Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This Master Thesis presents a new analysis, modeling and design guideline for an Insulated Power Factor Corrected Single-Stage Converter. First, the operating principle is presented which provides a better understanding of the converter. So, based on this new analysis, the two operation modes description and the new steady-state gain of the converter are provided. A new control strategy for the input current control-loop is also proposed which provides an improvement of the total harmonic distortion (THD). The conditions to reset the magnetic flux for the high frequency transformer (HFT) into a switching period and the mitigation of the reactive energy are provided. At the sequence, the transfer functions that describe the dynamic behavior of the output voltage and the input current due to perturbations on duty-cycle and input voltage are derived. These dynamic models are derived based on the averaged equivalent circuit (AEC) obtained by modeling an equivalent DC-DC converter. Finally, the design guideline and experimental results for validation of the mathematical analysis and numerical simulation confirmation are provided. / Esta Dissertação de Mestrado apresenta uma nova análise, modelagem e metodologia de projeto de um conversor CA-CC isolado com um único estágio e correção do fator de potência. Inicialmente, é apresentado o princípio de operação do conversor em estudo propiciando um melhor entendimento do funcionamento do mesmo. Assim, baseada na nova análise, são apresentados os dois modos de operação do conversor e o novo ganho estático resultante. Também é proposta uma nova estratégia de controle para a corrente de entrada do conversor proporcionando uma redução na distorção harmônica total (DHT). Também serão estabelecidas as condições necessárias para a desmagnetização do núcleo do transformador de alta freqüência (TAF) em um período de chaveamento e a minimização de reativos circulantes. Posteriormente, são obtidas as funções de transferências que descrevem o comportamento dinâmico da tensão de saída e da corrente de entrada para perturbações na variável de controle ou na tensão de entrada. Esses modelos dinâmicos serão derivados do circuito médio equivalente (CME) obtido através da modelagem do conversor em estudo operando como um conversor CC-CC equivalente. Por fim, são apresentadas uma metodologia de projeto e os resultados experimentais para a validação da análise matemática e confirmação dos resultados obtidos através de simulações numéricas.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aims to develop a family of electronic converters with electrical isolation to supply a group of power light emitting diodes, applied to street lighting systems. The converters have high power factor and still meets the IEC61000-3-2, for lighting equipment. The integration between the power stages is realized to decrease the number of active semiconductors in the topologies. The topologies are modeled, considering the electrical model of light emitting diodes, and controllers are proposed to turns possible the reduction of the capacitances values in the analyzed topologies. This reduction aims to turns possible the replacement of the electrolytic capacitors for film capacitors, with higher lifetime. The implemented topology is a converter with 70 W of power, supplying 32 power LEDs with 700 mA. The experimental results prove the design methodology, presenting the desired characteristics, like high power factor (0.962), agreement with the standard IEC 61000-3-2 and high efficiency (88%). / Este trabalho visa o desenvolvimento de uma família de conversores eletrônicos com isolação elétrica para o acionamento de um conjunto de diodos emissores de luz de potência, aplicados à iluminação pública. Estes sistemas devem possuir elevado fator de potência e ainda estar de acordo com a norma IEC 61000-3-2, para equipamentos de iluminação. É realizada a integração entre os estágios de potência, de tal forma a reduzir o número de semicondutores ativos das topologias. As topologias são modeladas, considerando o modelo elétrico dos diodos emissores de luz, e é proposto o uso de controladores, visando possibilitar a redução dos valores de capacitâncias das topologias analisadas. Esta redução possibilita a substituição de capacitores eletrolíticos por capacitores de filme, com maior vida útil. Um protótipo para 70 W foi implementado, alimentando 32 LEDs de potência com 700 mA, foram utilizados os conversores Boost-Flyback, Buck-Flyback e Buck-Boost Flyback, além disso o conversor Flyback foi implementado visando a comparação entre conversores integrados e de estágio único. Os resultados experimentais comprovam a metodologia de projeto, apresentando as características desejadas, como elevado fator de potência (0,962), concordância com a norma IEC 6100-3-2 e rendimento de 88%.