MICRO CAPTEUR MAGNETIQUE DE MESURE DE COURANT ET TRAITEMENT INTEGRE

This thesis focuses on the current measurement from magnetic field measurement without using magnetic concentrator. A new current system ensuring good magnetic perturbation rejection has been realized. It consists to disposes one differential magnetic fluxgate sensor upon sections of U-shaped conductor. This conductor was crossed by the current to be measured. Using this system, we are reduced many problems of magnetic and mechanical misalignments acquired when using two magnetic sensors. Besides, using a single magnetic core permits to overcome the disparity between two magnetic sensors. This system has been studied theoretically and validated experimentally. The impacts of various factors of achievement have been studied by using analytical calculations, elements finite simulations and measurements. The integration of this current system permits the dissemination of current sensor.Les travaux décrits dans cette thèse portent sur la mesure de courant à partir de mesure de champ magnétique sans canalisation de flux. Une nouvelle structure de capteur de courant basée sur une mesure différentielle du champ magnétique a été réalisée. Elle consiste à disposer un seul capteur magnétique différentiel linéaire du type fluxgate au-dessus des sections d'un conducteur en forme U traversé par le courant à mesurer. Utilisant cette structure, nous avons pu améliorer la précision et assurer une bonne réjection des perturbations magnétiques extérieures. Cette structure a été étudiée théoriquement et validée expérimentalement. Les impacts de divers facteurs de réalisation ont été étudiés à l'aide de calculs analytiques, des simulations par éléments finis et des mesures. L'intégration de cette nouvelle structure faciliterait la dissémination de capteurs de courant

MICRO CAPTEUR MAGNETIQUE DE MESURE DE COURANT ET TRAITEMENT INTEGRE

This thesis focuses on the current measurement from magnetic field measurement without using magnetic concentrator. A new current system ensuring good magnetic perturbation rejection has been realized. It consists to disposes one differential magnetic fluxgate sensor upon sections of U-shaped conductor. This conductor was crossed by the current to be measured. Using this system, we are reduced many problems of magnetic and mechanical misalignments acquired when using two magnetic sensors. Besides, using a single magnetic core permits to overcome the disparity between two magnetic sensors. This system has been studied theoretically and validated experimentally. The impacts of various factors of achievement have been studied by using analytical calculations, elements finite simulations and measurements. The integration of this current system permits the dissemination of current sensor.Les travaux décrits dans cette thèse portent sur la mesure de courant à partir de mesure de champ magnétique sans canalisation de flux. Une nouvelle structure de capteur de courant basée sur une mesure différentielle du champ magnétique a été réalisée. Elle consiste à disposer un seul capteur magnétique différentiel linéaire du type fluxgate au-dessus des sections d'un conducteur en forme U traversé par le courant à mesurer. Utilisant cette structure, nous avons pu améliorer la précision et assurer une bonne réjection des perturbations magnétiques extérieures. Cette structure a été étudiée théoriquement et validée expérimentalement. Les impacts de divers facteurs de réalisation ont été étudiés à l'aide de calculs analytiques, des simulations par éléments finis et des mesures. L'intégration de cette nouvelle structure faciliterait la dissémination de capteurs de courant

A Simple and Accurate Magnetic Gradient Sensor Configuration Dedicated to Electrical Currents Measurements

International audienceThis paper deals with electrical current identification from stray magnetic field measurements. To satisfy industrial's needs, a new technology is emerging and can allow size and cost reductions of sensors. It consists in placing non-contact magnetic field sensors closes to conductors and deducing the currents' magnitude by inverting the Biot-Savart law. The theoretical study executed in this paper illustrates the advantage of the gradient measurements compared to the field measurement, especially for the rejection of homogeneous magnetic disturbance. It is showing also that the approach of magnetic gradient measurements greatly reduces non homogeneous magnetic disturbance. But, when implementing the practical application for the gradient measurement approach, many difficulties will be appearing; we will list it in the paper sections. Next, we will suppose a configuration solution able to subdue these difficulties; it is based on "round-trip" conductors and consists to laying the two magnetic sensors collinearly along the same axis above the conductor sections to apply gradient measurements. Afterwards, we will apply this configuration for a three-phase system by describing the matrix form, using known geometries and locations of magnetic sensors, and we will explain the manner in which to calculate the reconstruction of the currents which is done by solving the inverse problem. The "round-trip" configuration combined with a simple magnetic shielding and integrated technology can lead to the design of highly accurate and low-cost current sensors

About the Use of Magnetic Gradient Measurements Dedicated to the Identification of Electrical Currents

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A SIMPLE AND ACCURATE MAGNETIC GRADIENT SENSOR CONFIGURATION DEDICATED TO ELECTRICAL CURRENTS MEASUREMENTS

International audienceThis paper deals with electrical current identification from stray magnetic field measurements. A new layout for magnetic gradient measurements is emerging and it can lead to the design of highly accurate and low cost current sensors

Numerical Study of a Liquid Metal Heat Spreader for Power Semiconductor Devices

International audienceThis paper describes a new thermal management approach for cooling of power semiconductor devices. This new approach is based on a liquid metal fluid flow in order to spread the heat and evacuate it to the ambient. The work presented in this paper is considered as a first step to design and realize a liquid metal heat spreader (LMHS) for power electronics devices. In the first part of the paper, the geometry of a LMHS is described. In the second part, a fully multiphysics numerical study is presented. In order to demonstrate the advantage of the liquid metal heat spreader, a thermal performances comparison with a copper spreader (having the same external dimensions) is presented in the last part of this paper. First results show that the thermal resistance of the system could by reduced by about 40% using this new cooling solution

Magnetic microsystems Mag-MEMS: novel trends

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