Electric vehicle ultra-fast battery chargers: A boost for power system stability?

As a consequence of the exponential growth of the electric vehicle (EV) market, DC fast-charging infrastructure is being rapidly deployed all around the world. Ultra-fast charging (UFC) stations are starting to pose serious challenges to the electric power system operation, mostly due to their high peak power demand and unregulated discontinuous operation. To address these issues, local energy storage can be installed, ensuring a smoother grid power absorption profile and allowing to provide grid-supporting features. In this work, a control solution for the grid-side AC/DC converter of next-generation EV UFC stations is proposed. A virtual synchronous compensator (VSC) control algorithm is implemented, in order to lessen the impact of the charging station on the utility and to provide the full spectrum of grid ancillary services (i.e., frequency regulation, reactive power compensation, harmonic reduction, short circuit current generation, etc.). The proposed control strategy is verified experimentally on a downscaled 15 kVA three-phase inverter, emulating the grid front-end of the charging station

Admittance Model Identification of Inverters using Voltage Injection

The advancements in power electronics are leading to a growing number of electronic converters connected to the electric grid. Even though this enables a more efficient transformation and use of energy, the harmonic interaction between converters can cause instabilities in the network. Therefore, it is important to model the individual converters and their interconnection in an efficient way, in order to study the global stability of the system. A promising modelling strategy analytically derives the equivalent admittance of the converters. However, due to industrial secrecy issues, experimental identification methods are also necessary to obtain the converter equivalent admittance with a black-box approach. This paper analyses the experimental characterization of inverters using the voltage injection method. A detailed explanation of the theoretical background of this method and its practical implementation are provided

Fault-Tolerant Torque Controller Based on Adaptive Decoupled Multi-Stator Modeling for Multi-Three-Phase Induction Motor Drives

Among the multiphase solutions, multi-three-phase drives are becoming more and more widespread in practice as they can be modularly supplied by conventional three-phase inverters. The literature reports several control approaches to perform the torque regulation of multi-three-phase machines. Most of such solutions use the vector space decomposition (VSD) approach since it allows the control of a multi-three-phase machine using the conventional control schemes of three-phase drives, thus reducing the complexity of the control algorithm. However, this advantage is practically lost in the case of open-three-phase faults. Indeed, the postfault operation of the VSD-based drive schemes requires the implementation of additional control modules, often specifically designed for the machine under consideration. Therefore, this article aims to propose a novel control approach that allows using any control scheme developed for three-phase motors to perform the torque regulation of a multi-three-phase machine both in healthy and faulty operation. In this way, the previously mentioned drawbacks of the VSD-based control schemes in dealing with the faulty operation of the machine are avoided. Moreover, the simplicity of the control algorithm is always preserved, regardless of the machine's operating condition. The proposed solution has been experimentally validated through a 12-phase induction motor, rated 10 kW at 6000 r/min, using a quadruple-three-phase configuration of the stator winding

H-Bridge Converter as Basic Switching Topology Workbench in Power Electronics Teaching

This article deals with an effective power electronics learning setup based on a Full-Bridge converter used to teach electrical energy conversion experimentally. In the proposed learning by doing methodology, the hardware and the software are properly mixed in order to obtain an easy-to-use experimental learning environment. In this paper, the H-Bridge is the fundamental brick to build students’ knowledge on the main topics of power electronics converter circuit in different operative conditions. This H-Bridge comes with a reconfigurable output LCL to achieve several basic DC-DC powerconverters topologies. Converter current and voltage switching behavior can be investigated using the proposed setup. Furthermore, the friendly hardware and software set-up allows studying the converter modulation and control techniques of the different power electronics circuits

Experiencias en sensibilización de los sectores forestal y foresto industrial de Córdoba

