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  • Contributions on corona onset voltage calculation for EHV and UHV substation connectors

     Hernandez Guiteras, Joan
    Defense's date: 2014-03-28
    Universitat Politècnica de Catalunya
    Theses

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    Les investigacions realitzades en aquesta tesi es va realitzar en el marc d'un acord empresa - universitat . L'objectiu d'aquesta investigació és determinar la tensió d'inici de l'efecte corona en geometries no uniformes per evitar la seva aparició, i així poder incidir en la fase de disseny del connectors de subestació de EHV i UHV i equipmanet auxiliar de línia instal·lats en condicions de funcionament, d'acord amb les normes internacionals . Per tant , s'ha prestat una consideració especial a l'estudi i el modelatge de l'efecte corona per assegurar que els connectors dissenyats es trobin gairebé lliures d'aquest efecte indesitjable . Degut a de la natura d'aquest acord marc, la investigació científica s'ha vist delimitada a l'aplicabilitat en un entorn industrial a fi d'obtenir la accreditació, segons les normatives internacionals, dels productes analitzats.Per tant , els temes tractats en aquesta investigació inclouen l'anàlisi de camps electromagnètics i els càlculs de l'efecte corona , sent aquest últim de gran importància en el disseny dels connectors de subestació per EHV i UHV . És objectiu d'aquesta tesi proporcionar augmentar el coneixement i aportar mètodes matemàtics apropiats per avaluar el comportament dielèctric de connectors de subestació per a sistemes de transmissió de EHV i UHV . En concret , s'ha destinat un capítol a la introducció a l'estat de la tècnica en connectors de la subestació i l'efecte corona, seguit d'un capítol adreçat a l'estudi dels camps elèctrics i magnètics creats pels connectors de la subestació i les equacions empíriques per al càlcul de l'effecte corona. A continuació, s'introdueix una descripció macroscòpica del corona a través de la descripció matemàtica del procés de ionització, tant des del cas estacionari com el transitori. Seguit de la descripció microscòpica a través de funcions de distribució estadístiques utilitzdes per descriure i calcular els paràmetres d'ionització del corona en l'aire . Finalment, es troba el capítol de tancament amb les principals aportacions de la investigació realitzada.

  • Redesign process of a 765 kV AC substation connector by means of 3D-FEM simulations

     Hernandez Guiteras, Joan; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Simulation modelling practice and theory
    Date of publication: 2014-03-03
    Journal article

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    This paper shows the capabilities of applying the three-dimensional finite element method (3D-FEM) for designing complex-shaped substation connectors to operate at 765 kVRMS AC. To check this methodology, it was analyzed the feasibility of upgrading a 400 kVRMS substation connector to operate at 765 kVRMS. However, both experimental and simulation results conducted according to the ANSI/NEMA CC 1-2009 standard concluded that although it passed the visual corona test, to ensure a wide safety margin it was desirable an improvement of the electrical behavior of such connector. It was shown that FEM results allowed detecting the peak stress points of the connector regarding the electrical stress thus allowing applying a corrective action. Then, two possible solutions were analyzed, i.e. the use of corona shields and the redesign of the connector assisted by 3D-FEM simulations. Results presented in this work show that both approaches have an excellent behavior in reducing the electric field strength on the connector surface. However, to make the final decision, the production cost of both alternatives was analyzed, thus favoring the redesign option. Next, the redesigned version of the substation connector was manufactured and tested. Experimental results conducted in a high voltage laboratory verified the effectiveness of the methodology and the potential of the proposed system to act as an advanced design tool for optimizing the behavior of complex-shaped substation connectors. Thus, this system allows assisting efficiently the design process while permitting constraining the economic costs

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    A Combined Methodology of Adaptive Neuro-Fuzzy Inference System and Genetic Algorithm for Short-term Energy Forecasting  Open access

     Kampouropoulos, Konstantinos; Andrade Rengifo, Fabio; Garcia Espinosa, Antonio; Romeral Martinez, Jose Luis
    Advances in Electrical and Computer Engineering
    Date of publication: 2014-02-01
    Journal article

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    This document presents an energy forecast methodology using Adaptive Neuro-Fuzzy Inference System (ANFIS) and Genetic Algorithms (GA). The GA has been used for the selection of the training inputs of the ANFIS in order to minimize the training result error. The presented algorithm has been installed and it is being operating in an automotive manufacturing plant. It periodically communicates with the plant to obtain new information and update the database in order to improve its training results. Finally the obtained results of the algorithm are used in order to provide a short-term load forecasting for the different modeled consumption processes.

    This document presents an energy forecast methodology using Adaptive Neuro-Fuzzy Inference System (ANFIS) and Genetic Algorithms (GA). The GA has been used for the selection of the training inputs of the ANFIS in order to minimize the training result error. The presented algorithm has been installed and it is being operating in an automotive manufacturing plant. It periodically communicates with the plant to obtain new information and update the database in order to improve its training results. Finally the obtained results of the algorithm are used in order to provide a shortterm load forecasting for the different modeled consumption processes.

  • Detection of interturn faults in PMSMs with different winding configuration

     Saavedra Ordoñez, Harold; Urresty Betancourt, Julio; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Energy conversion and management
    Date of publication: 2014-03-03
    Journal article

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    Interturn faults in permanent magnet synchronous motors (PMSMs) may develop fast into more severe faults such as coil-to-coil, phase-to-phase and phase-to-ground short circuits. These faults are very destructive and may irreversibly damage the PMSM. Therefore, it is highly desirable to develop suitable methods for the early detection of such faults. The effects of interturn faults are visible in both the stator currents and the zero-sequence voltage component (ZSVC) spectra. By designing appropriate fault diagnosis schemes based on the analysis of the harmonic content of such electric variables it is possible to detect short circuit faults in its early stage. However, the stator winding configuration of the PMSM deeply impacts the harmonic content of both spectra. This paper studies the effects of different stator winding configurations in both the stator currents and the ZSVC spectra of healthy and faulty machines. Results presented may help to develop fault diagnosis schemes based on the acquisition and further analysis of the stator currents and/or the ZSVC harmonic components.

  • Runout tracking in electric motors using self-mixing interferometry

     Atashkhooei, Reza; Urresty Betancourt, Julio; Royo Royo, Santiago; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE-ASME transactions on mechatronics
    Date of publication: 2014-01-17
    Journal article

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  • IPT-2011-1543-920000-Anualitat 2014

     Romeral Martinez, Jose Luis
    Participation in a competitive project

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  • Non-linear Control Algorithms for Enhanced Stability in Inverter-Based Microgrid

     Romeral Martinez, Jose Luis
    Participation in a competitive project

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  • LOAD FORECASTING ON THE USER SIDE BY MEANS OF COMPUTATIONAL INTELLIGENCE ALGORITHMS  Open access

     Cardenas Araujo, Juan Jose
    Defense's date: 2013-07-11
    Department of Electronic Engineering, Universitat Politècnica de Catalunya
    Theses

