New space vector modulation algorithms applied to multilevel converters with balanced DC-link voltage

This work presents a survey of new space vector modulation algorithms for high power voltage source multilevel converters. These techniques provide the nearest switching vectors sequence to the reference vector and calculates the on-state durations of the respective switching state vectors without involving trigonometric functions, look-up tables or coordinate system transformations which increase the computational load corresponding to the modulation of a multilevel converter. These algorithms drastically reduce the computational load maintained permitting the on-line computation of the switching sequence and the on-state durations of the respective switching state vectors. The on-state durations are reduced to a simple addition. In addition, the low computational cost of the proposed methods is always the same and it is independent of the number of levels of the converter. The algorithms have been satisfactorily implemented in very low-cost microcontrollers.Ministerio de Ciencia y Tecnología DPI 2001-308

A novel space-vector algorithm for multilevel converters based on geometrical considerations using a new sequence control technique

his paper presents a fast and simple space vector modulation algorithm for voltage source multilevel converters for calculating the switching times and the space vectors using simple geometrical considerations. This method provides the nearest switching vectors sequence to the reference vector and calculates the on-state durations of the respective switching state vectors without involving trigonometric functions, look-up tables or coordinate system transformations which increase the computational load corresponding to the modulation of a multilevel converter. The low computational cost of the proposed method is always the same and it is independent of the number of levels of the converter. In addition, a new switching sequence control technique is presented for reducing the ripple of the DC-link voltage approximately in 66%

Effective modulation algorithm for three-level converters

This paper presents an effective modulation algorithm (EMA) for high power voltage source three-level converter. This approach drastically reduces the computational load maintained, being substituted by decision making. This method permits the on-line computation of the switching sequence and the on-state durations of the respective switching state vectors corresponding to the modulation of a three-level inverter. Therefore stored information from a memory or a table is not necessary in EMA. The modulation method used in this work presents the advantage of eliminating the angle from the calculations. This modulation technique permits an economic and simply electronic implementation

Peninsular fibulae: elbow «sículas» or type «Monachil»? News and revision

Se estudia un amplio conjunto de fibulas de codo de las tradicionalmente denominadas «sículas», bajo nuestra nomenclatura de tipo «Monachil», que vienen a completar el panorama cada vez más conocido de este tipo de artilugios problemáticos y paradigmáticos del Bronce Final en la Península Ibérica. De nuevo, se profundiza en sus diferentes tipologías y cronologías, así como en su dispersión regional y posible autoctonía o aloctonía, con el fin de seguir incidiendo en la elaboración de un factible marco crono-cultural, en el que encuadrar mínimamente sus mal definidas formas y desarrollos. Con los datos actuales no es factible mantener un origen sículo para estas fíbulas en la Península Ibérica.We study a wide range of elbow fibulae, traditionally referred to as «sículas» in our Monachil nomenclature. This study will fulfill our knowledge of these problematic and paradigmatic devices in the Late Bronze in the Iberian Peninsula. The different typologies and chronologies are deeply analyzed, as well as their regional distribution, focusing on their native or foreign origin. Our aim is to build a chrono-cultural framework incorporating these fibulae. With the current information available, we cannot conclude that these Iberian fibulae have a Sicilian origin

Generalized analytical approach of the calculation of the harmonic effects of single phase multilevel PWM inverters

This paper introduces a generalized analytical approach for calculating the total harmonic distortion THD and its weighted value WTHD for multilevel PWM inverters. The calculation considers one single phase and it can apply to any number of levels of the inverter in general. Although the analysis is based on the assumption of a high number of pulses, the developed equations can also be applied for lower frequency ratios fs/f1. The analytical formulas require the characteristic parameters of the PWM only, which are the modulation factor m, the switching frequency fs, the fundamental frequency f1, the effective inductance L and the DC link voltage inverters with a number of levels N are considered. It must be noticed that some differences appear between the case of N odd and N even. Several parametric curves arc calculated to define the specifications of an inverter with N levels in order to fulfill the harmonic voltage recommendations trying to reduce the output signal filtering

An expert consensus report on the clinical use of the Vycross® hyaluronic acid VYC-25 L filler.