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This master thesis presents the analysis and design of an electronic drive system for fluorescent induction lamps. This lighting technology, despite being patented since the 60s, is not widely diffused in the market context. However, it is an extremely attractive alternative due to long lifetime and high luminous efficiency. The analysis circuit consists of a power factor correction associated with a power control stage, which provides the lamp ignition and current limitation. An integration methodology is applied in order to reduce the number of active semiconductor switches. The resulting topology, called here SEPIC half-bridge, presents a shared switch able to act, both in the pre-regulator stage, as well as for the power control stage. The number of elements reduction also occurs by magnetic integration. In this case, the pre-regulator inductors are distributed in a single core. For electronic system flexibility, it was inserted the dimming capability, where the low frequency modulation technique was evaluated. This technique is suitable for high power variation rates and provides a stable operation. The topology is controlled by a feedback system ensuring a satisfactory response of the system when subjected to disturbances, in addition to ensuring the correct power to the lamp. The electronic ballast designed behavior was evaluated experimentally. In this situation, there was obtained a low input current distortion associated with a high power factor. The lamp power variation range was 70% (30 W to 100 W), with an average efficiency around 82%. / Neste trabalho de mestrado, apresenta-se a análise e o projeto de um sistema eletrônico de acionamento para lâmpadas fluorescentes de indução. Esta tecnologia de iluminação, apesar de ser patenteada desde a década de 60, ainda é pouco difundida em âmbito comercial. Entretanto, é uma alternativa extremamente atraente devido a longa vida útil e a elevada eficiência luminosa. O circuito analisado consiste de um estágio de pré-regulação do fator de potência associado a um estágio de controle de potência, capaz de prover as necessidades de partida e limitar a corrente aplicada à lâmpada. Para estes estágios, visando a redução do número de semicondutores ativos, é aplicada a metodologia de integração de interruptores. A topologia resultante, chamada de SEPIC half-bridge, apresenta um interruptor compartilhado, capaz de atuar tanto para o pré-regulador, quanto para o controle de potência. A redução do número de elementos se dá também pela integração de magnéticos. Nesta situação, os indutores do pré-regulador são distribuídos em um único núcleo. Buscando a flexibilidade do sistema eletrônico, neste foi inserido a capacidade de variação da intensidade luminosa, onde a técnica de modulação de baixa frequência foi avaliada. Tal técnica é apropriada para elevados índices de variação de potência, além de proporcionar uma operação estável do circuito. A topologia é controlada por um sistema de retroalimentação, capaz de garantir uma resposta satisfatória do sistema quando submetido a distúrbios, além de garantir a potência processada pela lâmpada. O comportamento do reator eletrônico projetado foi avaliado experimentalmente. Nesta situação, obteve-se uma baixa distorção da corrente de entrada e elevado fator de potência. A faixa de variação de potência foi de 70% (100 W à 30 W), com um rendimento médio de 82%.

No description available.

With the increasing demand for fast, cheaper, and efficient power converters come the need for a single-stage power factor correction (PFC) converter. Various single-stage PFC converter proposed in the literature has the drawback of high DC bus voltage at the input side and together with the shift to wide bandgap switches like GaN drives the converter cost higher. However, an interleaved topology with high-frequency isolation was proposed in this research work due to the drastic reduction in the DC bus voltage and extremely low input current ripple thereby making the need for an EMI filter circuit optional.   Meanwhile, this research work focuses on adapting the proposed topology for a high voltage low current application (EV charger - 400V, 7KW) and low voltage high current application (telecom power supply - 58V,  58A) owing to cost benefits. However, all single-stage PFC are faced with the drawback of second-order (100Hz) output harmonic ripple. Therefore, the design and simulation presented a huge peak to peak ripple of about 50V/3A and 26V/26A for the EV charger and telecom power supply case, respectively. This created the need for the design of a ripple cancellation circuit as the research required a peak to peak ripple of 8V and 200mV for the EV - charger and telecom power supply, respectively.   A novel output passive ripple cancellation technique was developed for the EV charger case due to the ease it offers in terms of control, circuit complexity and extremely low THDi when compared with the active cancellation approach. The ripple circuit reduced the 50V ripple to 431mV with the use of a total of 2.2mF capacitance at the output stage.   Despite designing the passive technique, an active ripple cancellation circuit was designed using a buck converter circuit for the telecom power supply. The active approach was chosen because the passive has a slow response and incurs more loss at a high current level. Adding the active ripple cancellation circuit led to a quasi-single stage LLC PFC converter topology. A novel duty-ratio feedforward control was added to synchronize the PFC control of the input side with the buck topology ripple cancellation circuit. The addition of the ripple circuit with the feedforward control offered a peak to peak ripple of 6.7mV and a reduced resonant inductor current by half.   After analysis, an extremely low THDi of 0.47%, PF of 99.99% and a peak efficiency of 97.1% was obtained for the EV charger case. The telecom power supply offered a THDi of 2.3%, PF of 99.96% with a peak efficiency of 95%.

