Cette thèse propose des approches neuromimétiques d'identification et de commande avec des applications directes au Filtre Actif Parallèle (FAP) et au Moteur Synchrone à Aiment Permanent (MSAP). Une structure neuronale complète a été développée pour réaliser toutes les fonctionnalités d'un FAP pour compenser des harmoniques de courant. La phase instantanée et les composantes symétriques d'un système triphasé de tensions ou de courants ont été estimées avec une boucle à verrouillage de phase neuronale. L'identification des harmoniques de courant a été réalisée avec des réseaux de neurones de type Adaline opérant dans les différents repères. Plusieurs schémas de commande ont été développés pour réinjecter les courants de compensation à l'aide d'un onduleur. Ils sont basés sur des techniques neuromimétiques, sur la logique floue, ou sur leur association. Une approche neuronale a été développée pour commander une MSAP à distribution quelconque avec des contraintes prédéterminées réduisant les ondulations du couple. Elle consiste en des schémas de commande directe en couple ou en vitesse pour obtenir les courants statoriques optimaux qui donnent exactement le couple électromagnétique (ou la vitesse) désiré et qui réduisent au maximum les pertes par effet Joule. Ces commandes intègrent deux blocs neuronaux, l'un dédié au calcul des courants optimaux et l'autre pour assurer leur génération à travers un onduleur de tension. Toutes les approches neuromimétiques ont été validées par des tests de simulation et des essais expérimentaux. Des comparaisons avec les méthodes de commande classique démontrent des caractéristiques supérieures en termes de performance et de robustesse. / This thesis proposes Artificial Neural Networks (ANN) approaches for the identification and the control of an Active Power Filter (APF) and a Permanent-Magnet Synchronous Motor (PMSM). A completed neural architecture was developed for an APF for harmonic currents compensation. The instantaneous phase and the symmetrical components of a three-phase voltage or current were estimated with a neural phase Jock loop. The harmonic terms were identified by Adaline neural networks that estimate the instantaneous powers within different reference frames. Several intelligent techniques, based on neural networks, fuzzy logic or their association, were developed to control the inverter used to inject the harmonic currents phase-opposite. An original neural approach was also carried out for reducing the torque ripple of a non-sinusoidal PMSM. It consists in a direct torque or in a speed control schemes that elaborate the optimal stator currents which exactly give a desired electromagnetic torque or speed and which minimize the ohmic losses. The control schemes integrate two neural networks, one to calculate the optimal currents and one to ensure their generation through an inverter. The neural network approaches were all evaluated by simulated and experimental tests. The results confirm their excellent characteristics in terms of both performance and robustness. Comparisons with conventional methods prove their superiority.

The intentions of the so-called "More Electrical Aircraft" (MEA) are higher efficiency and lower weight. A main topic here is the application of electrical instead of hydraulical, pneumatical and mechanical systems. The necessary power electronic devices have intermediate DC-links, which are typically supplied by a three-phase system with active B6 and passive B12 rectifiers. A possible alternative is the B6 diode bridge in combination with an active power filter (APF). Due to the parallel arrangement, the APF offers a higher power density and is able to compensate for harmonics from several devices. The use of the diode bridge rectifier alone is not permitted due to the highly distorted phase current. The following investigations are dealing with the development of an active power filter for a three-phase supply with variable frequency from 360 to 800 Hz. All relevant components such as inductors, EMC-filters, power modules and DC-link capacitor are designed. A particular focus is put on the customized power module with SiC-MOSFETs and SiC-diodes, which is characterized electrically and thermally. The maximum supply frequency slope has a value of 50 Hz/ms, which requires a high dynamic and robustness on the control algorithm. Furthermore, the content of 5th and 7th harmonics must be reduced to less than 2 %, which demands a high accuracy. To