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    En el contexto energético actual y particularmente en el lado del usuario, el concepto de sistema de gestión energética (EMS) se presenta como una alternativa apropiada para mejorar continuamente la eficiencia energética. Los EMSs en combinación con las tecnologías informáticas dan origen al concepto de iEMS, que además de soportar las funciones de los EMS, tienen la capacidad de modelar, pronosticar, controlar y supervisar los consumos energéticos. Su principal objetivo es el de realizar una mejora continua, lo más autónoma posible y predictiva de la eficiencia energética.Este tipo de sistemas tienen como núcleo fundamental el sistema de modelado y pronóstico de consumos (Load Modelling and Forecast System, LMFS). El LMFS está habilitado para pronosticar el comportamiento futuro de cargas y, si es necesario, de generadores. Es sobre estos pronósticos sobre los cuales el iEMS puede realizar sus tareas automáticas y predictivas de optimización y supervisión. Los LMFS en el lado del usuario son el foco de esta tesis.Un LMFS en el lado del usuario, diseñado para soportar un iEMS requiere o demanda ciertas características que en otros contextos no serían tan necesarias. En primera estancia, los perfiles de los usuarios tienen un alto grado de aleatoriedad que los hace más difíciles de pronosticar. Segundo, el gran número de puntos a modelar requiere que el LMFS tenga por un lado, un nivel elevado de autonomía para generar de la manera más desatendida posible los modelos. Por otro lado, necesita un nivel elevado de adaptabilidad para que, usando la misma estructura o metodología, pueda modelar diferentes tipos de cargas cuya procedencia pude variar significativamente.Por lo tanto, los sistemas de modelado abordados en esta tesis son aquellos que no solo buscan mejorar la precisión, sino también la adaptabilidad y autonomía. En busca de estos objetivos y soportados principalmente por algoritmos de inteligencia computacional, procesamiento de señales y estadística, hemos propuesto tres algoritmos novedosos para el desarrollo de un LMFS en el lado del usuario.El primero de ellos busca mejorar la adaptabilidad del LMFS manteniendo una buena precisión y capacidad de autonomía. Denominado ETA, consiste del uso de una estructura ANFIS que es entrenada por un algoritmo genético multi objetivo(MOGA). Como resultado de este híbrido, obtenemos un algoritmo con excelentes capacidades de generalización y fácil de adaptar para el entrenamiento y evaluación de nuevas estructuras adaptativas basadas en ANFIS.El segundo de los algoritmos desarrollados aborda la autonomía del LMFS para así poder generar modelos de múltiples cargas. Al igual que en la anterior propuesta usamos un ANFIS y un MOGA, pero esta vez el MOGA en vez de entrenar el ANFIS, se utiliza para encontrar la configuración cuasi-óptima del ANFIS. Encontrar la onfiguración apropiada de un ANFIS es muy importante para obtener un buen funcionamiento del LMFS en lo que a precisión y generalización respecta. El LMFSpropuesto, además de configurar automáticamente el ANFIS, incluyó diversos algoritmos para procesar los datos puros que casi siempre estuvieron contaminados de datos espurios y gaps de información, operando satisfactoriamente en lascondiciones de prueba en un escenario real.El tercero y último de los algoritmos buscó mejorar la precisión manteniendo la autonomía y adaptabilidad, aprovechando para ello la existencia de patrones dominantes de más baja resolución temporal que el consumo objetivo, y que son másfáciles de modelar y pronosticar. La metodología desarrollada se basa en la transformada de Hilbert-Huang para detectar y seleccionar tales patrones dominantes. Además, esta metodología define el uso de modelos parciales de los patronesdominantes seleccionados, para mejorar la precisión del LMFS y mitigar el problema de aleatoriedad que afecta a los consumos en el lado del usuario

    Nowadays, it would be very difficult to deny the need to prioritize sustainable development through energy efficiency at all consumption levels. In this context, an energy management system (EMS) is a suitable option for continuously improving energy efficiency, particularly on the user side. An EMS is a set of technological tools that manages energy consumption information and allows its analysis. EMS, in combination with information technologies, has given rise to intelligent EMS (iEMS), which, aside from lending support to monitoring and reporting functions as an EMS does, it has the ability to model, forecast, control and diagnose energy consumption in a predictive way. The main objective of an iEMS is to continuously improve energy efficiency (on-line) as automatically as possible. The core of an iEMS is its load modeling forecasting system (LMFS). It takes advantage of historical information on energy consumption and energy-related variables in order to model and forecast load profiles and, if available, generator profiles. These models and forecasts are the main information used for iEMS applications for control and diagnosis. That is why in this thesis we have focused on the study, analysis and development of LMFS on the user side. The fact that the LMFS is applied on the user side to support an iEMS means that specific characteristics are required that in other areas of load forecasting they are not. First of all, the user-side load profiles (LPs) have a higher random behavior than others, as for example, in power system distribution or generation. This makes the modeling and forecasting process more difficult. Second, on the user side --for example an industrial user-- there is a high number and variety of places that can be monitored, modeled and forecasted, as well as their precedence or nature. Thus, on the one hand, an LMFS requires a high degree of autonomy to automatically or autonomously generate the demanded models. And on the other hand, it needs a high level of adaptability in order to be able to model and forecast different types of loads and different types of energies. Therefore, the addressed LMFS are those that do not look only for accuracy, but also adaptability and autonomy. Seeking to achieve these objectives, in this thesis work we have proposed three novel LMFS schemes based on hybrid algorithms from computational intelligence, signal processing and statistical theory. The first of them looked to improve adaptability, keeping in mind the importance of accuracy and autonomy. It was called an evolutionary training algorithm (ETA) and is based on adaptivenetwork-based-fuzzy-inference system (ANFIS) that is trained by a multi-objective genetic algorithm instead of its traditional training algorithm. As a result of this hybrid, the generalization capacity was improved (avoiding overfitting) and an easily adaptable training algorithm for new adaptive networks based on traditional ANFIS was obtained. The second scheme deals with LMF autonomy in order to build models from multiple loads automatically. Similar to the previous proposal, an ANFIS and a MOGA were used. In this case, the MOGA was used to find a near-optimal configuration for the ANFIS instead of training it. The LMFS relies on this configuration to work properly, as well as to maintain accuracy and generalization capabilities. Real data from an industrial scenario were used to test the proposed scheme and the multi-site modeling and self-configuration results were satisfactory. Furthermore, other algorithms were satisfactorily designed and tested for processing raw data in outlier detection and gap padding. The last of the proposed approaches sought to improve accuracy while keeping autonomy and adaptability. It took advantage of dominant patterns (DPs) that have lower time resolution than the target LP, so they are easier to model and forecast. The Hilbert-Huang transform and Hilbert-spectral analysis were used for detecting and selecting the DPs. Those selected were used in a proposed scheme of partial models (PM) based on parallel ANFIS or artificial neural networks (ANN) to extract the information and give it to the main PM. Therefore, LMFS accuracy improved and the user-side LP noising problem was reduced. Additionally, in order to compensate for the added complexity, versions of self-configured sub-LMFS for each PM were used. This point was fundamental since, the better the configuration, the better the accuracy of the model; and subsequently the information provided to the main partial model was that much better. Finally, and to close this thesis, an outlook of trends regarding iEMS and an outline of several hybrid algorithms that are pending study and testing are presented.

    En el contexto energético actual y particularmente en el lado del usuario, el concepto de sistema de gestión energética (EMS) se presenta como una alternativa apropiada para mejorar continuamente la eficiencia energética. Los EMSs en combinación con las tecnologías informáticas dan origen al concepto de iEMS, que además de soportar las funciones de los EMS, tienen la capacidad de modelar, pronosticar, controlar y supervisar los consumos energéticos. Su principal objetivo es el de realizar una mejora continua, lo más autónoma posible y predictiva de la eficiencia energética. Este tipo de sistemas tienen como núcleo fundamental el sistema de modelado y pronóstico de consumos (Load Modeling and Forecasting System, LMFS). El LMFS está habilitado para pronosticar el comportamiento futuro de cargas y, si es necesario, de generadores. Es sobre estos pronósticos sobre los cuales el iEMS puede realizar sus tareas automáticas y predictivas de optimización y supervisión. Los LMFS en el lado del usuario son el foco de esta tesis. Un LMFS en el lado del usuario, diseñado para soportar un iEMS requiere o demanda ciertas características que en otros contextos no serían tan necesarias. En primera estancia, los perfiles de los usuarios tienen un alto grado de aleatoriedad que los hace más difíciles de pronosticar. Segundo, en el lado del usuario, por ejemplo en la industria, el gran número de puntos a modelar requiere que el LMFS tenga por un lado, un nivel elevado de autonomía para generar de la manera más desatendida posible los modelos. Por otro lado, necesita un nivel elevado de adaptabilidad para que, usando la misma estructura o metodología, pueda modelar diferentes tipos de cargas cuya procedencia pude variar significativamente. Por lo tanto, los sistemas de modelado abordados en esta tesis son aquellos que no solo buscan mejorar la precisión, sino también la adaptabilidad y autonomía. En busca de estos objetivos y soportados principalmente por algoritmos de inteligencia computacional, procesamiento de señales y estadística, hemos propuesto tres algoritmos novedosos para el desarrollo de un LMFS en el lado del usuario. El primero de ellos busca mejorar la adaptabilidad del LMFS manteniendo una buena precisión y capacidad de autonomía. Denominado ETA, consiste del uso de una estructura ANFIS que es entrenada por un algoritmo genético multi objetivo (MOGA). Como resultado de este híbrido, obtenemos un algoritmo con excelentes capacidades de generalización y fácil de adaptar para el entrenamiento y evaluación de nuevas estructuras adaptativas basadas en ANFIS. El segundo de los algoritmos desarrollados aborda la autonomía del LMFS para así poder generar modelos de múltiples cargas. Al igual que en la anterior propuesta usamos un ANFIS y un MOGA, pero esta vez el MOGA en vez de entrenar el ANFIS, se utiliza para encontrar la configuración cuasi-óptima del ANFIS. Encontrar la configuración apropiada de un ANFIS es muy importante para obtener un buen funcionamiento del LMFS en lo que a precisión y generalización respecta. El LMFS propuesto, además de configurar automáticamente el ANFIS, incluyó diversos algoritmos para procesar los datos puros que casi siempre estuvieron contaminados de datos espurios y gaps de información, operando satisfactoriamente en las condiciones de prueba en un escenario real. El tercero y último de los algoritmos buscó mejorar la precisión manteniendo la autonomía y adaptabilidad, aprovechando para ello la existencia de patrones dominantes de más baja resolución temporal que el consumo objetivo, y que son más fáciles de modelar y pronosticar. La metodología desarrollada se basa en la transformada de Hilbert-Huang para detectar y seleccionar tales patrones dominantes. Además, esta metodología define el uso de modelos parciales de los patrones dominantes seleccionados, para mejorar la precisión del LMFS y mitigar el problema de aleatoriedad que afecta a los consumos en el lado del usuario. Adicionalmente, se incorporó el algoritmo de auto configuración que se presentó en la propuesta anterior para hallar la configuración cuasi-óptima de los modelos parciales. Este punto fue crucial puesto que a mejor configuración de los modelos parciales mayor es la mejora en precisión del pronóstico final. Finalmente y para cerrar este trabajo de tesis, se realizó una prospección de las tendencias en cuanto al uso de iEMS y se esbozaron varias propuestas de algoritmos híbridos, cuyo estudio y comprobación se plantea en futuros estudios.

