<p>Low-sensitivity switched capacitor filters imitating 'R','L' and 'C' can be built by means of capacitances, ordinary switches and voltage inverter switches (VIS). These structures carry the inherent bilinear transformation of their doubly resistively terminated ladder reference filters. This one to one correspondence between the 's-domain' and the 'z-domain' results in the Nyquist criterion being the only limitation on the sampling frequency. This eliminates the necessity for oversampling and VIS filters can be designed for high operating rates.</p><p>Filters based on VIS principle were analysed in previous literatures in the 'phi-domain'. In this thesis work, a successful attempt has been made to formulate an analysis procedure for discrete-time filters based on VIS principle in the 'z-domain'. Significant details have been brought out in comparison with the respective reference filter. A fifth-order lowpass filter has been designed and implemented to exhibit the closeness to the bilinearly transformed continuous-time reference filter. Settling time analysis has been done to justify the need for filters using VIS principle as compared to the filters employing integrator based switched capacitor filter. It is shown that VIS filter can be made to settle within half the period required for a conventional integrator based switched capacitor filter.</p>

Low-sensitivity switched capacitor filters imitating 'R','L' and 'C' can be built by means of capacitances, ordinary switches and voltage inverter switches (VIS). These structures carry the inherent bilinear transformation of their doubly resistively terminated ladder reference filters. This one to one correspondence between the 's-domain' and the 'z-domain' results in the Nyquist criterion being the only limitation on the sampling frequency. This eliminates the necessity for oversampling and VIS filters can be designed for high operating rates. Filters based on VIS principle were analysed in previous literatures in the 'phi-domain'. In this thesis work, a successful attempt has been made to formulate an analysis procedure for discrete-time filters based on VIS principle in the 'z-domain'. Significant details have been brought out in comparison with the respective reference filter. A fifth-order lowpass filter has been designed and implemented to exhibit the closeness to the bilinearly transformed continuous-time reference filter. Settling time analysis has been done to justify the need for filters using VIS principle as compared to the filters employing integrator based switched capacitor filter. It is shown that VIS filter can be made to settle within half the period required for a conventional integrator based switched capacitor filter.

Made available in DSpace on 2015-05-08T14:57:17Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2400808 bytes, checksum: 3c7c682278f78e771b9fee7c273a134b (MD5) Previous issue date: 2013-10-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work presents a technique to suppress saturation in series transformers applied to dynamic voltage restorer (DVR) systems. The technique consists in correcting the voltages which are injected through the transformers into the power system to compensate voltage sags. The presented method ensures complete elimination of the DC flux-linkage or shifts the flux-linkage curve, restricting their AC amplitude, so that the flux level does not exceed the limits of the transformer, preventing it works in the saturation region. The validation of this method will be realized from simulations and experimental results. / Este trabalho apresenta uma técnica para evitar a saturação dos transformadores de tensão em série aplicados em um restaurador dinâmico de tensão (DVR). A técnica consiste em alterar as tensões que são injetadas através dos transformadores para compensar afundamentos de tensão no sistema de potência. O método apresentado assegura uma eliminação completa do fluxo c.c. ou desloca a curva de fluxo, restringido sua amplitude c.a., de maneira que o nível de fluxo não exceda os limites do transformador, evitando que o mesmo trabalhe na região de saturação. A validação deste método será realizada a partir de simulações e resultados experimentais.