cope with both requirements, a two-stage filter algorithm is developed and implemented in two independent signal processors. Simulations and laboratory experiments confirm the performance and robustness of the control algorithm. This work comprehensively presents the design of aerospace rectifiers. The results were published in conferences and patents. / Hauptziele des sogenannten "More Electrical Aircraft" (MEA) sind Effizienzerhöhung und Gewichtseinsparung. Ein Schwerpunkt hierbei ist die Nutzung von elektrischen statt hydraulischen, pneumatischen und mechanischen Systemen. Die notwendigen Leistungselektroniken haben DC-Zwischenkreise, welche mittels aktiven B6 und passiven B12 Gleichrichtern aus dem Dreiphasennetz gespeist werden. Eine mögliche Alternative ist die B6 Diodenbrücke in Kombination mit einem aktiven Netzfilter, welcher aufgrund der parallelen Anordnung eine höhere Leistungsdichte aufweist und darüber hinaus mehrere Geräte gleichzeitig entstören kann. Die alleinige Nutzung einer Diodenbrücke ist aufgrund des hohen Anteils von Stromharmonischen nicht zulässig. Diese Arbeit beschäftigt sich mit der Entwicklung eines aktiven Filters für ein Dreiphasensystem mit variabler Frequenz von 360 bis 800 Hz. Es werden alle relevanten Bauteile wie Induktivitäten, EMV-Filter, Leistungsmodule und Zwischenkreiskondensator ausgelegt. Besonderes Augenmerk liegt auf dem kundenspezifischen Modul mit SiC-Dioden und SiCMOSFETs, welches vollständig elektrisch und thermisch charakterisiert wird. Die Änderung der Netzfrequenz beträgt bis zu 50 Hz/ms, was eine hohe Dynamik und Robustheit von der Filterregelung verlangt. Weiterhin ist im statischen Fall eine hohe Genauigkeit gefordert, da die 5. und 7. Harmonische auf unter 2% geregelt werden müssen. Um beiden Anforderungen gerecht zu werden, wird ein zweistufiger Regelungsalgorithmus entwickelt der auf zwei digitalen Signalprozessoren implementiert wird. Simulationen und Labormessungen bestätigen die Robustheit des Regelungskonzeptes. Diese Arbeit stellt umfassend die Entwicklung von Luftfahrtgleichrichtern dar. Die Ergebnisse wurden in Konferenzen und Patenten veröffentlicht.

Resumo: Este trabalho apresenta uma nova proposta para sistema de refrigeração com controle dinâmico de temperatura, operando com estrutura de compressor aberto, acionado por motor de indução trifásico com velocidade variável, e estágio de entrada retificador com correção ativa do fator de potência. O estágio de entrada é composto por um retificador Boost monofásico com elevado fator de potência, com duas células entrelaçadas, operando no modo de condução crítica, empregando técnica de comutação não dissipativa e controlado por dispositivo FPGA, associado a um estágio de saída inversor de dois níveis convencional trifásico à IGBT, o qual é controlado por um Processador Digital de Sinais (DSP - Digital Signal Processor). A técnica de comutação não dissipativa para o estágio de entrada é baseada em células ZCS (Zero-current-switching). As principais características do retificador incluem a redução da ondulação da corrente de entrada, redução da ondulação da tensão de saída retificada, utilização de componentes com reduzidos esforços, reduzido volume do filtro de entrada para Interferências Eletromagnéticas (EMI - Electromagnetic Interference), elevado Fator de Potência (FP) e reduzida Distorção Harmônica Total (DHT) da corrente de entrada, atendendo os limites da norma IEC61000-3-2. O controle digital para o estágio de saída inversor foi desenvolvido usando duas diferentes técnicas, incluindo a técnica convencional controle escalar Volts/Hertz (V/Hz) e o controle Vetorial com Orientação pelo Fluxo do estator, com o propósito de verificar a aplicabilidade e a performance dos controles digitais propostos, para o controle contínuo da temperatura, aplicados a um protótipo de sistema de refrigeração. / Abstract: This work presents a new proposal for refrigeration systems with dynamic control of temperature, working with structure of open compressor, driving a three-phase induction motor with variable speed, and input rectifier with active power factor correction. The proposed system is composed of a single-phase high-power-factor boost rectifier, with two cells in interleaved connection, operating in critical conduction mode, and employing a softswitching technique, controlled by a Field Programmable Gate Array (FPGA), associated with a conventional three-phase IGBT bridge inverter (VSI - Voltage Source