76 research outputs found
Induction machine fault detection enhancement using a stator current high resolution spectrum
No full textFault detection in squirrel cage induction machines based on stator current spectrum has been widely investigated. Several high resolution spectral estimation techniques have been developed and used to detect induction machine abnormal operating conditions. In this paper, a modified version of MUSIC algorithm has been developed based on the faults characteristic frequencies. This method has been used to estimate the stator current spectrum. Then, an amplitude estimator has been proposed and a fault indicator has been derived for fault severity measurement. Simulated stator current data issued from a coupled electromagnetic circuits approach has been used to prove the appropriateness of the method for air gap eccentricity and broken rotor bars faults detection
Apports des techniques de traitement du signal paramétriques pour l'analyse des signaux électriques et les communications optiques cohérentes
No full textThis manuscript presents my research activities carried out over the past 12 years at the laboratories IRDL (formerlyLBMS) and Lab-STICC. First, it summarises my scientific contributions during the period 2008-2018 within the IRDL. These contributions essentially focus on two main topics : the monitoring of electrical machines and the monitoring of electrical signals in smart-grids.To address these topics, the originality of our contributions lies in the use of parametric signal processing techniques.Second, this manuscript describes the research activities conducted within the Lab-STICC since my integration in 2018. These activities focus on the design of digital algorithms for imperfection compensation in coherent optical communication systems. After reviewing our current works dealing with the use of parametric approaches for the compensation of widely linear impairments (laser impermanent, IQ imbalance and chromatic dispersion), this thesis emphasizes the benefit of using mixed parametric approaches / machine learning to jointly compensate linear and nonlinear impairments in optical communication systems.Ce mémoire résume mes activités de recherches menées ces 12 dernières années à l’IRDL puis au Lab-STICC. Dans un premier temps, il présente une synthèse des travaux réalisés au sein de l’IRDL sur la période 2008-2018. Ces travaux couvrent essentiellement deux problématiques : le diagnostic des machines électriques et la surveillance des réseaux électriques (smart-grid). Pour résoudre ces problématiques, l’originalité de nos travaux réside dans l’exploitation systématique de la structure signaux au moyen de techniques de traitement du signal paramétriques.Dans un second temps, ce mémoire présente les activités de recherches initiées au laboratoire Lab-STICC depuis mon intégration en 2018. Ces activités concernent la conception d’algorithmes pour la compensation des imperfections dans les chaines de communications optiques cohérentes. Après avoir listé nos travaux en cours portant sur l’utilisation des approches paramétriques pour la compensation des imperfections linéaires au senslarge (imperfections du laser, déséquilibre IQ et dispersion chromatique), ce mémoire insiste sur le potentiel des approches mixtes paramétriques / machine learning pour compenser conjointement les imperfections linéaires et non-linéaires de la chaine de communication
Interception des signaux issus de communications MIMO
No full textLes communications multi-antennes, désignées par l acronyme MIMO (Multiple-Input Multiple-Output), permettent d atteindre des débits et une qualité de transmission élevés en exploitant la diversité spatiale du canal de propagation. De part leurs performances, les systèmes MIMO sont au coeur des futurs standards de réseaux sans- fil et de téléphonie mobile et devraient occuper prochainement une place importante dans le canal hertzien. Cette thèse, intitulée Interception des signaux issus de communications MIMO , aborde ces systèmes dans le contexte non coopératif c est-à-dire lorsque le récepteur ne dispose d aucune information sur la configuration de l émetteur, le canal de propagation et sur le niveau de bruit. L étude se situe en aval des étapes de synchronisation et suppose que les échantillons reçus sont préalablement ramenés en bande de base et échantillonnés au rythme d un échantillon par symbole. Sous ces hypothèses, nous proposons plusieurs algorithmes pour identifier en aveugle les paramètres de l émetteur tels que le nombre d antennes, le codage spatio-temporel et la modulation. Les applications concernées sont variées et touchent aussi bien le domaine civil (développement de récepteurs MIMO auto-configurants) que le domaine militaire.Multiple-Input Multiple-Output (MIMO) communications improve the data rates and the robustness of a wireless link by using the spatial diversity of the propagation channel. Because of its high performances, MIMO systems are the catalyst for the next revolution in wireless systems and would play a key role for the development of future networks and cell phones standards. In this PhD thesis, we investigate the problem of the blind recognition of the MIMO parameters under a non-cooperative environment i.e. when the transmitter parameters, the propagation channel and the noise level are unknown at the receiver side: This context occurs in various civilian and military situations. Assuming that the synchronization has been previously performed, we propose new algorithms devoted to the blind recognition of the number of transmitter antennas, of the space-time coding and of the modulation.BREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF
Interception des signaux issus de communications MIMO
No full textMultiple-Input Multiple-Output (MIMO) communications improve the data rates and the robustness of a wireless link by using the spatial diversity of the propagation channel. Because of its high performances, MIMO systems are the catalyst for the next revolution in wireless systems and would play a key role for the development of future networks and cell phones standards. In this PhD thesis, we investigate the problem of the blind recognition of the MIMO parameters under a non-cooperative environment i.e. when the transmitter parameters, the propagation channel and the noise level are unknown at the receiver side. This context occurs in various civilian and military situations. Assuming that the synchronization has been previously performed, we propose new algorithms devoted to the blind recognition of the number of transmitter antennas, of the space-time coding and of the modulation.Les communications multi-antennes, désignées par l'acronyme MIMO (Multiple-Input Multiple-Output), permettent d'atteindre des débits et une qualité de transmission élevés en exploitant la diversité spatiale du canal de propagation. De part leurs performances, les systèmes MIMO sont au coeur des futurs standards de réseaux sans-fil et de téléphonie mobile et devraient occuper prochainement une place importante dans le canal hertzien. Cette thèse, intitulée "Interception des signaux issus de communications MIMO", aborde ces systèmes dans le contexte non coopératif c'est-à-dire lorsque le récepteur ne dispose d'aucune information sur la configuration de l'émetteur, le canal de propagation et sur le niveau de bruit. L'étude se situe en aval des étapes de synchronisation et suppose que les échantillons reçus sont préalablement ramenés en bande de base et échantillonnés au rythme d'un échantillon par symbole. Sous ces hypothèses, nous proposons plusieurs algorithmes pour identifier en aveugle les paramètres de l'émetteur tels que le nombre d'antennes, le codage spatio-temporel et la modulation. Les applications concernées sont variées et touchent aussi bien le domaine civil (développement de récepteurs MIMO auto-configurants) que le domaine militaire (guerre électronique)
An Improved Algorithm for Power System Fault Type Classification based on Least Square Phasor Estimation
No full textInternational audienc
Classification of three-phase power disturbances based on model order selection in smart grid applications
No full textInternational audienceThis paper deals with a new classification techniques for power quality analysis. Specifically, the proposed technique aims at discriminating between four classes, where each class depends on the number of non-zero symmetrical components. By reformulating the classification problem as a pure model order selection one, we propose a classifier based on Information Theoretical Criteria. It yields the highest statistical performances. The performances of this proposed classifier are evaluated using Monte Carlo simulations with synthetic three-phase signals. Simulation results illustrate the effectiveness of the proposed classifier for power quality disturbances classification
A Spatialised Sound environment Synthesizer
No full textInternational audienceThe synthesis of spatialised sound environment is a mean to increase the "sense of presence" of a listener in a virtual environment. We define sound environment synthesis as the audio synthesis of sounds other than speech or music and which contribute to the ambience of the sound scene. This paper first proposes a classification of sounds, and a state of the art in sound synthesis and spatialisation. Then the architecture of an interactive spatialised sound environment synthesizer is described. This work is part of a more general research framework which aim is to evaluate the contribution of 3D sound in terms of realism, immersion, pleasure, etc, in different applications such as virtual reality, telecommunications, simulators, music..
Frequency and Phasor Estimations in Three-Phase Systems: Maximum Likelihood Algorithms and Theoretical Performance
No full textInternational audienc
Bearing Fault Detection in DFIG-Based Wind Turbines Using the First Intrinsic Mode Function
No full textWind energy conversion systems have become a focal point in the research of renewable energy sources. In order to make the DFIG-based wind turbines so competitive as the classical electric power stations it is important to reduce the operational and maintenance costs by continuously monitoring the condition of these systems. This paper provides a method for bearing fault detection in DFIG-based wind turbines. The proposed method uses the first Intrinsic Mode Function (IMF) of the stator current signal. After extracting the first IMF, amplitude-demodulation is performed to reveal a generator bearing fault. Experimental results show that the proposed method significantly improves the result of classical amplitude-demodulation techniques for failure detection
Voltage Sags Estimation in Three-Phase Systems using Unconditional Maximum Likelihood Estimation
No full textTypo Correction on equation (19).International audienceThis paper focuses on the estimation of voltage sags in three-phase power systems. Specifically, it proposes a new approach for estimating the amplitude and phase angle of the sag based on the Unconditional Maximum Likelihood technique. As opposed to other techniques, this approach is well suited for signals with amplitude and/or phase modulation such as those encountered in smart grid applications. Simulation and experimental results illustrate the effectiveness of the proposed approach
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