Orientadores: Jose Antenor Pomilio, Saulo Finco / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-09T03:34:05Z (GMT). No. of bitstreams: 1 Mioni_DanielPasti_M.pdf: 1903299 bytes, checksum: 7343c6fb1cd22aa8df8654d5b9b51852 (MD5) Previous issue date: 2007 / Resumo: Desenvolvemos um amplificador de áudio classe D baseado em moduladores S-?, destinado a aparelhos auditivos, a maioria dos quais utiliza baterias de 1,1V e necessita ter baixo consumo de corrente. Neste trabalho os amplificadores e comparadores foram construídos com inversores CMOS, pois um destes inversores, alimentado com uma tensão de 1,1V, pode consumir uma corrente CC tão baixa quanto 400nA, dependendo das dimensões, e proporcionar alto ganho de tensão quando polarizado em sua região linear de operação. Por estes motivos, podem substituir com vantagem amplificadores operacionais e comparadores em algumas aplicações. Um protótipo deste circuito foi implementado com tecnologia CMOS 0,35µm e alcançou um rendimento de 90% / Abstract: This thesis presents the design of a firstorder S-? audioband power amplifier optimized for hearing aid (HA) amplification. The majority of HAs use a 1.1V battery and require very low current consumption to improve battery life. This work made use of amplifiers and comparators based on CMOS inverters because such an inverter, with a 1.1V battery, can operate on a current as low as 400nA, depending on its dimensions, and provide high voltage gain when biased in their linear region. For these reasons, they can substitute with advantage operational amplifiers in some applications. A prototype of this circuit was implemented in a monolithic chip using 0.35µm CMOS technology and achieved 90% of power efficiency / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Une nouvelle chaîne de traction dédiée à un véhicule hybride électrique de poids lourds a été développée dans ces travaux de recherche. A ce stade, la conception et l'optimisation des composants électriques de la chaîne de traction ont été étudiées, notamment les machines synchrones à aimants permanents et les onduleurs de tension associés, ainsi que le train Ravigneaux. En ce qui concerne la conception, un modèle analytique a été créé et qui permet de répondre au cahier des charges simultanément. Les différentes contraintes multiphysiques ont été prises en compte dans le modèle analytique. Ensuite, un modèle numérique via la méthode élément fini a été mise en œuvre. Le modèle numérique nous a permis de valider les performances de la machine électrique. En ce qui concerne l'optimisation, une stratégie de l'optimisation globale a été étudiée. Un exemple d'optimisation a été basé sur un système composé par deux machines électriques et deux onduleurs associés, ainsi que le train Ravigneaux. La comparaison basée sur cet exemple pour l'optimisation locale et globale nous a permis de valider l'avantage de la stratégie de l'optimisation globale. L'expérimentation a été réalisée sur un banc d'essais qui est constitué par la machine prototype et la machine de charge, les deux machines électriques ont été alimentées et pilotées par deux variateurs de fréquence. Les résultats expérimentaux nous ont permis de valider les modèles théoriques. / A new powertrain for a hybrid electric vehicle of heavy duty was developed in this research work. In this case, the design and the optimization of electrical components of powertrain have been investigated involving the permanent magnet synchronous machines, the associated inverters and the Ravigneaux train. Regarding the design, an analytical model was created and that permits simultaneously answering to specification. The various multiphysic constraints have been taken into account in analytical model. And then the numerical model was carried out via finite element method has been implemented. The numerical model allowed us to valid electrical machine performances. Regarding the optimization, a global optimization strategy was investigated. An optimization example was based on a system which was composed of two electrical machines, two associated inverters and the Ravigneaux train; The comparison based on this example between the local optimization and the global optimization, which allowed us to valid the advantage of global optimization strategy. The experimentation has been performed with a test bench involving the prototype machine and the load machine, the two electrical machines were fed and controlled by two frequency drives. The experimental results permit to valid the theoretical models.

Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη και κατασκευή ενός μετατροπέα για την οδήγηση ενός μονοφασικού επαγωγικού κινητήρα. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών. Σκοπός είναι η μελέτη και κατασκευή ενός τριφασικού αντιστροφέα τάσης για τη λειτουργία και τον έλεγχο των στροφών ενός μονοφασικού επαγωγικού κινητήρα. Αρχικά μελετάται η βασική αρχή λειτουργίας του μονοφασικού επαγωγικού κινητήρα και αναλύονται οι τεχνικές εκκίνησης που χρησιμοποιούνται για σύνδεση του κινητήρα απευθείας στο δίκτυο. Ακόμα παρουσιάζονται τα ισοδύναμα κυκλώματα λειτουργίας του μονοφασικού επαγωγικού κινητήρα, η εξίσωση της ηλεκτρομαγνητικής ροπής του και προσομοιώνεται η λειτουργία του για τη μελέτη της στατικής συμπεριφοράς του. Στη συνέχεια γίνεται μια θεωρητική ανάλυση του κυκλώματος του τριφασικού αντιστροφέα τάσης που κατασκευάστηκε, καθώς και όλων των υπόλοιπων κυκλωμάτων που είναι αναγκαία για τη λειτουργία του. Επιπροσθέτως αναλύεται η μέθοδος παλμοδότησης των διακοπτικών στοιχείων του αντιστροφέα τάσης, που είναι η "Ημιτονοειδής Διαμόρφωση του Εύρους των Παλμών" (SPWM). Στο επόμενο βήμα αναλύονται τα τεχνικά χαρακτηριστικά όλων των κυκλωμάτων που κατασκευάστηκαν, και περιγράφεται ο κώδικας του προγράμματος του μικροελεγκτή, που χρησιμοποιήθηκε για την παραγωγή των παλμών. Τέλος, παραθέτουμε παλμογραφήματα και μετρήσεις που προέκυψαν από τα πειράματα που διενεργήθηκαν μετά την ολοκλήρωση της κατασκευής. / This diploma thesis discourse the analysis and construction of a converter topology for single phase induction motor drives. The project was based in the Laboratory of Electromechanical Energy Conversion of the department of Electrical and Computer Engineering of School Engineering of University of Patras. The objective of this project is the analysis and construction of a three phase voltage inverter to control the speed of a single phase induction motor. The first stage of this work is the study of the basic principle of operation of the single phase induction motor and the analysis of the starting techniques, used for the direct connection to the power grid. The equivalent circuits of the running single phase induction motor and the equation of the electromagnetic torque are also presented in this project. Following, there is a theoretical analysis of the three phase voltage inverter circuit, as well of all the remaining circuit, necessary for its function. Moreover the method of pulse generation for the switching elements of the voltage inverter is analyzed, which is the “Sinusoidal Pulse Width Modulation”. The next step is the analysis of the technical characteristics all of the circuits developed, as well the description of the program code for the microcontroller, used to produce the pulses. Finally oscillograph figures and measurements, occurred from the experiments transacted after the finalization of the construction, are adduced.

Submitted by Morgana Silva (morgana_linhares@yahoo.com.br) on 2016-07-26T18:10:50Z No. of bitstreams: 1 arquivototal.pdf: 2752063 bytes, checksum: 886fc73f7f66099f1e033937798f6b7e (MD5) / Made available in DSpace on 2016-07-26T18:10:50Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2752063 bytes, checksum: 886fc73f7f66099f1e033937798f6b7e (MD5) Previous issue date: 2016-02-29 / This paper presents a block diagram modeling of a grid-independent photovoltaic power generation system, including the steps of DC regulation, voltage inversion, and control system based on dynamic simulations in Simulink / Matlab® exclusively using the built-in blocks available in its library. A well-known technique in literature called MPPT (maximum power point tracking) was used for tracking the maximum power of the photovoltaic generation. However, the control that was used to maintain a constant output voltage of the Push-Pull is based on a method that is similar to the MPPT, which configures a novelty of this research. The integration of modeling the entire PV system with these control systems is carried out in Simulink for investigaton and production of simulation results. An experimental platform that includes an emulator of photovoltaic panels, a 1 kW Push-Pull converter, a three-phase inverter with three arms and a hydraulic load constituided by a motor-pump was built in the laboratory. The experimental results corroborate the methodology that was used. / Este trabalho apresenta uma modelagem em diagramação de blocos de um sistema de geração