  • Study of stability and non-linear control applied to microgrid

     Andrade Rengifo, Fabio
    Defense's date: 2013-11-07
    Department of Electronic Engineering, Universitat Politècnica de Catalunya
    Theses

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    Generadores renovables de carácter intermitente se han incrementado significativamente en los últimos años. Aquellos generadores con interface de salida de electrónica de potencia, como sistemas fotovoltaicos o eólicos, están conectados y gestionados por un sistema de control inteligente. Cuando el sistema de control inteligente también gestiona consumidores locales y dispositivos de almacenamiento de energía se constituye una Microgrid.Estos generadores conectados en Microgrid son altamente eficientes, fiables, modulares, ecológicos, silenciosos, etc. Debido a todo esto, serán un competidor importante en los mercados de energía en el futuro.En el estado del arte, el estudio de la estabilidad de Microgrids existen varias estructuras de conexión. Se muestran un claro predominio de inversores en paralelo con lazos de control de tensión y corriente, utilizando las curvas de droop entre ¿Potencia Activa Vs Frecuencia¿ y ¿Potencia Reactiva Vs a Tensión¿ para manejar la potencia entregada a las cargas. Generalmente los modelos de una Microgrid han sido linealizado alrededor de un punto de funcionamiento y operan bajo pequeñas disturbios. Diferentes autores han estudiado e identificado las raíces del sistema en el plano complejo, la forma en que las raíces se están moviendo en el plano en función de pequeñas variaciones de los parámetros del sistema, parámetros tales como las pendientes de las curvas droop, impedancias de línea, etc.Sin embargo, estos modelos sólo son válidos, mientras que el sistema no sufre grandes variaciones en torno a este punto de funcionamiento.Por lo tanto, estos modelos no reflejan una realidad en Microgrids cuando sufren cambios importantes, por ejemplo la conexión o desconexión de la red pública de forma inesperada, o fuentes de generación intermitente. Comúnmente, en generadores de energías renovables, se puede pasar de entregar potencia máxima a no entregar potencia en tiempos muy cortos, debido a un cambio inesperado en el medio ambiente.Esta tesis aplica la teoría actual de los sistemas de análisis no lineal, tales como los métodos de Lyapunov, procedimientos Popov y planos de fase, para determinar la estabilidad de la Microgrid contra cambios repentinos en las energías de entrada y propone una metodología de control para mejorar su estabilidad.Para apoyar los nuevos modelos propuestos, se desarrolló el concepto de máquina electrostática. Esto permite que los generadores basados en convertidores de electrónicos de potencia puedan modelarse como máquinas rotativas electrostáticas, con variaciones en la tensión de entrada. Además, este modelo matemático permite el análisis de las fuentes de energía renovables para cualquier punto de funcionamiento, incluso con el suministro de energía discontinua (bus de CC no constante).También, esta tesis presenta herramientas de análisis por medio de las funciones de Lyapunov que podrían ser utilizados para el análisis de estabilidad de gran señal en Microgrids. Además, esta metodología permite la búsqueda de los límites de la región de estabilidad.El modelo y la metodología propuestos permite analizar diferentes tipos de Microgrid con n-generadores conectados de diferentes maneras en presencia de grandes variaciones de la energía de entrada.Finalmente, se han presentado simulaciones y resultados experimentales con el fin de validar la metodología propuesta , el análisis de la estabilidad y métodos de control.

  • An Energy Management Strategy for Plug-in Hybrid Electric Vehicles  Open access

     Bader, Benjamin
    Defense's date: 2013-11-29
    Department of Electronic Engineering, Universitat Politècnica de Catalunya
    Theses

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    Esta tesis formula una propuesta de una estrategia para la gestión de energía (EMS) en vehículs híbridos eléctricos enchufables para el uso en tiempo real. La EMS está desarollada para minimizar el consumo de combustible del vehículo a través de la utilización de la energía eléctrica almacenada y de la operación de los componentes del sistema de propulsión en alta eficiencia. Este objetivo se consigue mediante el desarrollo de un EMS predictivo, lo que, además de minimizar el consumo de combustible, está optimizado en términos de coste computacional y maniobrabilidad.La necesidad de una EMS en coches híbridos proviene de la integración de dos almacenes de energía y convertidores en la cadena de tracción. En el caso de un coche híbrido (HEV) normalmente es un motor de combustión y una o dos máquinas eléctricas alimentadas por una batería. Durante la operación del vehículo, la EMS controla la distribución de energía entre motor de combustión y máquina eléctrica. La distribución de energía está optimizado según la eficiencia de los componentes en función de su punto operación tanto como el nivel de energía de la batería y los datos de predicción del futuro ciclo de conducción.Además del aumento de la economía de combustible, la hibridación del tren de potencia permite la sustitución de gasolina por energía eléctrica, mediante la opción de recarga externa de la batería a través de la red eléctrica. Esta clase de vehículo, que incorpora una batería recargable a través de la red eléctrica, es conocido como coche híbrido enchufable (PHEV). PHEVs comparten características tanto de los vehículos híbridos como de los vehículos eléctricos y combinas varias ventajas de ambas tecnologías.La característica de la batería recargable del PHEV hace que el desarrollo de la EMS sea especialmente desafiante. Para minimizar el consumo de gasolina, la batería se descarga de manera óptima sobre toda la duración del trayecto, priorizando el uso de energía eléctrica en situaciones que permiten un máximo de ahorro de gasolina. Por lo tanto, una EMS de PHEV depende en gran medida del conocimiento previo sobre el trayecto, es decir de la futura velocidad del vehículo y la inclinación de la carretera. Esto requiere que el conductor indique la ruta a el EMS. La indicación de la ruta, en combinación con un sístema de navegación que utiliza información sobre la altura del terreno, el tipo de carretera (por ejemplo, autopista o carretera nacional) y el límite de velocidad puede ser evaluado por un algoritmo de predicción de velocidad. En combinación con los avances de tecnologías como los sistemas de transporte inteligentes (ITS) harán una información más exacta de tráfico para mejorar la predicción en futuro. A pesar de esto, los errores en los datos de predicción tienen que ser considerados y por lo tanto también se consideran en este trabajo.El EMS desarrollado en esta tesis combina enfoques diferentes que se ejecutan paso a paso. Una primera aproxiamción del nivel de energía de la batería se obtiene por un algoritmo basado en un mixed integer linear program (MILP). Eso es especialmente importante para trayectos con fases largas de cuestas arriba, cuestas abajo o urbanos, es decir, las secciones con un requisito particularmente alto o bajo de energía. Los resultados de esta optimización son luego refinados por un algoritmo de programación dinámico (DP), que calcula la distribución del par y la marcha durante el trayecto con un horizonte de predicción retroceso. Como DP es computacional muy intensivo, se presentan técnicas para reducir los costes de cómputo. Por último, desde la optimización una estrategia de regla basada es extraída y optimizada en línea utilizando una máquina de soporte de vectores (SVM). Este paso es necesario para asegurar maniobrabilidad y un mínimo consumo de combustible del vehículo también para los datos de predicción inexacta.

