Design and control of a multicell interleaved converter for a hybrid photovoltaic-wind generation system

The solution for the generating energy derived from non-polluting sources configures a worldwide problem, which is undetermined, complex, and gradual; and certainly, passes through the diversification of the energetic matrix. Diversification means not only having different sources converted into useful energy, like the electricity, but also decentralizing the energy generation in order to fit with higher adequacy the demand, which is decentralized too. Distributed Generation proposes this sort of development but in order to increase its penetration several technical barriers must be overpassed. One of them is related to the conversion systems, which must be more flexible, modular, efficient and compatible with the different energy sources, since they are very specific for a certain area. The present study drives its efforts towards this direction, i.e. having a system with several inputs for combining different renewable energy sources into a single and efficient power converter for the grid connection. It focuses on the design and control of an 11.7 kW hybrid renewable generation system, which contains two parallel circuits of photovoltaic panels and a wind turbine. A multicell converter divided in two stages accomplishes the convertion: Generation Side Converter (GSC) and Mains Side Converter (MSC). Two boost converters responsible for the photovoltaic generation and a rectifier and a third boost, for the wind constitue the GSC. It allows the conversion to the fixed output DC voltage, controlling individually and performing the maximum power point tracking in each input. On the other side, the single-phase 4- cell MSC accomplishes the connection to the grid through an LCL filter. This filter uses an Intercell Transformer (ICT) in the first inductor for reducing the individual ripple generated by the swicthing. The MSC controls the DC-link voltage and, by doing that, it allows the power flow from the generation elements to the network

Numerical enhancement of a mesoscale model for large-eddy simulation of the wind over steep terrain

Mesoscale modelling of the atmospheric boundary layer has advanced significantly over the past decades, although there are still different numerical aspects that must be enhanced to achieve accurate wind simulations over steep topography. This has become a necessity since many applications, such as wind resource assessment, now require high fidelity results for viability analysis and decision-making. With the advent of high performance computing and more sophisticated software, the wind energy industry is increasingly interested in multiscale models based on combined configurations capable of yielding higher resolution results. The size of the modern wind farms now requires a multiscale analysis that allows the evaluation of the joint meso- and microscale processes triggered over complex topography. For this reason, mesoscale models with imbedded large-eddy simulation capabilities are well suited to become the next mainstream family of simulation toolkits for wind engineering. The Mesoscale Compressible Community (MC2) model, subject of this work, is a good example since it is employed as the kernel of the Wind Energy Simulation Toolkit (WEST), introduced by the Recherche en Prévision Numérique (RPN) group of Environment Canada. MC2 performs well for wind simulations over flat, gentle and moderate terrain slopes, which led the wind energy community to be confident enough on employing it to generate the Canadian Wind Atlas. However, as with other similar models, several numerical issues such as wind overestimation and distorted circulation patterns have been identified in recent years from orographic flow simulations in presence of steep slopes. Hence, wind resource assessment over high impact topography, such as the Rocky Mountains or the Niagara Escarpment, cannot be entirely reliable and needs a revaluation with enhanced multiscale modelling. By applying an eigenmode analysis, we have recognized the numerical instability and precisely measured the spurious noise problem, inherent of MC2’s classical three time-level semi-implicit (SI) scheme. With the appropriate redefinition of the prognostic thermodynamic variables, the SI time discretization, coupled with the semi-Lagrangian (SL) scheme, is now consistently structured in a way that it enables MC2 to solve the compressible non-hydrostatic Euler equations (EE) in a more stable and accurate fashion. MC2 is now able to perform wind simulations over steep slopes in the absence of time decentering, frequency filtering and other numerical damping mechanisms. Additionally, the climate-state classification of the statistical-dynamical downscaling (SDD) method is upgraded by including the Brunt-Väisälä frequency that accounts for the atmospheric thermal stratification effect on wind flow over topography. The present study provides a real orographic flow validation of these numerical enhancements in MC2, assessing their individual and combined contribution for an improved initialization and calculation of the surface wind in presence of high-impact terrain. Lastly, the metric tensor adaptation of MC2’s imbedded large-eddy simulation (LES) method, necessary for wind modelling over mountainous terrain, has been achieved preserving the enhanced numerical stability and accuracy. Test results indicate that the enhanced MC2-LES model reproduces efficiently the expected flow patterns, separation and recirculation zone over steep terrain, and yields accurate results comparable to those reported from experimental data or by other researchers who use numerical models with similar or more sophisticated turbulence closure schemes

Sobre la adquisición de metodologías de trabajo profesional y capacitación terminológica en el aula de traducción científico-técnica (francés-español): propuesta de elaboración de un diccionario de clase de apoyo a la enseñanza-aprendizaje de la traducción

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultd de Filosofía y Letras, Departamento de Filología Francesa, 14 de octubre de 201

Le rôle et la place de l'anglais de spécialité dans les petites annonces pour l'emploi en milieu scientifique

This dissertation focuses on English for Specific Purposes and more particularly on the terminology of scientific job advertisements discourse, an area still in pristine condition from a linguistic point of view. Job advertisements discourse is the sum of various discourses, i.e. human resources, advertising as well as a discourse which may be termed as "tourist" discourse and scientific discourse. Since the main purpose of advertisements is to advertise the company or the research laboratory, science discourse is minimized because it appears that this particular discourse fails to comply with the announcers’ ultimate aim. Once an analysis of human resources terms was done, a study was undertaken on scientific fields and a new terminology has been suggested, namely that of scientific hyperfields, fields and sub-fields. The analysis of scientific terms calls for a necessary distinction that has to be made between scientific terms and specialized terms. At last, the dissertation undertakes an analysis of linguistic and graphic means used in the advertising discourse.Cette étude en anglais de spécialité s’inscrit dans le domaine de la terminologie du discours des annonces pour l’emploi en milieu scientifique, domaine encore inexploré d’un point de vue linguistique. Le discours des annonces pour l’emploi est la somme de plusieurs discours, notamment discours des ressources humaines, discours publicitaire, discours qu’on peut appeler « touristique » et discours scientifique. Puisque le but primordial de l’annonce est de faire la publicité de l’entreprise ou du laboratoire de recherche, le discours scientifique y est réduit au minimum car il s’avère que ce discours ne peut se plier à la finalité et aux contraintes des annonceurs. Après une analyse des vocables des ressources humaines, un travail a été entrepris sur les domaines scientifiques concernés et une nouvelle terminologie a été proposée, articulée notamment autour de hyperdomaines, domaines et sous-domaines scientifiques. L’analyse des vocables scientifiques suggère une distinction nécessaire entre les vocables scientifiques et les termes spécialisés. Enfin, le travail se clôt par un examen des moyens linguistiques et graphiques mis en œuvre dans le discours publicitaire