Inverter), controlled by a Digital Signal Processor (DSP). The soft-switching technique for the input stage is based on zero-current-switching (ZCS) cells. The rectifier’s features include reduction in input current ripple, reduction in output voltage ripple, use of low stress devices, low volume for the EMI input filter, high input power factor (PF), and low total harmonic distortion (THD) in the input current, in compliance with the IEC61000-3-2 standards. The digital controller for the output stage inverter has been developed using two different techniques, the conventional Voltage-Frequency control (scalar V/Hz control), and a simplified stator oriented vector control, in order to verify the feasibility and performance of the proposed digital controls, for continuous temperature control, applied at a refrigerator prototype. / Orientador: Carlos Alberto Canesin / Coorientador: Flávio Alessandro Serrão Gonçalves / Banca: Fabio Toshiaki Wakabayashi / Banca: João Onofre Pereira Pinto / Mestre

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-02-05T17:06:52Z No. of bitstreams: 1 guilhermemarciosoares.pdf: 5349685 bytes, checksum: 1085aed638a3213e03844d5e5e68f7d1 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-02-26T11:52:22Z (GMT) No. of bitstreams: 1 guilhermemarciosoares.pdf: 5349685 bytes, checksum: 1085aed638a3213e03844d5e5e68f7d1 (MD5) / Made available in DSpace on 2016-02-26T11:52:22Z (GMT). No. of bitstreams: 1 guilhermemarciosoares.pdf: 5349685 bytes, checksum: 1085aed638a3213e03844d5e5e68f7d1 (MD5) Previous issue date: 2014-06-25 / Este trabalho propõe um sistema inteligente de iluminação pública utilizando diodos emissores de luz (LEDs). Neste âmbito, é proposta uma topologia para o acionamento dos LEDs com controle de intensidade luminosa. Além disso, funções adicionais são propostas de modo a expandir o conjunto de funcionalidades da luminária. Para o acionamento dos LEDs foi desenvolvido um conversor baseado na topologia Ćuk operando em modo de condução descontínuo (DCM) com um interruptor estático em série com a carga, sendo uma solução para o acionamento de LEDs de estágio único. Deste modo, este conversor foi projetado para desempenhar simultaneamente as funções de correção do fator de potência e controle da potência na carga. Através da análise da resposta fotométrica dos diodos emissores de luz perante ondulações de baixa frequência em sua corrente, foi possível criar uma metodologia de projeto que evita o uso de capacitores eletrolíticos no circuito de acionamento dos LEDs, aumentando assim a confiabilidade do sistema. A modelagem e o controle do conversor também foram feitas e estão mostradas no trabalho. De modo a controlar e gerenciar o sistema eletrônico da luminária, foi proposta uma arquitetura baseada no microcontrolador TM4C123GE6PM. Este sistema digital é responsável ainda por promover outras funcionalidades como controle automático de intensidade luminosa, proteção do circuito e ainda monitoramento de parâmetros de qualidade de energia da tensão de entrada do conversor, tais como afundamentos e elevações. A fim de avaliar experimentalmente o sistema proposto, foram desenvolvidos um programa de computador capaz de gerenciar as funcionalidades da luminária e um protótipo de 70W deste equipamento. Os resultados experimentais obtidos mostraram um bom desempenho tanto do circuito de acionamento dos LEDs, como das funcionalidades da luminária. / This paper proposes a smart lighting system based on light-emitting diodes (LEDs) for street lighting applications. In this context, a power converter with dimming capability was designed. Furthermore, additional functions are proposed in order to expand the feature set of the luminaire. To drive the LEDs, a topology based on Ćuk converter operating in discontinuous conduction mode (DCM) with an electronic switch in series with the load was proposed. This converter was designed to perform simultaneously the functions of power factor correction and power control, being a single-stage LED driver solution. By analyzing the LEDs photometric response due to low-frequency current ripple, a design methodology that avoids the use of electrolytic capacitors in the proposed converter was developed. The modeling and control of the converter were also done in order to ensure that the system is always operating within the desired specifications. To control and manage the electronic system of the luminaire, it was developed an architecture based on the microcontroller TM4C123GE6PM. Beside the aforementioned functions, this digital system was designed aiming the promotion of other features, such as automatic dimming, protection of the driver and even monitoring some power quality parameters related to the input voltage, such as sags and swells. In order to experimentally evaluate the proposed system, a software, able to manage the luminaire functionalities, and a 70W prototype were built. The experimental results demonstrated a good performance of the LED driver as well as the functionalities of the proposed luminaire.