to the output of the model. To achieve that it constructs anisotropic sparse grid of the mean, leading to a reduction of the number of numerical simulations. Furthermore, the spectral form of the solution is explicitly identified from the constructed quadrature scheme. Numerical results obtained on an industrial application in NDT demonstrate the efficiency of the proposed method.

Source Field Computation in NDT Applications

Numerical modeling of nondestructive testing (NDT) by eddy currents has been applied for qualification of two monitoring devices. Experimental data have enabled us to validate reliable and relevant finite-element method models. The encountered difficulties due to geometry (size and topology), the nature of the control signal (weak flux differences), and the movement accounting have been successfully overcome by evaluating the A-phi and T-Omega dual formulations with appropriate source fields and applying classical method to suppress the mesh numerical error and choosing the well-known lock-step technique

Study of an Electromagnetic Gearbox Involving Two Permanent Magnet Synchronous Machines Using 3-D-FEM

Recently, magnetic gearboxes know a real interest. Due to the use of rare earth magnets, they reach high performances. However, their design is often issue from the mechanical gearbox one and then they do not offer any degree of freedom. In this paper, we propose an electromagnetic gearbox constituted of two electromagnetic structures, one fit inside the other. As each of both structures has its own electrical supply, this introduces two degrees of freedom. Thus, the system can ensure as well the gear operating than that of the clutch. First, the operating of the system is described and the electromagnetic structures introduced. Then, its behavior is studied using a numerical model based on 3-D-finite-element method (FEM). Different results given by 3-D analysis are presented.

Stochastic Nondestructive Testing Simulation: Sensitivity Analysis Applied to Material Properties in Clogging of Nuclear Powerplant Steam Generators

A nondestructive testing procedure is currently used to estimate the clogging of tube support plates in French nuclear powerplant steam generators. A stochastic approach has been applied to the finite-element electromagnetic field simulation to evaluate the impact of material properties uncertainties on the monitoring signal. The polynomial chaos expansion method makes it possible to easily derive the Sobol decomposition which measures how much the variability of each input parameter affects the model output.

Automatic Multi-GPU Code Generation Applied to Simulation of Electrical Machines

The electrical and electronic engineerings have used parallel programming to solve their large scale complex problems for performance reasons. However, as parallel programming requires a non-trivial distribution of tasks and data, developers find it hard to implement their applications effectively. Thus, in order to reduce design complexity, we propose an approach to generate code for hybrid architectures (e.g., CPU + GPU) using OpenCL, an open standard for parallel programming of heterogeneous systems. This approach is based on Model Driven Engineering (MDE) and the MARTE profile, standard proposed by Object Management Group (OMG). The aim is to provide resources to non-specialists in parallel programming to implement their applications. Moreover, thanks to model reuse ability, we can add/change functionalities and the target architecture. Consequently, this approach helps industries to achieve their time-to-market constraints which are confirmed here by experimental tests. Besides the software development at high-level abstractions, this approach aims to improve performance by using multi-GPU environments. A case study based on the Conjugate Gradient method gives clarity to our methodology.

Study of synchronous generator eccentricities using analytical approach and FEM

This paper deals with the study of rotor turbogenerator eccentricities using an analytical approach and FEM. First, we present the cases of eccentricities and the method, based on the measure of the flux density in the air-gap, used to detect the faults. Both models, the analytical approach and the numerical one are then introduced. Using these models, static, dynamic and combined eccentricities are studied at no load. The results obtained by both approaches are compared and the limits of the analytical model are underlined relatively to the effect of the non linearity of the magnetic material characteristic and the induced eddy currents.