Ponencia presentada en el 4° Congreso Forestal Argentino Latinoamericano: “Gestión forestal sostenible, futuro posible”. Misiones, Argentina, 23 al 28 de septiembre de 2013.Este trabajo aborda un estudio de caso sobre estrategias de sensibilización destinadas a los sectores forestal y foresto industrial de la provincia de Córdoba, Argentina. Las mismas se iniciaron en la década del noventa con una columna forestal en un diario de circulación masiva. Continuaron en búsqueda de nuevos horizontes y un feed-back más cercano a los actores forestales y foresto industriales, a través del desarrollo de jornadas, cursos, charlas, comisiones de trabajo, publicaciones, implementación de blogs, aula virtual y uso de red social facebook. Las acciones iniciaron en el año 1998, con los primeros pasos orientados a la implementación de una mejora, fluidez en la circulación de la información e iniciativas para consolidar un proceso de sensibilización sobre la importancia de la sustentabilidad y la competitividad en sistemas forestales-foresto industriales. Para su análisis se adoptó una metodología que permitió captar tanto el impacto de temáticas consideradas prioritarias como de las estrategias abordadas para lograr mayor fluidez en procesos de comunicación con miras a sensibilizar y consolidar pautas para el logro de una mejora de la competitividad de PyMES forestales y foresto industriales, así como de una gestión forestal sostenible. Las conclusiones destacan: i) la importancia de un mayor dinamismo, compromiso y participación ciudadana para consolidar consenso, concepciones, principios que propicien una mayor sustentabilidad y competitividad de los citados sectores ii) la necesidad de sensibilizar para promover un cambio tendiente a mejorar la cadena productiva forestal, su competitividad y sustentabilidad.This paper addresses a case study on strategies for raising awareness onforestry and forest industry problems in the province of Cordoba, Argentina.They began in the nineties with a forest in a newspaper column mass circulation. They went in search of new horizons and feedback nearest about forestry and , forest industrystakeholders, by means ofdevelopment seminars, courses, lectures, working committees, publications, implementing blogs, virtual classroom and using social network facebook .The actionsinitiated in 1998, with the first steps aimed at the implementation of actions to improvethe information flow and initiatives to consolidate a process of awareness of the importance of forest systemssustainability and competitiveness offorest industry.For the analysis, a methodology was adopted that allowed capture both the impact of issues prioritized and addressed strategies to achieve greater fluency in communication processes with a view to raise awareness and consolidate guidelines for achieving improved competitiveness of forestry SMEs and forest industryand sustainable forest management.The conclusions are: i) the importance of greater dynamism, commitment and participation to build consensus, concepts, principles that promote greater sustainability and competitiveness of these sectors ii) the need to raise awareness to promote a change aimed at improving the chain forest production, competitiveness and sustainability.Fil: Dorado, Mónica Liliana. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Lubrano, Pedro. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Siwinsky, Susana. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Rodríguez, M. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Mandrile, R. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina

Quantification of titanium dioxide (TiO2) anatase and rutile polymorphs in binary mixtures by Raman spectroscopy: an interlaboratory comparison

This article presents an interlaboratory comparison (ILC) on Raman spectroscopy as a technique for relative quantification of the two most common polymorphs of titanium dioxide (TiO2)-anatase and rutile-in binary mixtures. Some standard methods are currently employed internationally for the determination of TiO2 content in samples (ISO 591-1, ASTM D3720-90), but require extensive sample preparation, do not distinguish between the two polymorphs or are accurate only for small fractions of either polymorph. Raman spectroscopy is a well-suited characterization technique for measuring and differentiating TiO2 in a fast, non-invasive way, while requiring no particular reagent or sample preparation. Eleven international participants conducted the study under the framework of Versailles Project on Advanced Materials and Standards. The collected data was analyzed by means of partial least squares regression after spectral preprocessing. The resulting models all show discrepancies of lower than 2% from the nominal values in the quantitative analysis over the concentration range of 5%-95% mixture fractions, with many datasets showing substantial improvement margins on this figure. The results of this ILC provide validation of Raman spectroscopy as a reliable method for quantification of TiO2 phases

Desarrollo de una vacuna inactivada contra la epidermitis exudativa porcina utilizando dos adyuvantes

Staphylococcus hyicus es el agente responsable de provocar la Epidermitis exudativa, una afección de la piel que afecta a los lechones lactantes y destetados menores de 6 semanas de edad. Esta patología se caracteriza por generar lesiones con exudación grasa, descamación y la formación de vesículas. A nivel global presenta una alta incidencia, con una variabilidad en la morbilidad del 20% al 100%, mientras que la mortalidad oscila entre el 50% y el 75%. En Argentina no se dispone actualmente de una vacuna que prevenga esta enfermedad, a pesar de que la inmunización se ha mostrado como una estrategia efectiva en la prevención de los procesos infecciosos en animales. Por lo tanto, el objetivo central de este estudio fue desarrollar dos bacterinas autógenas dirigidas contra Staphylococcus hyicus. Una de estas bacterinas se formuló utilizando un adyuvante convencional (hidróxido de aluminio), mientras que la otra utilizó el adyuvante inmunoestimulante (ISPA). La vacuna se empleó para inmunizar a cerdas preñadas, que fueron agrupadas según el adyuvante utilizado en la inmunización. La evaluación clínica se centró en determinar la tolerancia de las cerdas a las bacterinas. El resultado de esta evaluación fue exitoso, lo que marca un paso importante en la investigación y el desarrollo de medidas preventivas ante la Epidermitis exudativa