Measurement and analysis of common and differential modes conducted emissions generated by an AC/DC converter

Introduction. Rectifiers are the most important converters in a very wide field: the transport of electrical energy in direct current and in the applications of direct current motors. In most electrical and electronic systems, rectifiers are non-linear loads made up of diodes, therefore they are a source of harmonic pollution at a base frequency with a distorting line current signal that generates electromagnetic interference. There are two disturbance modes: common mode and differential mode. These disturbances caused by the rapid variation of current and voltage as a function of time due to the switching of active components, passive components such as inductors, capacitors, coupling, etc. The purpose of this work is to study the conducted emissions generated by a rectifier connected to the Line Impedance Stabilizing Network in an electric circuit. The determination of these disturbances is done for firstly both common and differential modes at high frequency, and secondly harmonics current, line current at low frequency. The novelty of the proposed work consists in presenting a study of disturbance generated by rectifiers using simulation and also experimental measurements at low and high frequencies in order to compare the results. Methods. For the study of the disturbances conducted by the diode bridge converter (rectifier), the sources of conducted electromagnetic disturbances were presented in the first time. Then, the common and differential modes were defined. This converter was studied by LTspice Software for simulation and also experimental measurements at low frequency for harmonics current and high frequencies for disturbances in common and differential modes. Results. All the simulations were performed using the LTspice software and the results obtained are validated by experimental measurements performed in the APELEC laboratory at the University of Sidi Bel-Abbes in Algeria. The obtained results of conducted emissions at high frequency and total harmonics distortion of current at low frequency are compared between simulation and experiment. Вступ. Випрямлячі є найважливішими перетворювачами у дуже широкій сфері застосування: передача електроенергії постійного струму та застосування двигунів постійного струму. У більшості електричних та електронних систем випрямлячі є нелінійними навантаженнями, що складаються з діодів, тому вони є джерелом гармонійних «забруднень» на базовій частоті зі спотворенням сигналу лінійного струму, що генерує електромагнітні завади. Існує два режими завад: загальний та диференціальний режим. Ці завади викликані швидкою зміною струму і напруги в залежності від часу через перемикання активних компонентів, пасивних компонентів, таких як котушки індуктивності, конденсатори, муфти та ін. Метою даної роботи є вивчення кондуктивних випромінювань, створюваних випрямлячем, під‘єднаним до мережі стабілізатора повного опору лінії в електричному колі. Визначення цих завад проводиться, по-перше, як для  загального, такі для диференціального режимів на високій частоті, а по-друге, для гармонічного струму, лінійного струму на низькій частоті. Новизна запропонованої роботи полягає у поданні дослідження завад, створюваних випрямлячами, з використанням моделювання, а також експериментальних вимірювань на низьких та високих частотах для порівняння результатів. Методи. Для дослідження завад, створюваних діодним мостовим перетворювачем (випрямлячем), вперше були представлені джерела електромагнітних завад, що виникають. Потім було визначено загальний та диференціальний режими. Цей перетворювач був вивчений програмним забезпеченням LTspice для моделювання, а також експериментальними вимірюваннями на низьких частотах для гармонійного струму та високих частот для завад у загальному та диференціальному режимах. Результати. Усі моделювання були виконані з використанням програмного забезпечення LTspice, а отримані результати підтверджені експериментальними вимірюваннями, проведеними в лабораторії APELEC в Університеті Сіді-Бель-Аббес в Алжирі. Отримані результати для кондуктивних завад на високій частоті та повних гармонічних спотворень струму на низькій частоті порівнюються стосовно моделювання та експерименту.

Experimental study of electromagnetic disturbances in common and differential modes in a circuit based on two DC/DC boost static converter in parallel

Introduction. An electronic control and closing control at the switch (MOSFET) will allow a parallel connection of two DC/DC boost converters. The reason for paralleling converters is to increase the efficiency of the power conversion process. This means that the overall power loss on the main switches is half the power loss on the main switch of a converter. It has been proven that DC-DC converters operating in parallel have different dynamics than a single converter. In this paper, the study is based on a system of two boost converters operating in parallel under current mode control. Although two converters operating in parallel increase the efficiency of the system, if the control parameters are not chosen correctly, the system becomes unstable and starts to oscillate. Purpose of this work is to present the analysis of high frequency electromagnetic disturbances caused by the switching of power switches in DC/DC boost static converters mounted in parallel in the presence of cables. We will study the improvement of the electromagnetic compatibility performances which can be brought by the choice of a static converters for industrial use. Methods. For the study of the path of the currents in common mode and in differential mode, it was possible to evaluate experimentally the electromagnetic compatibility impact in common mode and in differential mode of two boost converters connected in parallel in an electric circuit in connection with the source through a printed circuit board of connection between the source and the load, while using the two basic methods, namely the prediction of the conducted electromagnetic interference, the temporal simulation and the frequency simulation. Results. All the obtained results are validated by experimental measurements carried out at the Djillali Liabes University Sidi-Bel-Abbes in Laboratory of Applications of Plasma, Electrostatics and Electromagnetic Compatibility (APELEC). The experimental results obtained in common mode and in differential mode at low, medium and high frequencies are compared between the parallel boost test with and without electromagnetic compatibility filter

