Elektromagnetsko modeliranje struktura žica-uzemljenje korištenjem pristupa temeljenog na modeliranju transmisijskih linija

A multi-conductor transmission lines-based approach is developed to model electromagnetic coupling of wires above metallic structures. With this approach, global impedances and local distributions are accessible. According the frequency range and the geometry of the studied structures, it is possible to only take into account well-chosen parts. In that case, the shading concept provides an efficient way to determine which part is sufficient, thereby allowing reduction in model size. Global quantities results are validated against measurements, and local ones by theoretical knowledge. This work is usefulness in both the nomadic applications (automotive and aeronautic wiring ...) and the usual electrical applications (home and industrial wiring).Pristup temeljen na visevodičkim transmisijskim linijama razvijen je kako bi se modelirala elektromagnetska sprega žica iznad metalnih struktura. Uz takav pristup, dostupne su i globalne impedancije i lokalne distribucije. S obzirom na raspon frekvencija i geometriju promatranih struktura moguće je uzeti u obzir samo dobro odabrane dijelove. U tom slučaju koncept zasjenjenja pruža učinkovit način za određivanje koji su dijelovi dostatni i tako se omogućuje smanjenje veličine modela. Rezultati globalnih veličina vrednovani su prema mjerenjima, a lokalne veličine prema teoretskom znanju. Ovaj je rad koristan u specifičnim aplikacijama (automobilsko i aeronautičko ožičenje...) i klasičnim električnim aplikacijama (kućanstvo i industrija)

Eddy Current Characterization Using Robust Meta-Heuristic Algorithms for LS-SVM Hyper-Parameters Optimization

International audienceThis paper presents the use of the Least Square Support Vector Machines (LS-SVM) technique, combined with the Finite Element Method (FEM), to characterize small cracks in order to get a fast non-destructive inspection. The LS-SVM is a statistical learning method that has good generalization capability and learning performance. LS-SVM trained model is proposed to predict crack sizing using experimental signals acquired from an Eddy Current (EC) sensor. The FEM is used to create the data set required to train this model. The performance of LS-SVM model depends on a careful setting of its associated hyper-parameters. Different tuning techniques for optimizing the LS-SVM hyper-parameters are studied: Electromagnetism-Like Mechanism (EM), Opposition Based Electromagnetism-Like Mechanism (OBEM) and Teaching Learning Based Optimization (TLBO). Results show that TLBO algorithm provides a good compromise between accuracy and computational cost

The combination of adaptive database SDM and multi-output SVM for eddy current testing

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Ridge Polynomial Neural Network for Non-destructive Eddy Current Evaluation

978-3-642-16224-4Motivated by the slow learning properties of Multi-Layer Perceptrons (MLP) which utilize computationally intensive training algorithms, such as the backpropagation learning algorithm, and can get trapped in local minima, this work deals with ridge Polynomial Neural Networks (RPNN), which maintain fast learning properties and powerful mapping capabilities of single layer High Order Neural Networks (HONN). The RPNN is constructed from a number of increasing orders of Pi-Sigma units, which are used to solving inverse problems in electromagnetic Non-Destructive Evaluation (NDE). The mentioned inverse problems were solved using Artificial Neural Network (ANN) for building polynomial functions to approximate the correlation between searched parameters and field distribution over the surface. The inversion methodology combines the RPNN network and the Finite Element Method (FEM). The RPNN are used as inverse models. FEM allows the generation of the data sets required by the RPNN parameter adjustment. A data set is constituted of input (normalized impedance, frequency) and output (lift-off and conductivity) pairs. In particular, this paper investigates a method for measurement the lift-off and the electrical conductivity of conductive workpiece. The results show the applicability of RPNN to solve non-destructive eddy current problems instead of using traditional iterative inversion methods which can be very time-consuming. RPNN results clearly demonstrate that the network generate higher profit returns with fast convergence on various noisy NDE signals

New approach to study HTS bulk behavior for a fully superconducting motor design

The originality of this work is to applied Amperian Approach for modelling HTS bulk especially in electrical motor applications. This approach has proven its efficiency in electrical materials having a constant conductivity. For HTS materials, the resistivity change brutally and have a non linear comportment through any external magnetic field variations. To success the modelisation, we have to create an iterative procedure. All simulation steps are based on the power law model for computing resistivity and current densities adding the fixed point method for non linear iterations. The majority of our results concern the current densities in the HTS bulk rotor with different critical currents constatations under mgnetic field created by three phase coils of the proposed superconducting synchronous motor (SSM) prototype. Some results are consolidated by numerical way using flux 2D software

Eddy current characterization of small cracks using least square support vector machine

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Experimental study of controlled active neutralization of polypropylene films

International audienceAC corona discharge is widely employed for neutralizing the electric charges at the surface of insulating bodies: films, plates, granules, etc. If uncontrolled, this active neutralization process is accompanied by the persistence of a residual charge at the surface of the treated bodies. The aim of this present work is to demonstrate experimentally the efficiency of the controlled active neutralization using AC corona generated in a triode-type electrode configuration, with the grid connected to the ground. The experimental study was carried out on DC corona charged polypropylene films that were neutralized by a sinusoidal corona discharge at industrial frequency (50 Hz). The distribution of the electric potential at the surface of the charged and neutralized samples were measured by a non-contact electrostatic voltmeter. The factors under study were: the amplitude of the AC voltage applied to the corona electrode of the triode system, the duration of exposure to the corona discharge, the scanning speed, and the spacing between the grid and sample. The experimental results obtained show that the neutralization rate is close to 100%, i.e. the electric potential profiles obtained at the surface exposed to AC corona discharge show the absence of the residual charge. The results show that the efficiency of the controlled active neutralization depends on the energy that the AC corona discharge imparts to the charged samples, and that affects the trapped bulk charge

An approach based on ANFIS and input selection procedure for microwave characterization of dielectric materials

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