Switching-Cell Arrays - An Alternative Design Approach in Power Conversion

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThe conventional design of voltage-source power converters is based on a two-level half-bridge configuration and the selection of power devices designed to meet the full application specifications (voltage, current, etc.). This leads to the need to design and optimize a large number of different devices and their ancillary circuitry and prevents taking advantage from scale economies. This paper proposes a paradigm shift in the design of power converters through the use of a novel configurable device consisting on a matrix arrangement of highly-optimized switching cells at a single voltage class. Each switching cell consists of a controlled switch with antiparallel diode together with a self-powered gate driver. By properly interconnecting the switching cells, the switching cell array (SCA) can be configured as a multilevel active-clamped leg with different number of levels. Thus, the SCA presents adjustable voltage and current ratings, according to the selected configuration. For maximum compactness, the SCA can be conceived to be only configurable by the device manufacturer upon the customer needs. For minimum cost, it can also be conceived to be configurable by the customer, leading to field-configurable SCAs. Experimental results of a 6x3 field-configurable SCA are provided to illustrate and validate this design approach.Peer ReviewedPostprint (author's final draft

The IACOB spectroscopic database of Galactic OB stars

We present the IACOB spectroscopic database, the largest homogeneous database of high-resolution, high signal-to-noise ratio spectra of Northern Galactic OB-type stars compiled up to date. The spectra were obtained with the FIES spectrograph attached to the Nordic Optical Telescope. We briefly summarize the main characeristics and present status of the IACOB, first scientific results, and some future plans for its extension and scientific exploitation.Comment: 2 pages. Poster contribution to the proceedings of the IAU272 "Active OB stars: structure, evolution, mass loss and critical limits

Medio ambiente y comercio internacional: El caso de los productos derivados de las focas

Tradicionalmente la protección del medio ambiente no ha supuesto una preocupación en el seno de las organizaciones comerciales internacionales. Por lo general, las medidas comerciales que buscaban salvaguardar el medio ambiente eran consideradas como tapaderas para restringir el comercio. En esta situación, ha surgido un confl icto comercial que enfrenta a Canadá con la Unión Europea a raíz del veto de esta última a la importación de productos de foca. La solución dada por el Grupo Especial de la OMC a esta controversia ha supuesto un importante avance en materia de protección del medio ambiente en el sistema comercial internacional, ya que permite que el artículo XX del GATT de 1994 sea aplicado de forma que pueda justifi car una restricción comercial en base a consideraciones morales de bienestar animalTraditionally, environmental protection has not led to a concern within the international trade organizations. Usually, the commercial measures that were seeking to safeguard the environment were considered to be covers to restrict the trade. This situation has arisen a trade confl ict between Canada and the European Union after the latter’s veto on the import of seal products. The solution given by the Panel of the WTO to this controversy was a major breakthrough in the fi eld of environmental protection in the international trading system, since it lets Article XX of the GATT 1994 to be applied so that trade restriction is justifi ed on moral considerations of animal welfar

La misma piedra

Rol de los ferocariles y caminos en la guera actual europeaComo debe completarse la red ferroviaria chilena  

Adaptive Multi-Pattern Fast Block-Matching Algorithm Based on Motion Classification Techniques

Motion estimation is the most time-consuming subsystem in a video codec. Thus, more efficient methods of motion estimation should be investigated. Real video sequences usually exhibit a wide-range of motion content as well as different degrees of detail, which become particularly difficult to manage by typical block-matching algorithms. Recent developments in the area of motion estimation have focused on the adaptation to video contents. Adaptive thresholds and multi-pattern search algorithms have shown to achieve good performance when they success to adjust to motion characteristics. This paper proposes an adaptive algorithm, called MCS, that makes use of an especially tailored classifier that detects some motion cues and chooses the search pattern that best fits to them. Specifically, a hierarchical structure of binary linear classifiers is proposed. Our experimental results show that MCS notably reduces the computational cost with respect to an state-of-the-art method while maintaining the qualityPublicad