    This dissertation formulates a proposal for a real time implementable energy management strategy (EMS) for plug-in hybrid electric vehicles. The EMS is developed to minimize vehicle fuel consumption through the utilisation of stored electric energy and high-efficiency operation of powertrain components. This objective is achieved through the development of a predictive EMS, which, in addition to fuel efficiency, is optimized in terms of computational cost and drivability. The requirement for an EMS in hybrid powertrain vehicles stems from the integration of two energy stores and converters in the powertrain; in the case of hybrid electric vehicles (HEVs) usually a combustion engine and one or more electric machines powered by a battery. During operation of the vehicle the EMS controls power distribution between engine and electric traction motor. Power distribution is optimized according to the operating point dependent efficiencies of the components, energy level of the battery and trip foreknowledge. Drivability considerations, e.g. frequency of engine starts, can also be considered. Due to high oil prices and legislative requirements caused by the environmental impact of greenhouse emissions, fuel economy has gained importance in recent years. In addition to increased fuel economy, powertrain hybridization permits the substituton of fuel for electrical energy by implementing an external recharging option for the battery. This vehicle class, incorporating a battery rechargeable via the electrical grid, is known as a plug-in HEV (PHEV). PHEV share characteristics of both HEVs and all-electric vehicles combining several advantages of both technologies. The rechargeable battery feature of the PHEVs makes their EMS development espe-cially challenging. For minimal fuel consumption, the battery is discharged optimally over the whole trip length, prioritising electrical energy when driving conditions are such that its use maximises the fuel saving that can be achieved. Therefore, an EMS for a PHEV depends heavily on the availability of a priori knowledge about the trip, i.e. the knowledge about future vehicle speed and road grade. This requires the driver to indi-cate the route before trip start. The route knowledge in combination with GPS or Galileo based next generation navigation systems using information from a geographic in-formation system (GIS) about terrain height profile, road type (e.g. motorway or country road), and legal speed limits can be evaluated by a speed prediction algorithm including information about the driver's behaviour for a detailed prediction of the trip. These navigation systems and algorithms in combination with expected future advances and the deployment of technologies such as intelligent transport systems (ITS) and vehicle-to-vehicle communication (V2V), will make more exact traffic information available to further improve prediction. Despite expected advances in prediction quality, inaccuracy of prediction data has to be considered and is therefore regarded in this work. The EMS proposed in this dissertation combines different approaches which are exe-cuted step by step. A first approximation of the energy distribution during the trip is based on a mixed integer linear program (MILP), which gives the optimal energy state of the battery during the trip. This is especially important for trips with long uphill, downhill or urban phases, i.e. sections with a particularly high or lower power requirement. The results from MILP are then used by a dynamic programming (DP) algorithm to calculate optimal torque and gear using a receding prediction horizon. Using a receding prediction horizon, an important reduction of computational cost is achieved. Lastly, from the DP results a rule-based strategy is extracted using a support vector machine (SVM). This last step is necessary to ensure the drivability of the vehicle also for inaccurate prediction data.

  • Stability analysis of a microgrid system based on inverter-interfaced distributed generators

     Andrade Rengifo, Fabio; Kampouropoulos, Konstantinos; Cusido Roura, Jordi; Romeral Martinez, Jose Luis
    Advances in Electrical and Computer Engineering
    Date of publication: 2013
    Journal article

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    This paper presents a phase-plane trajectory analysis and the appliance of Lyapunov´s methodology to evaluate the stability limits of a small signal model of a Microgrid system. The work done is based on a non-linear tool and several computer simulations. The study indicates how to analyze a Microgrid system that is subjected to a severe transient disturbance by using its large signal model without the necessity of the small signal analysis as it is commonly applied.

    This paper presents a phase-plane trajectory analysis and the appliance of Lyapunov´s methodology to evaluate the stability limits of a small signal model of a Microgrid system. The work done is based on a non-linear tool and several computer simulations. The study indicates how to analyze a Microgrid system that is subjected to a severe transient disturbance by using its large signal model without the necessity of the small signal analysis as it is commonly applied.

  • Influence of the stator windings configuration in the currents and zero-sequence voltage harmonics in permanent magnet synchronous motors with demagnetization faults

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE transactions on magnetics
    Date of publication: 2013-08
    Journal article

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    Demagnetization faults in permanent magnet synchronous motors may generate specific fault harmonic frequencies in the stator currents and the zero-sequence voltage component (ZSVC) spectra. Hence, by analyzing the stator currents or/and the ZSVC spectra it is possible to develop fault diagnosis schemes to detect such faults. In order to have a broad view of such effects, a representative set of stator windings configurations must be considered. By analyzing different stator windings configurations this paper shows that the amplitude of the harmonic frequencies of both the stator currents and the ZSVC spectrato be analyzed are significantly influenced by the stator windings configuration. It is also proved that depending on the winding configuration, new harmonic components may emerge in both spectra. The results presented in this paper may help to develop fault diagnosis schemes based on the acquisition and further analysis of the stator currents and the ZSVC harmonic components.

  • Shaft Trajectory Analysis in a Partially Demagnetized Permanent-Magnet Synchronous Motor

     Urresty Betancourt, Julio César; Atashkhooei, Reza; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis; Royo Royo, Santiago
    IEEE transactions on industrial electronics
    Date of publication: 2013-08-01
    Journal article

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    Demagnetization faults have a negative impact on the behavior of permanent-magnet synchronous machines, thus reducing their efficiency, generating torque ripple, mechanical vibrations, and acoustic noise, among others. In this paper, the displacement of the shaft trajectory induced by demagnetization faults is studied. It is proved that such faults may increase considerably the amplitude of the rotor displacement. The direct measure of the shaft trajectory is performed by means of a noncontact self-mixing interferometric sensor. In addition, the new harmonics in the back electromotive force (EMF) and the stator current spectrum arising from the shaft displacement are analyzed by means of finite-element method (FEM) simulations and experimental tests. Since conventional finite-element electromagnetic models are unable to predict the harmonics arising from the shaft trajectory displacement, an improved finite-element model which takes into account the measured trajectory has been developed...

    Abstract—Demagnetization faults have a negative impact on the behavior of permanent-magnet synchronous machines, thus reducing their efficiency, generating torque ripple, mechanical vibrations, and acoustic noise, among others. In this paper, the displacement of the shaft trajectory induced by demagnetization faults is studied. It is proved that such faults may increase considerably the amplitude of the rotor displacement. The direct measure of the shaft trajectory is performed by means of a noncontact self-mixing interferometric sensor. In addition, the new harmonics in the back electromotive force (EMF) and the stator current spectrum arising from the shaft displacement are analyzed by means of finite-element method (FEM) simulations and experimental tests. Since conventional finite-element electromagnetic models are unable to predict the harmonics arising from the shaft trajectory displacement, an improved finite-element model which takes into account the measured trajectory has been developed. It is shown that this improved model allows obtaining more accurate back EMF and stator current spectra than those obtained by means of conventional models. This work presents a comprehensive analysis of the effects generated by demagnetization faults, which may be useful to develop improved fault diagnosis schemes

  • Diagnosis of interturn faults in pmsms operating under nonstationary conditions by applying order tracking filtering

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE transactions on power electronics
    Date of publication: 2013
    Journal article

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    Interturn faults in permanent magnet synchronous machines may have very harmful effects if not early identified. This study deals with the detection of such faults when the machine operates under varying speed conditions. The performance of two methods is analyzed and compared, i.e., the analysis of the third harmonic of the stator currents and the first one of the zero- sequence voltage components. The Vold¿Kalman filtering order tracking algorithm is introduced and applied to track the harmonics of interest when the machine operates under a wide speed range and different load levels. This study also presents two reliable fault indicators especially focused to detect stator winding interturn faults under nonstationary speed conditions. Experimental results endorse the methodology proposed, showing its potential to carry out a reliable fault diagnosis scheme

  • A back-emf based method to detect magnet failures in PMSMs

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE transactions on magnetics
    Date of publication: 2013
    Journal article

