Vincent Mazauric

A methodology for the sizing and the optimization of an electromagnetic release

In this paper we present a multi modeling problem, and the design process that we manage to associate with it. In the first part, the different models are described. The reasons for such modeling are also exposed. Then the applied design process is detailed and justified.

An Energy Based Approach of Electromagnetism Applied to Adaptive Meshing and Error Criteria

In order to improve the finite-element modeling of macroscopic eddy currents (associated with motion and/or a time-varying electrical excitation), an original error criterion for adaptive meshing, based on a local power conservation, is proposed. Then, the importance of the order element in the error computation is investigated. Finally, the criterion is coupled to a ldquobubblerdquo mesh generator, and an adaptive meshing of a 2D induction heating case is performed.

Key features of the electricity production sector through long-term planning : the French case

We present a view of a long-term French electricity production sector with a MARKAL approach. The aim of MARKAL is to optimise energy systems in the long- mid- term with an explicit description of the technologies used. Using the example of French electricity supply, we will illustrate the tools potential and provide the necessary technical information for assessing the extent to which MARKAL models provide a good opportunity for helping industry leaders and decision-makers who are involved in the electricity sector to make energy strategy choices-at regional, national and international level

Coupling of an electrical arc model with FEM for vacuum interrupter designs

We present a model of a rotating arc by coupling a finite element method (FEM) and an arc model. A FEM is used to calculate magnetic field between electrodes taking into account the real current distribution in the contacts and in the arc; moreover, ferromagnetic effects and induced currents can be taken into account. A phenomenological arc model is used to predict the arc voltage, which depends on the local magnetic field and the arc length. This arc voltage is updated as the arc displaces itself across the contact surface. The information about arc voltage and local circuit equations is sufficient to find the velocity of the moving arc; hence this model seems more effective than models using Lorentz-forces to describe arc movement which need a priori knowledge about viscosity. This presented method seems to be a promising tool to describe the behavior of rotating arcs in vacuum circuit breakers.

Electric railgun 3D modeling: computation of eddy currents and Lorentz force

In order to arrive at a three dimensional computer simulation of the electric arc, the electric railgun has been adopted as a simple model. The projectile representing the arc is a solid conductor moving between two parallel electrodes supplied by direct current. To accurately describe the problem, a three dimensional formulation that takes into account the eddy currents and the velocity, is required. Within the finite element method, a formulation based on a current vector potential is adopted because it enforces the conservation of the current which is here the origin of the force acting on the projectile. The results show the influence of the velocity on the eddy currents as well as on the Lorentz force. Eddy currents are mostly located in the rails near the contact. While in the magnetostatic case, the Lorentz force acting on the projectile is in good agreement with hand calculations of the loop effect, the current density is strongly affected by the velocity of the projectile.

Long-term planning and the sustainable power system: A focus on flexibility needs and network reliability

Long-term planning models are useful to describe future energy and technology options and to analyze environmental issues. They propose solutions for meeting future energy consumption. Focusing on the electricity sector, we argue that in order to provide a more relevant assessment of the power supply system ahead we need to tackle both flexibility needs and network reliability.

An Energy-Compliant Magnetodynamic Error Criterion for Eddy-Current Calculations

In order to improve the finite element modeling of macroscopic eddy currents, a quadratic energy-based error criterion is obtained from a thermodynamic description of electromagnetism. Attention is first paid on the analytical derivation of the criterion in a general sense-i.e. without any assumption about the potential formulation and including possible body motion-especially to validate its relevance in 2D or 3D and to stress its independence from the formulation or the kind of application. Preliminary validation is given on a Thomsons effect device: As expected, the state functions provide the global convergence of the calculation within an iterative procedure whereas the conservation of the electromagnetic power is assessed locally to highlight the ill-checked elements.

An energy-based model for dynamic hysteresis

A new approach to face the problem of dynamic hysteresis and assess extra losses in soft magnetic materials is investigated. Thanks to a spatial averaging technique and a variational principle, a dedicated formulation is derived. It takes into account microscopic magnetization mechanisms and domain wall motion-induced Joule losses. Implementation within the finite element method is discussed, and calculations are carried out for a 2-D geometry. The model provides first-order low-pass filtering properties.

An energy-based formulation for dynamic hysteresis and extra-losses

This paper investigates a new approach to face the problem of dynamic hysteresis and extra-losses in soft magnetic materials. Thanks to a spatial averaging technique and a variational principle, a dedicated formulation is derived. It takes microscopic magnetization mechanisms and domain wall motion-induced Joule losses into account. Implementation with the finite element method is discussed and first simple two dimensions and three dimensions calculations are carried out. The method is shown to be suitable within the linear dynamic approximation and far from saturation, which only requires additional non linear properties and numerical methods

Magneto-dynamic formulation to solve capacitive effect problems in an axi-symmetrical coil

This paper presents a magneto-dynamic finite element formulation coupled with circuit equations using the time-integrated electric potential. This formulation at high frequency, including displacement currents, permits the study of electric-magnetic interactions in electric coils. The massive conductors in which eddy currents can develop are considered. This formulation can resolve the parasitic capacitive effect problems in massive components for an axi-symmetrical domain.