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-12T12:29:15Z No. of bitstreams: 1 pedrosantosalmeida.pdf: 11306492 bytes, checksum: 80bd2f9ab4af41e3889b7bc91e4391b9 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:48:06Z (GMT) No. of bitstreams: 1 pedrosantosalmeida.pdf: 11306492 bytes, checksum: 80bd2f9ab4af41e3889b7bc91e4391b9 (MD5) / Made available in DSpace on 2016-07-13T16:48:06Z (GMT). No. of bitstreams: 1 pedrosantosalmeida.pdf: 11306492 bytes, checksum: 80bd2f9ab4af41e3889b7bc91e4391b9 (MD5) Previous issue date: 2012-03-23 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho apresenta um estudo acerca da alimentação de diodos emissores de luz (LEDs) a partir da rede elétrica empregando conversores eletrônicos com correção do fator de potência. O estudo visa o desenvolvimento de um conversor que pode ser aplicado em iluminação pública, que atenda às demandas típicas de alto fator de potência, alta eficiência, reduzido número de componentes, baixa distorção harmônica da corrente de entrada e possa atingir uma elevada vida útil, através da substituição de capacitores eletrolíticos no circuito de potência por capacitores de filme. É proposta uma nova topologia de conversor para implementar tal acionamento, baseado em uma integração entre dois estágios, que passam a compartilhar um único interruptor estático. Os conversores SEPIC e buck-boost operando em modo de condução descontínua (DCM) são escolhidos para compor cada um destes estágios, atuando o primeiro na correção do fator de potência e o segundo na regulação de corrente na carga. Uma metodologia de projeto que visa excluir os capacitores eletrolíticos é desenvolvida, partindo de dados fotométricos que permitem aplicar nos LEDs uma ondulação limite de 50% em amplitude, sem causar prejuízos ao seu desempenho fotométrico. Um protótipo de 70 W é apresentado, cujos resultados experimentais demonstram alto fator de potência (0,998), baixa distorção harmônica de corrente (3,2%) e alta eficiência (90,2%), enquanto empregando somente capacitores de filme metalizado, de longa vida útil, no circuito de potência. Uma abordagem das possibilidades de se implementar um controlador digital para o novo conversor proposto é feita, partindo de um modelo de pequenos sinais para o conversor operando em DCM. / This work presents a study regarding the feeding of light-emitting diodes (LEDs) from mains (grid power) employing electronic drivers with power factor correction. The study aims the development of an LED driver which can be applied to public and street lighting, complying with the typical demands of high power factor, high efficiency, reduced component count, low total harmonic distortion (THD) of input current and which can attain long lifespan, through the substitution of electrolytic capacitors within the power circuit by film capacitors. It is proposed a new converter topology to implement such driver, based on an integration between two stages which share a common static power switch. The SEPIC and buck-boost converters operating in discontinuous conduction mode (DCM) are chosen to make up each of these two stages, the first acting as a power factor corrector and the second as a load currentcontrolling stage. A design methodology which aims the exclusion of electrolytic capacitors is developed, stemming from photometric data which allow the LEDs to be operated with current ripples up to 50% in amplitude, without causing any harm to their photometric performance. A 70 W prototype is presented, whose experimental results demonstrate high power factor (0.998), low current harmonic distortion (3.2%) and high efficiency (90.2%), while employing only long-life metallised-film capacitors on the power circuit. An approach to the possibilities of implementing a digital controller for the proposed novel converter is done, starting from a small-signal model for the converter operating in DCM.