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    Demagnetization faults are troublesome because they have a profound impact on the overall performance of permanent magnet synchronous motors (PMSMs). This work presents and veri¿es experimentally a system to detect such faults which is based on the measure of the zero sequence voltage component (ZSVC). The proposed method is also appropriate for inverter fed machines and is particularly useful when dealing with fault tolerant systems. A fault severity index which allows quantifying the harshness of such faults is also proposed and its behavior is analyzed from experimental data. Features of the proposed method include low computational burden, simplicity and high sensitivity. Experimental results conducted at different speed and load conditions show the potential of the proposed fault severity index for online diagnosis of demagnetization failures

  • Fault detection and fault tolerant operation of a five phase PM motor drive using adaptive model identification approach

     Salehifar, Mehdi; Salehi Arashloo Arashloo, Ramin; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicente Miguel; Romeral Martinez, Jose Luis
    IEEE Journal of emerging and selected topics in power electronics
    Date of publication: 2013-12-03
    Journal article

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  • IPT-2011-1543-920000

     Romeral Martinez, Jose Luis
    Participation in a competitive project

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  • Modelica library of detailed magnetic effects in rotating machinery

     Romeral Martinez, Jose Luis
    Participation in a competitive project

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  • Access to the full text
    Magnet shape influence on the performance of AFPMM with demagnetization  Open access

     Saavedra Ordoñez, Harold; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Annual Conference of the IEEE Industrial Electronics Society
    Presentation's date: 2013-11-13
    Presentation of work at congresses

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    In this paper the effect of the magnets shape on the AFPMM performance under a demagnetization fault has been analyzed by means of 3D-FEM simulations. Demagnetization faults in permanent magnet synchronous motors (PMSMs) may generate specific fault harmonic frequencies in the stator currents, output torque and the zero-sequence voltage component (ZSVC) spectra the ones can affect motor behavior, and so these parameters have been studied and compared, for each magnet configuration in each condition. These analyses are carried out to find out the more suitable geometry for an operation under healthy and faulty condition.

  • A novel broken rotor bar fault detection method using park's transform and wavelet decomposition

     Salehi Arashloo Arashloo, Ramin; Romeral Martinez, Jose Luis; Salehifar, Mehdi
    IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives
    Presentation's date: 2013-08
    Presentation of work at congresses

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    Detection of broken rotor bars has been an important but difficult work in fault diagnosis area of induction motors. The characteristic frequency components of faulted rotor are very close to the power frequency component but by far less in amplitude, which brings about great difficulty for accurate detection. In the present study, a new method is proposed in order to remove the main frequency component, resulting in more efficient detection of the rotor fault characteristics in the frequency spectrum of stator currents. The method is based on Park's transformation in combination with discrete wavelet decomposition to eliminate the effect of main frequency and zoom on the energy of objective fault related frequency components. In addition, the method efficiency is evaluated using Simulations in Matlab.

  • A simple and robust method for open switch fault detection in power converters

     Salehifar, Mehdi; Salehi Arashloo Arashloo, Ramin; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicente Miguel; Romeral Martinez, Jose Luis
    IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives
    Presentation's date: 2013-08-27
    Presentation of work at congresses

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    In this paper, a new fault detection method based on signal normalization using a simple trigonometric function is presented and applied to a five phase converter for fault tolerant application under nonsinusoidal unbalanced current waveforms. Generality, simplicity, ability to localize faulty switch, multiple switch fault detection and robustness are achieved using this approach. Once theory is explained,simulation results with Matlab/Simulink and experimental waveforms are described to show the effectiveness of the proposed detection method. Experimenal results corroborate these simulation results.

  • Improved open switch fault detection based on normalized current analysis in multiphase fault tolerant converters

     Salehifar, Mehdi; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicente Miguel; Salehi Arashloo Arashloo, Ramin; Romeral Martinez, Jose Luis
    IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives
    Presentation's date: 2013-08-28
    Presentation of work at congresses

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    A new open switch fault detection method based on normalized current analysis is proposed for application in multiphase fault tolerant PMSM drives. Performance characteristics of proposed method are single diagnostic variable, ability to detect open phase fault without using auxiliary variable, ability to detect multiple switch fault, simple diagnostic variable, generality, and robustness in case of high unbalanced current waveforms. Theory of diagnostic method with special multiphase drive application is developed; simulation results using Matlab/Simulink and experimental waveforms are shown to validate effectiveness of the presented fault detection method.

  • Intelligent sensor based on acoustic emission analysis applied to gear fault diagnosis

     Zurita Millan, Daniel; Delgado Prieto, Miguel; Ortega Redondo, Juan Antonio; Romeral Martinez, Jose Luis
    IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives
    Presentation's date: 2013-08-28
    Presentation of work at congresses

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    The development of intelligent and autonomous monitoring systems applied to rotating machinery, represents the evolution towards the automatic industrial plants supervision. In this regard, an acoustic emission based intelligent sensor is presented in this work. The proposed sensor records regularly the acoustic emission signal generated by gearboxes. A time domain statistical analysis is applied in order to characterize the acquired data. Afterwards, a neural network based algorithm is applied to detect gear fault patterns. Finally, the diagnosis result is sent through a wireless transceiver to the central control unit. Moreover, in order to reach a real autonomous operation, the sensor power is approached by different energy harvesting solutions.

  • Inter-turn fault detection in five-phase PMSMs. Effects of the fault severity

     Saavedra Ordoñez, Harold; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives
    Presentation's date: 2013-08-30
    Presentation of work at congresses

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    This paper deals with the effects of inter-turn short circuit faults in five-phase permanent magnet synchronous motors (PMSMs). For this purpose a finiteelements model (FEM) of a faulty machine with 1, 2 and 4 inter-turns in short circuit is analyzed. From the results of this model the effects of these fault severities in the stator currents and zero-sequence voltage components (ZSVC) harmonics is analyzed and the possibility of developing a fault diagnosis scheme based on the changes in their spectral content is exposed. Moreover, the effect of the fault severity on the total power losses in the machine is presented. Inter-turn faults generate large circulating currents which may lead to catastrophic failures. Therefore it is very important to know the increase in power losses in the machine due to the occurrence of such faults for applying corrective actions at the precise time once the fault has been diagnosed.

  • Reduction of the prediction horizon of predictive energy management for a plug-in HEV in hilly terrain

     Bader, Benjamin; Torres Carbonell, Oriol; Ortega Redondo, Juan Antonio; Lux, G.; Romeral Martinez, Jose Luis
    International Conference on Urban Transport and the Environment
    Presentation's date: 2013-05
    Presentation of work at congresses

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    Due to the great weight and high costs of electric energy storage systems (ESS), the number of pure electric vehicles (EV) is increasing only slowly. As a compromise between the autonomous hybrid electric vehicle (HEV) and EV, the plug-in HEV (PHEV) allows, like the EV, the recharging of the battery by the grid but brings also a combustion engine so as not to depend on the limited electric range of the vehicle. Next to the sizing of the vehicle components, the energy management strategy has an important influence on the fuel consumption of the vehicle. To minimize fuel consumption, predictive energy management is necessary, as all stored electric energy should be consumed by the end of the trip. In this way it is possible to minimize fuel consumption by substituting as much fuel as possible by the use of electric energy. In order to reach the global optimal result, a prediction horizon of the optimization for the duration of the entire trip is necessary. However, due to model uncertainties and the limited calculation capacities of the control units in a vehicle the global optimum cannot be achieved. Therefore, measures have to be taken to reduce the computation cost on the one hand and achieve results close the global optimum on the other. One of these measures, next to an adequate optimization algorithm, is the reduction of the prediction horizon. In this study, for a real life cycle including urban and highway parts a variation of the prediction horizon is carried out and the influence on the fuel consumption is simulated. The respective results are calculated using Dynamic Programming to exclude any influence of the chosenCenergy management strategy. The results are compared to the global optimal fuel consumption of the used driving cycle.

  • Model predictive current control of five phase permanent magnet motor

     Salehi Arashloo Arashloo, Ramin; Romeral Martinez, Jose Luis; Salehifar, Mehdi; Moreno Eguilaz, Juan Manuel
    European Conference on Power Electronics and Applications
    Presentation's date: 2013-09-03
    Presentation of work at congresses

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    This paper deals with model predictive control of five phase permanent magnet motors. Using motor model, the stator currents are estimated for the following modulation period, and the required voltages are applied to minimize the current errors. A comparison between the proposed algorithm and conventional cascade PI configuration is conducted.

