Hysteretic control of grid-side current for a single-phase LCL grid-connected voltage source converter

© 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper proposes a new approach to control the grid-side current of LCL-grid connected voltage source converters using hysteretic relay feedback controllers. The closed loop system is stabilized by designing a local feedback around the relay element. The compensator allows the use of relay feedback controllers by making the controlled plant almost strictly positive real. The article proposes the use of the locus of the perturbed relay system as analysis and design tool and studies orbital stability for several plant and controller conditions. The approach is validated by means of simulation testing.Postprint (author's final draft

8. Catecismes de química

Els catecismes són llibres que es caracteritzen per plantejar un corpus de doctrina en forma de preguntes i respostes. Aquest estil es va aplicar sovint a llibres per a l'ensenyament de la química al llarg del segle XIX. En aquesta secció es presenta una panoràmica dels llibres catequètics relacionats amb la química intentant situar-los en el context dels llibres d'altres camps que fan servir aquest estil, des de l'antiguitat fins als nostres dies.In general terms, catechisms are books for instruction in a doctrine based on a series of questions and answers. This format was often used in books for the teaching of chemistry in the 19th century. This issue of the Book Chest presents an overview of chemistry-related catechisms, seeking to place them in the wider context of the books in a diversity of fields that have used this literary style from ancient times to the present

Marvellous molecular shapes

A survey of a variety of interesting molecular shapes characterized mostly in the last two decades is presented. The selection of molecules shown is made based on their attractive three-dimensional structures (so often concealed by their usual two-dimensional structural formulae), the unusual coordination geometries of metal atoms, the subjective appreciation of how beautiful, funny or interesting a molecular shape is, or the sticky nature of arene rings at terphenyl groups and their effects on the molecular shapes of metal complexes

El Bagul dels llibres: 7. Química, dones i llibres

En aquest article, es comenten, des d'una perspectiva històrica, les diverses formes en què les dones i la química han interactuat a través dels llibres.The different ways in which women and chemistry have interacted through books are analyzed from a historical perspective

The personal income tax applied in the member states of European Union. The case of Spain.

In the Communication on "Tax policy in the European Union - Priorities for the years ahead" (COM/2001/260 of 23 May 2001), the Commission reiterated its belief that there is no need for an across the board harmonisation of Member States' direct tax systems. For tax policy, the Communication established, as a main priority, the need to address the concerns of individuals and businesses operating within the Internal Market by focusing on the elimination of tax obstacles to all forms of cross-border economic activity, in addition to continuing the fight against harmful tax competition. This approach was confirmed in the Communication "The contribution of taxation and customs policies to the Lisbon strategy" (COM/2005/532 of 25 October 2005) (European Commission, 2006). The Spanish Law No 35/2006, 28 th November of Personal Income Tax, reformed that tax. The long-term capital gains will be taxed at 18% (before 15%) ;the tax scale will be comprised of only 3 or 4 brackets (before 5) and the top marginal rate (before 45%) will be reduced; and some tax credits and allowances (acquisition of permanent home and contributions to pension funds for example) were readjusted in order to make them more accessible to low-income earners. The present paper makes a brief approach to the harmonisation in the European Union, explains the reform of the Spanish Personal Income Tax, introduces new figures and formulas never seen before at book of taxes, analyses the concept of the Spanish Personal Income Tax, studies the elements of this tax as the beneficiary, taxable person, territoriality, basis of assessment, exemptions, explains the basic mechanism of the tax, deductions, the taxable base, the tax rates, collections and examples. This paper is the result of three researches that the authors are carrying out at The Institute for Fiscal Studies, Ministry of Economy and Finance, University of CEU San Pablo, Madrid and University of Oviedo Spain from 2006 to 2008

El papel de la educación en la filosofía moral de David Hume

El presente artículo muestra cómo la crítica humeana a los fundamentos del racionalismo moral y a sus consecuencias en el terreno de las ideas educativas propició un cambio significativo en la comprensión de los objetivos de la educación moral que pasaron de buscar el perfeccionamiento de la agencia, a perseguir la perfección y el refinamiento de las capacidades del individuo como espectador y evaluador moral imparcial. Esta trasformación de la finalidad y del currículo de la educación moral será la solución que Hume ofrezca a los problemas de parcialidad derivados de la historicidad y la caducidad del general point of view como criterio último para el juicio moral. La exposición constante del educando a todas las formas históricas de la belleza, junto con la poesía, la literatura, el estudio de la historia y la filosofía, constituirán para Hume la base de esta revolución pedagógica

La conservación del poder en David Hume

This article argues that the origin of the political principles and categories that Hume sets as essential to the preservation of political power and its effective exercise can be traced into the division of political agent that occurs as a result of the institution of justice and government in the origin of society. Their different roles and different degrees of freedom will determine, since then, and through political action and its irreversibility, the categories and the fundamental problems that Hume´s political philosophy should answer. From that framework, the panoply of political power preservation principles that Hume exposes in the Essays will be analyzed as a reflection of that original event and its particular evolution