New ELISA for B Cell-Activating Factor

Item does not contain fulltextWorkshop Theory and Methodology - 26th ISAGA Conference, 18 juli 1995Valencia, Spain : [S.n.]24 p

Selecting the most suitable classification algorithm for supporting assistive technology adoption for people with dementia: A multicriteria framework

The number of people with dementia (PwD) is increasing dramatically. PwD exhibit impairments of reasoning, memory, and thought that require some form of self‐management intervention to support the completion of everyday activities while maintaining a level of independence. To address this need, efforts have been directed to the development of assistive technology solutions, which may provide an opportunity to alleviate the burden faced by the PwD and their carers. Nevertheless, uptake of such solutions has been limited. It is therefore necessary to use classifiers to discriminate between adopters and nonadopters of these technologies in order to avoid cost overruns and potential negative effects on quality of life. As multiple classification algorithms have been developed, choosing the most suitable classifier has become a critical step in technology adoption. To select the most appropriate classifier, a set of criteria from various domains need to be taken into account by decision makers. In addition, it is crucial to define the most appropriate multicriteria decision‐making approach for the modelling of technology adoption. Considering the above‐mentioned aspects, this paper presents the integration of a five‐phase methodology based on the Fuzzy Analytic Hierarchy Process and the Technique for Order of Preference by Similarity to Ideal Solution to determine the most suitable classifier for supporting assistive technology adoption studies. Fuzzy Analytic Hierarchy Process is used to determine the relative weights of criteria and subcriteria under uncertainty and Technique for Order of Preference by Similarity to Ideal Solution is applied to rank the classifier alternatives. A case study considering a mobile‐based self‐management and reminding solution for PwD is described to validate the proposed approach. The results revealed that the best classifier was k‐nearest‐neighbour with a closeness coefficient of 0.804, and the most important criterion when selecting classifiers is scalability. The paper also discusses the strengths and weaknesses of each algorithm that should be addressed in future research

Improving case retrieval by enrichment of the domain ontology

International audienceOne way of processing case retrieval in a case-based reasoning CBR system is using an ontology in order to generalise the target problem in a progressive way, then adapting the source cases corresponding to the generalised target problem. This paper shows how enriching this ontology improves the retrieval and final results of the \cbr system. An existing ontology is enriched by automatically adding new classes that will refine the initial organisation of classes. The new classes come from a data mining process using formal concept analysis. Additional data about ontology classes are collected explicitly for this data mining process. The formal concepts generated by the process are introduced into the ontology as new classes. The new ontology, which is better structured, enables a more fine-grained generalisation of the target problem than the initial ontology. These principles are tested out within Taaable (http://taaable.fr), a CBR system that searches cooking recipes satisfying constraints given by a user, or adapts recipes by substituting certain ingredients for others. The ingredient ontology of Taaable has been enriched thanks to ingredient properties extracted from recipe texts

Half-Metallic Ferromagnetism in Double Perovskite Ca2CoMoO6 Compound : DFT + U Calculations

A systematic investigation on magnetism and spin-resolved electronic properties in double perovskite Ca2CoMoO6 compound was performed by using the full-potential augmented plane wave plus local orbitals (APW+lo) method within the generalized gradient approximation (GGA-PBE) and GGA-PBE+U scheme. The stability of monoclinic phase (P2114) relative to the tetragonal (I487) and cubic (Fmm 225) phase is evaluated. We investigate the effect of Hubbard parameter Uon the ground-state structural and electronic properties of Ca2CoMoO6 compound. We found that the ferromagnetic ground state is the most stable magnetic configuration. The calculated spin-polarized band structures and densities of states indicate that the Ca2CoMoO6 compound is half-metallic (HM) and half-semiconductor (HSC) ferromagnetic (FM) semiconductor with a total magnetic moment of 6.0 using GGA-PBE and GGA-PBE+U, respectively. The Hubbard U parameter provides better description of the electronic structure. Using the Vampire code, an estimation of exchange couplings and magnetic Curie temperature is calculated. Further, our results regarding the magnetic properties of this compound reveal their ferromagnetic nature. The GGA-PBE+U approach provides better band gap results as compared to GGA-PBE approximation. These results imply that Ca2CoMoO6 could be a promising magnetic semiconductor for application in spintronic devices

Why and How Knowledge Discovery Can Be Useful for Solving Problems with CBR

International audienceIn this talk, we discuss and illustrate links existing between knowledge discovery in databases (KDD), knowledge representation and reasoning (KRR), and case-based reasoning (CBR). KDD techniques especially based on Formal Concept Analysis (FCA) are well formalized and allow the design of concept lattices from binary and complex data. These concept lattices provide a realistic basis for knowledge base organization and ontology engineering. More generally, they can be used for representing knowledge and reasoning in knowledge systems and CBR systems as well

IMPACT DES LONGUEURS DE CABLE SUR LES EMISSIONS CEM CONDUITES D’UN CONVERTISSEUR DC/DC

International audienceCet article présente l’analyse par une approche expérimentale de l’influence de la position d’un convertisseur DC/DC entre une source et une charge au regard des émissions CEM conduites mesurées sur la source. La distance totale entre la source et la charge est gardée constante, c’est donc la longueur des câbles source-convertisseur et convertisseur-charge qui est modifiée. L’impact du raccordement du blindage est également étudié. Les résultats expérimentaux sont analysés et justifiés à l’aide de schémas électriques simples