Esta tesis doctoral trata acerca de los sistemas de compensación activos de conexión en paralelo utilizados para la mejora de la calidad del suministro eléctrico, y de la eficiencia energética en las redes eléctricas de distribución y en las instalaciones, a cuatro hilos. En la presente tesis se desarrolla un nuevo filtro o compensador activo de potencia con la capacidad de seleccionar los fenómenos a compensar, incluyéndose además algunas propuestas que, aplicadas a estos sistemas de compensación, permiten mejorar las prestaciones finales obtenidas. Se presentan las estrategias de compensación global más utilizadas en compensadores activos y se propone un método de compensación global basado en la norma IEEE Std. 1459-2000. Se realiza un estudio comparativo de las diferentes estrategias de compensación global. Para la obtención de un compensador selectivo, se proponen dos métodos diferentes para la descomposición de las corrientes de carga y la obtención de las corrientes de compensación. El primer método está basado en la utilización de las conductancias por fase y la conductancia equivalente del sistema trifásico. El segundo se basa en la descomposición de potencias propuesta en la IEEE Std. 1459-2000. Se presenta un análisis de cada uno de los métodos propuestos. Se presenta el análisis del sistema completo para la implementación del compensador selectivo propuesto. El sistema de control incluye, la utilización de la técnica de la ventana deslizante para la obtención de las corrientes de referencia, el desarrollo de un regulador de corriente de bajo coste computacional, el diseño del regulador para el control del bus dc y el desarrollo de un nuevo modulador vectorial tridimensional 3D-3B SVPWM. Finalmente, se presentan los resultados de simulación y experimentales del sistema de compensación diseñado, para diferentes tipos de cargas y condiciones de alimentación. Parte de estos resultados han sido presentados, entre otras, en las siguientes publicaciones: " S. O / Orts Grau, S. (2008). Sistema de compensación mediante filtro activo de potencia con sistema de obtención de las corrientes de referencia selectivo utilizando control 3D-3B SVPWM de la etapa de potencia. Aplicación a sistemas industriales a 4 hilos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/3797 / Palancia

Cette thèse présente un modèle unique du MASG (Modèle d’Architecture du Smart Grid) en considérant l 'état de l’art des différentes directives de recherche du smart grid. Le système hybride de génération d'énergie active marine-hydrogène a été modélisé pour représenter la couche de composants du MASG. Le système intègre l'électrolyseur à membrane d’échange de proton (à l’échelle de méga watt) et les systèmes de piles à combustible en tant que composants principaux du bilan énergétique. La batterie LiFePO4 est utilisée pour couvrir la dynamique rapide de l'énergie électrique. En outre, la thèse analyse le système de gestion de l'énergie centralisé et décentralisé. Le système multi-agents représente le paradigme du système décentralisé. La plate-forme JADE est utilisée pour développer le système multi-agents, en raison de son domaine d'application général, de ses logiciels à licence libre, de son interface avec MATLAB et de sa calculabilité avec les standards de la Fondation des Agents Physiques Intelligentes. Le système de gestion d'énergie basé sur JADE équilibre l'énergie entre la génération (système de conversion d'énergie marine-courant) et la demande (profil de charge résidentielle) pendant les modes de fonctionnement autonome et connecté au réseau. Le modèle proposé du MASG peut être considéré comme une étude de cas pilote qui permet l'analyse détaillée et les applications des différentes directions de recherche du smart grid. / This thesis presents a unique model of the SGAM (Smart Grid Architecture Model) with considering the state of the art of the different research directions of the smart grid and. The hybrid marine-hydrogen active power generation system has been modeled to represent the component layer of the SGAM. The system integrates the MW scale PEM electrolyzer and fuel cell systems as the main energy balance components. The LiFePO4 battery is used to cover the fast dynamics of the electrical energy. Moreover, the thesis analyzes the centralized and the decentralized energy management system. The MAS (Multi-Agent Systems) represents the paradigm of the decentralized system. The JADE platform is used to develop the MAS due to its general domain of application, open source and free license software, interface with MATLAB and the computability with the FIPA (Foundation of Intelligent Physical Agent) standards. The JADE based energy management system balances the energy between the generation (marine-current energy conversion system) and the demand side (residential load profile) during the stand-alone and the grid-connected modes of operation. The proposed model of the SGAM can be considered as a pilot case study that enables the detailed analysis and the applications of the different smart grid research directions.