Background: The portfolio of hyaluronic acid (HA) fillers and the techniques of administration have evolved in recent years. The latest innovation in the Vycross® range was the introduction of VYC-25L (Juvéderm Volux®; Allergan plc), a first-in- class filler effective for chin and facial lower third remodeling. The aim here was to provide clinicians who are starting to use VYC-25L with key advice, and to standardize procedures so that optimal and predictable outcomes can be obtained. Methods: A multidisciplinary group of experts in esthetic medicine from Spain and Portugal reviewed the properties, treatment paradigms, administration techniques, and potential complications of VYC-25L, on the basis of which they drafted consensus recommendations for its clinical use. Results: The consensus panel provided specific recommendations focusing on the patient profile, dose, administration techniques, and the complications of VYC-25L and their management. The panel identified five different profiles of patients who may benefit from VYC-25L, and they drafted recommendations aimed to facilitate the treatment of these patients, namely, microgenia (women/men), masculinization (men), rejuvenation (women/men), facial laxity (women/men), and submental convexity (women/men). In terms of their safety, no specific recommendations were made beyond those established for other HA fillers. Conclusions: The evolution of esthetic medicine makes it necessary to update the clinical recommendations that guide patient assessment and treatment with the new HA fillers developed. The current consensus document addresses relevant issues related to the use of VYC-25L on different types of patient, in an attempt to standardize procedures and help specialists obtain predictable results.post-print806 K

Hacia una oferta integral de servicios para los editores de revistas de la Universitat Politècnica de Catalunya

Peer ReviewedPostprint (published version

Power-electronic systems for the grid integration of renewable energy sources: a survey

The use of distributed energy resources is increasingly being pursued as a supplement and an alternative to large conventional central power stations. The specification of a powerelectronic interface is subject to requirements related not only to the renewable energy source itself but also to its effects on the power-system operation, especially where the intermittent energy source constitutes a significant part of the total system capacity. In this paper, new trends in power electronics for the integration of wind and photovoltaic (PV) power generators are presented. A review of the appropriate storage-system technology used for the integration of intermittent renewable energy sources is also introduced. Discussions about common and future trends in renewable energy systems based on reliability and maturity of each technology are presented

Zoonoses and pets in domestic environments: risk communication

En las sociedades occidentales, la tenencia de mascotas en el hogar se incrementa anualmente debido a los beneficios emocionales, físicos y psíquicos que aportan. Junto a estos beneficios, debe considerarse también la existencia de diferentes enfermedades que pueden transmitirse desde los animales al resto de convivientes en el hogar, con especial importancia para aquellas personas pertenecientes a grupos de riesgo. El aparente desafío riesgo-beneficio que provoca la tenencia de mascotas deberá solventarse considerando el estado de salud de los miembros del hogar para la selección de la especie y la recomendación de medidas higiénicas y de manejo específicas. De forma general, el conocimiento y la preocupación de los propietarios por las zoonosis asociadas a sus mascotas son escasos, incluso en los hogares donde hay personas de alto riesgo. Además, las limitaciones en los procedimientos de comunicación con los diferentes profesionales sanitarios pueden ocasionar que las situaciones de riesgo pasen desapercibidas. Por todo ello, se impone la necesidad de establecer protocolos, tanto intra como interprofesionales, para proporcionar un adecuado flujo de información que asegure la comunicación con el propietario de acuerdo con las particularidades sanitarias de los convivientes de cada hogar.In occidental societies, the presence of pets in households increases year after year as a result of their beneficial effects on emotional, physical and psychological aspects. Along with these benefits, the existence of different diseases that can be transmitted from the animals to the rest of the members of the household must be taken into consideration, especially for those co-habitants who belong to the population at risk. This apparent challenge between the risks and benefits of pet ownership ought to be settled by taking into account the health status of the different members of the household in order to select the most convenient animal species as well as to determine the specific hygienic and management measures to apply. In general, the knowledge and concern of pet owners regarding the zoonoses associated to their pets are scarce, even when members of their household are considered as population at risk. In addition, the limitations affecting the communication procedures from the different health professionals may cause risk situations to pass by unnoticed. For this reason, it is necessary to establish interprofessional and intraprofessional protocols which ensure an adequate communication flow with pet owners depending on the particular health situation of their households