  • Ripple free fault tolerant control of five phase permanent magnet machines

     Salehi Arashloo Arashloo, Ramin; Salehifar, Mehdi; Romeral Martinez, Jose Luis; Sala Caselles, Vicente Miguel
    European Conference on Power Electronics and Applications
    Presentation's date: 2013-09-03
    Presentation of work at congresses

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    This study is dealt with fault tolerant control of five phase permanent magnet (PM) machines. The main objectives are to increase the output power while eliminating the generated torque ripples. As a new aspect, the effect of available neutral connection is evaluated on the output power and torque ripples.

  • A novel broken rotor bar fault detection method using park¿s transform and wavelet decomposition

     Salehi Arashloo Arashloo, Ramin; Romeral Martinez, Jose Luis; Salehifar, Mehdi
    IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives
    Presentation's date: 2013-08-29
    Presentation of work at congresses

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    Detection of broken rotor bars has been an important but difficult work in fault diagnosis area of induction motors. The characteristic frequency components of faulted rotor are very close to the power frequency component but by far less in amplitude, which brings about great difficulty for accurate detection. In the present study, a new method is proposed in order to remove the main frequency component, resulting in more efficient detection of the rotor fault characteristics in the frequency spectrum of stator currents. The method is based on Park’s transformation in combination with discrete wavelet decomposition to eliminate the effect of main frequency and zoom on the energy of objective fault related frequency components. In addition, the method efficiency is evaluated using Simulations in Matlab.

  • Influence of the final drive ratio, electric motor size and battery capacity on fuel consumption of a parallel plug-in hybrid electric vehicle

     Torres Carbonell, Oriol; Bader, Benjamin; Romeral Martinez, Jose Luis; Lux, G.; Ortega Redondo, Juan Antonio
    International Conference on Urban Transport and the Environment
    Presentation's date: 2013-05
    Presentation of work at congresses

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    The purpose of this paper is to study the influence of the electric motor (EM) size, final drive ratio (FD) and the battery capacity (BAT) of a parallel plug-in hybrid electric vehicle (PHEV) regarding fuel consumption. The energy efficiency of a certain vehicle drivetrain depends on the size of the components. For this reason and for cost reasons it is necessary to study the optimal dimensions of the components that minimize the fuel consumption for a given driving cycle. In this publication the influence of the size of the electric motor, final drive ratio and also the battery capacity are analysed using the Response Surface Methodology (RSM) of the Design of Experiments (DoE) technique. A parallel PHEV has been parameterized and simulated to obtain the fuel consumption over NEDC driving cycle using Modelica/Dymola. This paper contains an introduction, a brief explanation of the modelled parallel HEV, a description of the all electric range operating strategy based on rules, an explanation of the RSM method, the simulation results, and finally the conclusions of this study.

  • Magnet shape influence on the performance of AFPMM in a torus configuration

     Saavedra Ordoñez, Harold; Riba Ruiz, Jordi Roger; Hernandez Guiteras, Joan; Romeral Martinez, Jose Luis
    International Conference on Power Engineering, Energy and Electrical Drives
    Presentation's date: 2013-05-16
    Presentation of work at congresses

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    The axial flux permanent magnet machine (AFPMM)is being increasingly demanded for special applications, particularly for transportation systems and concretely for inwheel applications. In this paper the effect of the magnets shape on the AFPMM performance has been analyzed by means of 3DFEM simulations. To this end the air-gap magnetic flux density, the back electromotive force (back-EMF), the cogging torque and the total torque waveforms of the analyzed AFPMMs with different magnets geometries have been studied and compared. The harmonic content of all these variables has been also analyzed. These analyses are carried out to find out the more suitable geometry for in-wheel applications and particularly to minimize the torque ripple of the AFPMM.

  • New mathematical model of an inverter-based generator for stability studies of microgrid Systems

     Andrade Rengifo, Fabio; Romeral Martinez, Jose Luis; Kampouropoulos, Konstantinos; Cusido Roura, Jordi
    International Conference on Power Engineering, Energy and Electrical Drives
    Presentation's date: 2013-05-15
    Presentation of work at congresses

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    A new mathematical model of a renewable generator, with a DC-AC interface, based on the concept of electrostatic machine is presented. This new model has a direct relationship between the DC and AC side. Moreover, it can be used for stability studies, taking into account the dynamics of the DC link and to find saturations and limits on the control signals.

  • A novel AC-AC converter based SiC for domestic induction cooking applications

     Salehifar, Mehdi; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicente Miguel; Romeral Martinez, Jose Luis
    IEEE Applied Power Electronics Conference and Exposition
    Presentation of work at congresses

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    This paper presents the analysis and design of a new high frequency ac-ac converter applied to domestic induction heating. The proposed topology uses only four switches to control power. Converter operation is same as a conventional class D inverter. Working above the resonant frequency, a sinusoidal input current and a unit power factor are obtained. To bring higher efficiency and power density, application of emerging SiC technology in proposed converter has been evaluated. The analytical and simulation results have been verified by means of a 380-W induction heating prototype.

  • Fault tolerant operation of a five phase converter for PMSM drives

     Salehifar, Mehdi; Salehi Arashloo Arashloo, Ramin; Moreno Eguilaz, Juan Manuel; Sala Caselles, Vicente Miguel; Romeral Martinez, Jose Luis
    IEEE Applied Power Electronics Conference and Exposition
    Presentation of work at congresses

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    In this paper a five phase fault tolerant converter is proposed for permanent magnet (PM) drives. The proposed configuration is an extension of conventional three phase double switch redundant topologies. In contrast to three phase systems,the proposed configuration has more flexibility and reliability regarding simultaneous faults in more than one phase. Different faulty cases are explained. Optimal reconfiguration strategies are derived under several faulty conditions. Design criteria are defined and a comparative loss analysis is conducted on converter behavior under various conditions. Simulation results are included to validate the theory.

  • Electrical and Magnetic Faults Diagnosis in Permanent Magnet Synchronous Motors  Open access

     Urresty Betancourt, Julio César
    Defense's date: 2012-09-21
    Department of Electronic Engineering, Universitat Politècnica de Catalunya
    Theses

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    Permanent magnet synchronous motors (PMSMs) are an alternative in critical applications where high-speed operation, compactness and high efficiency are required. In these applications it is highly desired to dispose of an on-line, reliable and cost-effective fault diagnosis method. Fault prediction and diagnosis allows increasing electric machines performance and raising their lifespan, thus reducing maintenance costs, while ensuring optimum reliability, safe operation and timely maintenance. Consequently this thesis is dedicated to the diagnosis of magnetic and electrical faults in PMSMs. As a first step, the behavior of a healthy machine is studied, and with this aim a new 2D finite element method (FEM) modelbased system for analyzing surface-mounted PSMSs with skewed rotor magnets is proposed. It is based on generating a geometric equivalent non-skewed permanent magnet distribution which accounts for the skewed distribution of the practical rotor, thus avoiding 3D geometries and greatly reducing the computational burden of the problem. To diagnose demagnetization faults, this thesis proposes an on-line methodology based on monitoring the zero-sequence voltage component (ZSVC). Attributes of the proposed method include simplicity, very low computational burden and high sensibility when compared with the well known stator currents analysis method. A simple expression of the ZSVC is deduced, which can be used as a fault indicator parameter. Furthermore, mechanical effects arising from demagnetization faults are studied. These effects are analyzed by means of FEM simulations and experimental tests based on direct measurements of the shaft trajectory through self-mixing interferometry. For that purpose two perpendicular laser diodes are used to measure displacements in both X and Y axes. Laser measurements proved that demagnetization faults may induce a quantifiable deviation of the rotor trajectory. In the case of electrical faults, this thesis studies the effects of resistive unbalance and stator winding inter-turn short-circuits in PMSMs and compares two methods for detecting and discriminating both faults. These methods are based on monitoring and analyzing the third harmonic component of the stator currents and the first harmonic of the ZSVC. Finally, the Vold-Kalman filtering order tracking algorithm is introduced and applied to extract selected harmonics related to magnetic and electrical faults when the machine operates under variable speed and different load levels. Furthermore, different fault indicators are proposed and their behavior is validated by means of experimental data. Both simulation and experimental results show the potential of the proposed methods to provide helpful and reliable data to carry out a simultaneous diagnosis of resistive unbalance and stator winding inter-turn faults.