De nos jours, la durée de vie des modules d’électronique de puissance est désormais limitée par les technologies standards de conditionnement, telles que le câblage par fils et le brasage. Ainsi une optimisation des technologies actuellement employées n’est pas suffisante pour satisfaire les futures exigences de fiabilité. Pour dépasser ces limites, un nouveau module de puissance remplaçant les fils de connexion par des clips en cuivre a été développé. Ce design innovant vise à améliorer la fiabilité du module puisqu’il empêche la dégradation des fils de connexion, constituant bien souvent la principale source de défaillance. La contrepartie de ce gain de fiabilité réside dans la complexification de la structure interne du module. En effet, l’emploi d’un clip en cuivre nécessite une brasure supplémentaire fixant le clip à la puce. Ainsi, le comportement thermomécanique et les différents modes de rupture auxquels le composant est soumis lors de son utilisation doivent être caractérisés. Cette étude utilise la simulation numérique pour analyser avec précision le comportement de chaque couche de matériaux lors des cycles actifs de puissance. De plus, une étude de sensibilité à la fois expérimentale et numérique concernant les paramètres de tests est réalisée. Les zones critiques du module ainsi que les combinaisons critiques des paramètres de tests pour les différents modes de rupture sont mis en évidence. Par ailleurs, une analyse en mécanique de la rupture est conduite et la propagation des fissures à différentes zones clés est analysée en fonction des différents paramètres de tests. Les résultats obtenus permettent la définition de modèles de prédiction de durée de vie. / Today a point has been reached where safe operation areas and lifetimes of power modules are limited by the standard packaging technologies, such as wire bonding and soft soldering. As a result, further optimization of used technologies will no longer be sufficient to meet future reliability requirements. To surpass these limits, a new power module was designed using Cu clips as interconnects instead of Al wire bonds. This new design should improve the reliability of the module as it avoids wire bond fatigue failures, often the root cause of device failures. The counterpart for an improved reliability is a quite complicated internal structure. Indeed, the use of a Cu clip implies an additional solder layer in order to fix the clip to the die. The thermo-mechanical behavior and failure mechanisms of such a package under application have to be characterized. The present study takes advantage of numerical simulations to precisely analyze the behavior of each material layer under power cycling. Furthermore an experimental and numerical sensitivity study on tests parameters is conducted. Critical regions of the module are pointed out and critical combinations of tests parameters for different failure mechanisms are highlighted. Then a fracture mechanics analysis is performed and the crack growth at different locations is analyzed in function of different tests parameters. Results obtained enable the definition of lifetime prediction models.

The intentions of the so-called "More Electrical Aircraft" (MEA) are higher efficiency and lower weight. A main topic here is the application of electrical instead of hydraulical, pneumatical and mechanical systems. The necessary power electronic devices have intermediate DC-links, which are typically supplied by a three-phase system with active B6 and passive B12 rectifiers. A possible alternative is the B6 diode bridge in combination with an active power filter (APF). Due to the parallel arrangement, the APF offers a higher power density and is able to compensate for harmonics from several devices. The use of the diode bridge rectifier alone is not permitted due to the highly distorted phase current. The following investigations are dealing with the development of an active power filter for a three-phase supply with variable frequency from 360 to 800 Hz. All relevant components such as inductors, EMC-filters, power modules and DC-link capacitor are designed. A particular focus is put on the customized power module with SiC-MOSFETs and SiC-diodes, which is characterized electrically and thermally. The maximum supply frequency slope has a value of 50 Hz/ms, which requires a high dynamic and robustness on the control algorithm. Furthermore, the content