La protección de la salud en el marco de la Administración Penitenciaria

En este trabajo se hace una aproximación a las condiciones del encarcelamiento en España y, de un modo más concreto, a la protección de la salud de los internos. La pena privativa de libertad se configura como la "pena reina" del sistema de justicia criminal. Por ello, es necesaria una respuesta por parte del Estado para garantizar los intereses de los interno

Three essays on economic dynamics

This Ph.D. dissertation is composed of three chapters, in which several dynamical aspects about several economic problems are analyzed. In the first chapter, entitled “Dynamical Stability in Repeated Games”, we propose a definition of dynamic stability that can be applied to repeated games. For this purpose, we extend the traditional theory by extending the infinite repetition of the stage game not only towards the future, but also towards the past. This allows the existence of stationary strategies and hence the possibility of dynamic stability. In the second chapter, entitled “On the Role of Educational Subsidies” we develop an overlapping generations model, and we analyze its properties concerning the steady state and the transitional dynamics. We also calibrate the model with data on several European countries, and we find that the optimal distribution of public expenses between research and development and educational subsidies should be changed towards the former in a majority of countries. Finally, in the chapter entitled “Inflationary Effects of a Monetary Union” we develop a model that formalizes the Balassa-Samuelson effect, and we analyze its existence both in economies with independent monetary policy and in economies belonging to a monetary union. We find that this effect should only appear in countries inside a monetary union. For countries with independent monetary policy, the sign of the effect is the opposite. We also analyze the effects of an enlargement concerning fast growing countries. We find that both the average inflation rate of the Union and the inflation rate of the old members would be reduced, whereas there are two opposite effects for the new countries: the change towards a less relaxed monetary policy and a money attraction effect. We find that for certain countries of a hypothetical enlargement of the Euro zone, the former effect dominates, so the inflation rate of the new members would also be reduced. ______________________________________________________________________________________________________________________________________________________Esta tesis doctoral se compone de tres capítulos, en los que se analizan diversos aspectos dinámicos de varios problemas económicos. En el primer capítulo, titulado “Estabilidad Dinámica en Juegos Repetidos” se propone una definición de estabilidad dinámica que puede aplicarse a los juegos repetidos. Se amplía para ello la teoría tradicional extendiendo la repetición del juego de etapa no sólo infinitamente hacia el futuro, sino también hacia el pasado, lo que permite la existencia de estrategias estacionarias y por tanto la posibilidad de estabilidad dinámica. En el segundo, titulado “El Papel de los Subsidios a la Educación” se desarrolla un modelo de generaciones solapadas, y se analizan las propiedades tanto de su estado estacionario como de su dinámica de transición. Además, se realiza una calibración del modelo con datos de diversos países europeos, y se encuentra que la composición óptima de gasto público entre investigación y desarrollo y subsidios educativos debería reestructurarse a favor del primer concepto en la mayoría de los países. Finalmente, en el capítulo titulado “Efectos Inflacionarios de una Unión Monetaria” se desarrolla un sencillo modelo que formaliza el efecto Balassa-Samuelson, y se analiza su posible aparición tanto en economías con política monetaria independiente como en aquéllos pertenecientes a una unión monetaria. Se encuentra que este efecto sólo debería ser observable en países en una unión monetaria, siendo de signo contrario al esperado en los países con política monetaria independiente. Además, se analizan los efectos de una ampliación con países de alto crecimiento, encontrándose que tanto la inflación media de la Unión como la particular de sus antiguos miembros se reduciría, mientras que sobre los países nuevos hay dos efectos contrapuestos: el cambio hacia una política monetaria más restrictiva y un efecto de atracción de dinero. Se encuentra que para los países de una hipotética ampliación de la zona Euro, el primer efecto suele dominar, por lo que también se reduciría la inflación de los nuevos miembros