  • Detection of demagnetization faults in surface-mounted permanent magnet synchronous motors by means of the zero-sequence voltage component

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Delgado Prieto, Miquel; Romeral Martinez, Jose Luis
    IEEE transactions on energy conversion
    Date of publication: 2012-03-01
    Journal article

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    This paper develops and analyzes an online methodology to detect demagnetization faults in surface-mounted permanent magnet synchronous motors. The proposed methodology, which takes into account the effect of the inverter that feeds the machine, is based on monitoring the zero-sequence voltage component of the stator phase voltages. The theoretical basis of the proposed method has been established. Attributes of the method presented here include simplicity, very low computational burden, and high sensibility. Since the proposed method requires access to the neutral point of the stator windings, it is especially useful when dealing with fault tolerant systems. A simple expression of the zero-sequence voltage component is deduced, which is proposed as a fault indicator parameter. Both simulation and experimental results presented in this paper show the potential of the proposed method to provide helpful and reliable data to carry out an online diagnosis of demagnetization failures in the rotor permanent magnets.

  • Load forecasting framework of electricity consumptions for an Intelligent Energy Management System in the user-side

     Cardenas Araujo, Juan Jose; Romeral Martinez, Jose Luis; Garcia Espinosa, Antonio; Andrade Rengifo, Fabio
    Expert systems with applications
    Date of publication: 2012-04
    Journal article

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  • Theoretical estimation of distorting effects by t rr of parasitic MOSFET-Diode in DCI-NPC audio power amplifiers

     Sala Caselles, Vicente Miguel; Romeral Martinez, Jose Luis
    IEICE electronics express
    Date of publication: 2012-03-25
    Journal article

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  • Application of the zero-sequence voltage component to detect stator winding inter-turn faults in PMSMs

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis
    Electric power systems research
    Date of publication: 2012-08
    Journal article

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    This paper develops and analyzes a methodology for detecting stator winding inter-turn faults in surface-mounted permanent magnet synchronous motors. The proposed methodology is based on monitoring the zero-sequence voltage component having into account the effects of the inverter that usually feeds the machine. The theoretical basis of such a method is established from the parametric model of the machine. Attributes of the method presented here include simplicity, high accuracy, low computational burden and high sensibility. Additionally, it is especially useful when dealing with fault tolerant systems. From this model the expression of the zero sequence voltage component is deduced, which is used to detect stator winding inter-turn faults. Both simulation and experimental results presented in this work show the potential of the proposed method to provide helpful and reliable data to carry out an online diagnosis of such faults.

  • Theoretical estimation of distorting effects by t(rr) of clamp diodes in DCI-NPC audio power amplifiers

     Sala Caselles, Vicente Miguel; Romeral Martinez, Jose Luis; Moreno Eguilaz, Juan Manuel
    IEICE electronics express
    Date of publication: 2012
    Journal article

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  • Evaluation of trr distorting effects reduction in DCI-NPC multilevel power amplifiers by using SiC diodes and MOSFET technologies

     Sala Caselles, Vicente Miguel; Resano Inza, Tomas; Romeral Martinez, Jose Luis; Moreno Eguilaz, Juan Manuel
    Audio Engineering Society
    Presentation's date: 2012-10-26
    Presentation of work at congresses

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    In the last decade, the Power Amplifier applications have used multilevel diode-clamped-inverter or neutral-point-clamped (DCI-NPC) topologies to present very low distortion at high power. In these applications a lot of research has been done in order to reduce the sources of distortion in the DCI-NPC topologies. One of the most important sources of distortion, and less studied, is the reverse recovery time (trr) of the clamp diodes and MOSFET parasitic diodes. Today, with the emergence of Silicon Carbide (SiC) technologies, these sources of distortion are minimized. This paper presents a comparative study and evaluation of the distortion generated by different combinations of diodes and MOSFETs with Si and SiC technologies in a DCI-NPC multilevel Power Amplifier in order to reduce the distortions generated by the non-idealities of the semiconductor devices.

    In the last decade, the Power Amplifier applications have used multilevel diode-clamped-inverter or neutral-point-clamped (DCI-NPC) topologies to present very low distortion at high power. In these applications a lot of research has been done in order to reduce the sources of distortion in the DCI-NPC topologies. One of the most important sources of distortion, and less studied, is the reverse recovery time (trr) of the clamp diodes and MOSFET parasitic diodes. Today, with the emergence of Silicon Carbide (SiC) technologies, these sources of distortion are minimized. This paper presents a comparative study and evaluation of the distortion generated by different combinations of diodes and MOSFETs with Si and SiC technologies in a DCI-NPC multilevel Power Amplifier in order to reduce the distortions generated by the non-idealities of the semiconductor devices.

  • New strategy to minimize dead-time distortion in DCI-NPC power amplifiers using COE-error injection

     Resano Inza, Tomas; Sala Caselles, Vicente Miguel; Romeral Martinez, Jose Luis; Moreno Eguilaz, Juan Manuel
    Audio Engineering Society
    Presentation's date: 2012-10-26
    Presentation of work at congresses

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    The DCI-NPC topology has become one of the best options to optimize energy efficiency in the world of high power and high quality amplifiers. This can use an analog PWM modulator that is sensitive to generate distortion or error, mainly for two reasons: Carriers Amplitude Error (CAE) and Carriers Offset Error (COE). Other main error and distortion sources in the system is the Dead-Time (td). This is necessary to guarantee the proper operation of the power amplifier stage so that errors and distortions originated by it are unavoidable. This work proposes a negative COE generation to minimize the distortion effects of td. Simulation and experimental results validates this strategy

    The DCI-NPC topology has become one of the best options to optimize energy efficiency in the world of high power and high quality amplifiers. This can use an analog PWM modulator that is sensitive to generate distortion or error, mainly for two reasons: Carriers Amplitude Error (CAE) and Carriers Offset Error (COE). Other main error and distortion sources in the system is the Dead-Time (td). This is necessary to guarantee the proper operation of the power amplifier stage so that errors and distortions originated by it are unavoidable. This work proposes a negative COE generation to minimize the distortion effects of td. Simulation and experimental results validates this strategy.

  • Influence of the prediction horizon length of a PHEV energy management on fuel consumption

     Bader, Benjamin; Torres Carbonell, Oriol; Ortega Redondo, Juan Antonio; Lux, G.; Romeral Martinez, Jose Luis
    International Electric Vehicle Symposium and Exhibition
    Presentation's date: 2012-05
    Presentation of work at congresses

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    he use of information about the future vehicle trajectory is especially advantageous for the energy management strategies of Plug-in Hybrid Electric Vehicles. This is based on the fact that for minimal fuel consumption the stored electric energy should be consumed until the end of the trip, if the trip length exceeds the electric range of the vehicle. Therefore, best results are achieved by an optimization of the torque distribution between both electric motor and combustion engine knowing the whole trajectory until the next use of a recharging station. Due to the long recharging times this means usually an optimization until the end of the trip. A drawback of such long predictive horizons is the high computation cost. Another is the increasing model uncertainty due to the use of simplified powertrain models for the prediction algorithm and also the reliability of the predicted trip information. Therefore, one aim is to reduce the prediction horizon as much as possible without increasing significantly the fuel consumption. To save computation cost of the optimization and decrease the influence of model uncertainties, in this paper an energy management for Plug-in HEV calculating the global optimum for the whole trip is compared to optimization with different prediction horizon lengths. To define the desired SOC at the end of the prediction horizon a linear reference SOC function is used. Depending on the chosen prediction length the trajectory is divided into several sections, each one standing for one prediction horizon. At the entrance to every section the energy management calculates the optimal torque set point for the whole next section (prediction horizon). In order to exclude the influence of the optimization algorithm, Dynamic Programming is used to calculate the global optimum.

  • Implementation of the Direct Torque Control (DTC) in current model, with current starting limiter

     Mino Aguilar, Gerardo; Muñoz Hernández, German Ardul; Romeral Martinez, Jose Luis; Cortez, Liliana; Saynes Torres, J.
    International Conference on Electrical Communications and Computers
    Presentation's date: 2012
    Presentation of work at congresses

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    This paper presents the scheme of Direct Torque Control (DTC) for induction motor drives, where flux and torque of the motor are estimated by the IM current model. Its scheme requires the knowledge of speed, rotor time constant and inductive parameters of the motor. The results prove the excellent characteristics for torque response and efficiency, which confirm the validity of this control scheme. Due to the rapid response offered by the DTC, this causes a high star current inversor protections activating. To resolve this, is presents the implementation of a closed loop of current vector the optimum switching table that limits the current and put into operation to the DTC. Experimental tests demonstrate effectiveness.