de energia fotovoltaico isolado, incluindo as etapas de regulação CC, inversão de tensão e sistema de controle com base em simulações dinâmicas no ambiente Simulink/Matlab® utilizando, exclusivamente, os blocos built-in disponíveis em sua biblioteca. Uma técnica bem conhecida na literatura foi utilizada para o rastreio da máxima potência da geração fotovoltaica. No entanto, o controle utilizado para manter a tensão de saída constante do Push-Pull é baseado num método similar ao do rastreio da máxima potência, o que configura uma novidade deste trabalho. A integração da modelagem de todo o sistema fotovoltaico com estes sistemas de controle é realizada no ambiente Simulink para averiguação e produção dos resultados de simulação. Uma plataforma experimental que inclui um emulador de painéis fotovoltaicos, um Push-Pull de 1 kW de potência, um inversor trifásico de três braços e uma carga hidráulica constituída por um motobomba foi construída em laboratório. Os resultados experimentais corroboram a metodologia utilizada.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-05T18:23:07Z No. of bitstreams: 1 yuricalillouresdeoliveira.pdf: 2613361 bytes, checksum: b14d216c9e91ffe085e35724d58bc704 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-06-07T15:42:11Z (GMT) No. of bitstreams: 1 yuricalillouresdeoliveira.pdf: 2613361 bytes, checksum: b14d216c9e91ffe085e35724d58bc704 (MD5) / Made available in DSpace on 2016-06-07T15:42:11Z (GMT). No. of bitstreams: 1 yuricalillouresdeoliveira.pdf: 2613361 bytes, checksum: b14d216c9e91ffe085e35724d58bc704 (MD5) Previous issue date: 2016-01-12 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Esta dissertação apresenta um estudo de estratégias de alimentação de cargas hospitalares críticas utilizando conversores estáticos de energia. As cargas hospitalares escolhidas foram os equipamentos de raio x, tomografia computadorizada e ressonância magnética, sendo comparadas as seguintes formas de integração à rede: (i) estrutura com um retificador trifásico conectado à rede e três inversores monofásicos conectados às cargas ou (ii) estrutura com três retificadores monofásicos conectados à rede e três inversores monofásicos conectados às cargas. Por questões de patente, houve dificuldade em se encontrar os circuitos de front-end das fontes de alimentação das cargas hospitalares. Logo, as mesmas foram construídas dentro do ambiente de simulação do software PSIM utilizando dados de medição obtidos na literatura. O controle dos retificadores trifásico e monofásico foi realizados utilizando duas malhas de controle em cascata, com a malha interna controlando a corrente consumida da rede e a malha externa regulando a tensão no barramento CC. Para os três inversores monofásicos de saída foram implementados os controles PI RES e PI SRF visando uma comparação quanto ao desempenho. Como forma de validar o modelo matemático do sistema e o algoritmo de controle, foram feitas simulações utilizando o software PSIM. A análise feita comprovou que os resultados de simulação se mostraram coerentes com a modelagem matemática do sistema. / This master thesis presents a study about feeding strategies of critical hospital loads through power static converters. The chosen hospital loads were the x ray equipment, the computed tomography and the magnetic resonance. The following forms of grid integration were compared: (i) structure with a three-phase rectifier connected to the network and three single-phase inverters connected to the loads or (ii) structure with three single-phase rectifiers connected to the network and three single-phase inverters connected to the loads. Due to patent issues, it was difficult to find the front-end circuits for power supplies of hospital loads. Therefore, the loads were implemented in PSIM software environment using measurement data obtained from literature. The control of three-phase and single-phase rectifiers was implemented using two cascaded control loops, with the inner loop controlling the current drawn from the network and the outer loop regulating the DC bus voltage. For the single-phase inverter, PI RES and PI SRF controls were implemented, targeting a comparison in terms of performance. In order to validate the mathematical model of the system and the control algorithm, simulations were performed using the PSIM software. The analysis showed that the simulation results were consistent with the mathematical modeling of the system.