of 5th and 7th harmonics must be reduced to less than 2 %, which demands a high accuracy. To cope with both requirements, a two-stage filter algorithm is developed and implemented in two independent signal processors. Simulations and laboratory experiments confirm the performance and robustness of the control algorithm. This work comprehensively presents the design of aerospace rectifiers. The results were published in conferences and patents. / Hauptziele des sogenannten "More Electrical Aircraft" (MEA) sind Effizienzerhöhung und Gewichtseinsparung. Ein Schwerpunkt hierbei ist die Nutzung von elektrischen statt hydraulischen, pneumatischen und mechanischen Systemen. Die notwendigen Leistungselektroniken haben DC-Zwischenkreise, welche mittels aktiven B6 und passiven B12 Gleichrichtern aus dem Dreiphasennetz gespeist werden. Eine mögliche Alternative ist die B6 Diodenbrücke in Kombination mit einem aktiven Netzfilter, welcher aufgrund der parallelen Anordnung eine höhere Leistungsdichte aufweist und darüber hinaus mehrere Geräte gleichzeitig entstören kann. Die alleinige Nutzung einer Diodenbrücke ist aufgrund des hohen Anteils von Stromharmonischen nicht zulässig. Diese Arbeit beschäftigt sich mit der Entwicklung eines aktiven Filters für ein Dreiphasensystem mit variabler Frequenz von 360 bis 800 Hz. Es werden alle relevanten Bauteile wie Induktivitäten, EMV-Filter, Leistungsmodule und Zwischenkreiskondensator ausgelegt. Besonderes Augenmerk liegt auf dem kundenspezifischen Modul mit SiC-Dioden und SiCMOSFETs, welches vollständig elektrisch und thermisch charakterisiert wird. Die Änderung der Netzfrequenz beträgt bis zu 50 Hz/ms, was eine hohe Dynamik und Robustheit von der Filterregelung verlangt. Weiterhin ist im statischen Fall eine hohe Genauigkeit gefordert, da die 5. und 7. Harmonische auf unter 2% geregelt werden müssen. Um beiden Anforderungen gerecht zu werden, wird ein zweistufiger Regelungsalgorithmus entwickelt der auf zwei digitalen Signalprozessoren implementiert wird. Simulationen und Labormessungen bestätigen die Robustheit des Regelungskonzeptes. Diese Arbeit stellt umfassend die Entwicklung von Luftfahrtgleichrichtern dar. Die Ergebnisse wurden in Konferenzen und Patenten veröffentlicht.

This research presents a Hybrid Particle Swarm Optimization with Bat Algorithm (HPSOBA) based approach to solve Optimal Reactive Power Dispatch (ORPD) problem. The primary objective of this project is minimization of the active power transmission losses by optimally setting the control variables within their limits and at the same time making sure that the equality and inequality constraints are not violated. Particle Swarm Optimization (PSO) and Bat Algorithm (BA) algorithms which are nature-inspired algorithms have become potential options to solving very difficult optimization problems like ORPD. Although PSO requires high computational time, it converges quickly; while BA requires less computational time and has the ability of switching automatically from exploration to exploitation when the optimality is imminent. This research integrated the respective advantages of PSO and BA algorithms to form a hybrid tool denoted as HPSOBA algorithm. HPSOBA combines the fast convergence ability of PSO with the less computation time ability of BA algorithm to get a better optimal solution by incorporating the BA’s frequency into the PSO velocity equation in order to control the pace. The HPSOBA, PSO and BA algorithms were implemented using MATLAB programming language and tested on three (3) benchmark test functions (Griewank, Rastrigin and Schwefel) and on IEEE 30- and 118-bus test systems to solve for ORPD without DG unit. A modified IEEE 30-bus test system was further used to validate the proposed hybrid algorithm to solve for optimal placement of DG unit for active power transmission line loss minimization. By comparison, HPSOBA algorithm results proved to be superior to those of the PSO and BA methods. In order to check if there will be a further improvement on the performance of the HPSOBA, the HPSOBA was further modified by embedding three new modifications to form a modified Hybrid approach denoted as MHPSOBA. This MHPSOBA was validated using IEEE 30-bus test system to solve ORPD problem and the results show that the HPSOBA algorithm outperforms the modified version (MHPSOBA). / Electrical and Mining Engineering / M. Tech. (Electrical Engineering)