  • Access to the full text
    Simulación del proceso de emisión acústica. Generación de ondas elásticas transitorias en un engranaje bajo tensión  Open access

     Cobo Molina, Raul; Rezano Inza, Tomás; Riera Colom, Maria Dolores; Romeral Martinez, Jose Luis
    Reunión de Usuarios de SIMULIA
    Presentation's date: 2012-11-12
    Presentation of work at congresses

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    Con el objetivo de que el funcionamiento de una máquina sea el correcto es imperativo asegurar que existe un buen mantenimiento predictivo. Es conveniente tener un sistema inteligente y dispositivos capaces de detectar fallos en fases tempranas. Los fallos más comunes en máquinas industriales son todos aquellos relacionados con los sistemas de transmisión de potencia. La técnica de emisión acústica (EA) es el último enfoque para detectar e identificar defectos en rodamientos, cajas de cambio y uniones mecánicas. La emisión acústica (EA) es el fenómeno de generación de ondas elásticas transitorias en materiales bajo tensión. Cuando el material está sometido a un cierto nivel de tensión, una liberación rápida de energía de deformación tiene lugar en forma de ondas elásticas, las cuales pueden ser detectadas mediante transductores colocados en la pieza en cuestión. El objetivo de este trabajo es proporcionar una caracterización de las ondas elásticas que emanan de grietas localizadas entre el flanco y el valle de un engranaje. Las señales han sido registradas usando transductores colocados en la superficie del engranaje (a media distancia entre el eje y los dientes). El método de los elementos finitos ha sido utilizado para simular las ondas elásticas emitidas durante el crecimiento de las grietas. El modelo de simulación está basado en suposiciones elásticas y se ha llevado a cabo mediante Abaqus. Estos resultados han sido comparados con los resultados experimentales.

    In order to have a machine that functions well it is imperative to ensure that there is a good predictive maintenance. An intelligent system and devices able to detect the fault in its early stage is then convenient. The most common failures in industrial machines are those related to the power transmission systems. Acoustic Emission (AE) is the latest approach in detecting and identifying faults in bearings, gearboxes and mechanical couplings. Acoustic Emission (AE) is the phenomenon of transient elastic wave generation in materials under stress. When the material is subjected to stress at a certain level, a rapid release of strain energy takes place in the form of an elastic wave which can be detected by transducers placed on it. The objective of this work is to provide a characterization of elastic waves emanating from cracks located between the flank and the valley of a gear. The signals have been recorded using transducers attached to the surface of the gear (midway between the shaft and the teeth). FE modeling has been used to simulate the elastic waves emitted from fatigue crack growth. The model is based on linear elasticity assumptions and undertaken using Abaqus. These results have been compared with the experimental ones.

  • On the effect of accessible neutral point in fault tolerant five phase PMSM drives

     Salehi Arashloo Arashloo, Ramin; Salehifar, Mehdi; Romeral Martinez, Jose Luis
    Annual Conference of the IEEE Industrial Electronics Society
    Presentation's date: 2012-10
    Presentation of work at congresses

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    This study deals with the fault tolerant vector control strategies of a five-phase permanent-magnet (PM) machine. The analysis is focused on the effect of accessible neutral point under faulty conditions. Open circuit fault of one and two phases are considered, and proper control strategies are proposed to reduce the amplitude of currents in the remaining healthy phases. Simulations under both healthy and faulty conditions have been undertaken, and the effect of accessible neutral point on current amplitudes and torque ripple is evaluated.

  • Load forecasting in the user side using wavelet-ANFIS

     Giacometto Torres, Francisco; Cardenas Araujo, Juan Jose; Kampouropoulos, Konstantinos; Romeral Martinez, Jose Luis
    Annual Conference of the IEEE Industrial Electronics Society
    Presentation's date: 2012-10
    Presentation of work at congresses

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    At present, the intelligent energy management systems (IEMS) are used to maximiz the relation between productivity and cost using a variety of energy sources. Tn this work, we present a method of short-time load forecasting, using the ANFTS model and a component of preprocessing based in the discrete wavelet transform; the models was implemented in the user-side, analyzing real data of a factory in order to test the proposed algorithm

  • Comparison of different hybrid electric vehicles concepts in terms of consumption and efficiency

     Torres Carbonell, Oriol; Bader, Benjamin; Romeral Martinez, Jose Luis; Lux, G.; Ortega Redondo, Juan Antonio
    International Electric Vehicle Symposium and Exhibition
    Presentation's date: 2012-05
    Presentation of work at congresses

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    The objective of this paper is to compare the most common HEV power train structures. As a first step, forward and backward models of these vehicle concepts are implemented using Modelica/Dymola in order to evaluate and compare the energy consumption. Taking into account fuel/electrical consumption and the losses in the powertrain components, a comparison of two different alternatives of Hybrid Electric Vehicle models (parallel structure and Range Extender) are presented in this publication. To simulate these models using different driving cycles, a rule-based operating strategy is implemented. As a second step, a Dynamic Programming (DP) based algorithm is applied to these models. This algorithm is used to determine the optimal fuel consumption for given driving cycles. A comparison of the DP results and rule-based results is carried out to evaluate the potential improvement that is possible to achieve optimizing the energy management strategy and the size of the powertrain components.

  • Modeling and studying of power flow in a parking lot with plug-in vehicles and the impact in the public utility

     Andrade Rengifo, Fabio; Cardenas Araujo, Juan Jose; Romeral Martinez, Jose Luis; Cusido Roura, Jordi
    IEEE Innovative Smart Grid Technologies Conference Europe
    Presentation's date: 2012
    Presentation of work at congresses

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  • Analysis of demagnetization faults in surface-mounted permanent magnet synchronous with inter-turns and phase-to-ground short-circuits

     Urresty Betancourt, Julio César; Riba Ruiz, Jordi Roger; Romeral Martinez, Jose Luis; Saavedra Ordoñez, Harold
    International Conference on Electrical Machines
    Presentation's date: 2012-09-03
    Presentation of work at congresses

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    Demagnetization faults are troublesome in permanent magnet synchronous motors since they may greatly reduce their performance and efficiency. Additionally, the temperature of the magnets deeply influences the remanent flux density. Hence, the temperature may have a demagnetization effect on the magnets. This work studies the behavior of a surface-mounted permanent magnet synchronous motor running under inter-turn and phase-to-ground short-circuits faults. Concretely, the temperature increase of such faults and a potential reversible or irreversible demagnetization of the rotor magnets are analyzed. The analysis is based on 2D FEM simulations which includes rotor magnet skew. The simulations conducted in this work clearly show that inter-turn faults do not lead to irreversible demagnetization. However, in case of a phase-to-ground short-circuit an irreversible demagnetization may take place instantaneously

  • Clamping diode caused distortion in multilevel NPC Full-Bridge audio power amplifiers

     Sala Caselles, Vicente Miguel; Salehi Arashloo Arashloo, Ramin; Moreno Eguilaz, Juan Manuel; Salehifar, Mehdi; Romeral Martinez, Jose Luis
    IEEE International Conference on Industrial Electronics
    Presentation's date: 2012-10
    Presentation of work at congresses

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    This paper presents a study and analysis of the distorting effects of clamped diodes in multilevel DCI-NPC topology applied to high power and high quality audio-amplifier. The main distorting sources of error are characterized, which are due to the clamped-diodes non-idealities; and they are evaluated for typical commercial diodes values and working conditions. Through this study the distorting contribution of each non-ideality can be quantified, and the influence of the system operating parameters, such as reactive current angle and modulation index, are highlighted. Finally, it is presented the table of optimal parameters that a commercial diode should have to ensure proper operation of the amplifier under rated power and quality specification

    This paper presents a study and analysis of the distorting effects of clamped diodes in multilevel DCI-NPC topology applied to high power and high quality audio-amplifier. The main distorting sources of error are characterized, which are due to the clamped-diodes non-idealities; and they are evaluated for typical commercial diodes values and working conditions. Through this study the distorting contribution of each non-ideality can be quantified, and the influence of the system operating parameters, such as reactive current angle and modulation index, are highlighted. Finally, it is presented the table of optimal parameters that a commercial diode should have to ensure proper operation of the amplifier under rated power and quality specification.