Thesis is devoted to a problem of Power Factor Correction on the low voltage level. It has still its own difficulties despite the fact that topic moved through long development. The main goal of this work is to offer reader variable procedure considering design process. It is based on use of measured data of network analyzer Meg30. The design algorithm has to share a maximum of eventual influencing factors. Therefore the body of master thesis goes through detailed analysis of Power Factor Correction.

La charge d’un véhicule électrique constitue un enjeu stratégique pour les constructeurs automobile et forme un réel défi à relever avant de pouvoir comparer ces véhicules à la simplicité d'usage du véhicule thermique. En effet, l’autonomie limitée, la durée de recharge de la batterie, le coût du déploiement d’une infrastructure de charge rapide, l'impact significatif sur les réseaux électriques et le coût élevé de la batterie sont à l’origine de plusieurs projets de recherche axés sur l’optimisation de la chaîne de recharge du véhicule électrique. Afin d’améliorer l'autonomie d'un véhicule électrique, une solution contraignante mais stratégique consiste à embarquer le chargeur dans le véhicule afin d’assurer la conversion ac-dc de l’énergie à partir des prises de courant. Cette solution permet d’augmenter la disponibilité de la charge pour les utilisateurs. En outre, le chargeur embarqué peut réutiliser tout, ou une partie des éléments déjà existants et nécessaires à la propulsion du véhicule. L'idée étant de pouvoir employer certains éléments de la chaîne de traction électrique, déjà embarqués dans le VE (moteur électrique et onduleur de tension), et d’ajouter un filtre d'entrée et un redresseur afin de concevoir le chargeur. Cette solution permet de réduire le coût du chargeur, sa taille ainsi que le volume nécessaire à l'intégration de ses constituants électriques, on parle alors de chargeur intégré à la chaîne de traction. Cependant, la réutilisation de l’électronique de puissance embarquée engendre des problèmes de compatibilité électromagnétique avec d’autres équipements connectés sur le réseau électrique et aussi avec les dispositifs de protection domestique.Le problème majeur à lever est donc, la limitation des émissions conduites et plus particulièrement des courants de mode commun dans une gamme de fréquence importante. Ce projet de thèse a donc, pour objectif, l’amélioration de la disponibilité de la charge actuelle tout en réduisant le volume du filtre CEM passif. Nous cherchons, à travers ces travaux, à identifier des domaines d'améliorations possibles, à proposer des solutions à bas coûts et à intégrer des modifications au niveau de la commande et de la topologie afin d'optimiser le comportement CEM, tant en basses fréquences (0 - 2 kHz) qu’en hautes fréquences (150 Hz- 30 MHz), de ce chargeur embarqué intégré sans isolation galvanique. Les propositions doivent répondre simultanément aux besoins de recharge domestique en monophasé (à 3.7 kW et à 7.4 kW) et rapide en triphasé (à 22 kW et à 43 kW) sans pour autant augmenter le volume ni les coûts engendrés. Ainsi, cinq axes de travail sont étudiés: l’optimisation du comportement CEM (0-2 kHz) du chargeur en monophasé ; l’optimisation du comportement CEM (0-2 kHz) du chargeur en triphasé ; le développement, la mise en œuvre et l’instrumentation de deux bancs expérimentaux exploités pour l’obtention de résultats; la proposition d’une approche de modélisation CEM de la structure qui tient compte du mode commun et du mode différentiel ; et la proposition de solutions pour la réduction des émissions conduites (150 kHz – 30 MHz). / Battery chargers for electric vehicles are classified as on-board or off-board chargers. Off-board chargers are not constrained by size or weight but introduce additional cost to the infrastructure through the deployment of a high number of charging stations. In order to meet the needs of electric vehicle users in terms of charging availability, on-board chargers that achieve ac/dc conversion are retained. Furthermore, on-board chargers are classified as standalone or integrated systems. By reusing parts of the traction power train for charging, the latter reduces the cost of the charger. Disadvantages of integrated systems include electromagnetic compatibility issues and complex control schemes.This work presents the power quality performance analysis and control optimization of an on-board non-galvanically isolated electric vehicle charger integrated to the traction’s power train. In order to be able to evaluate the high frequency conducted common mode emissions (150 kHz - 30MHz) of a power conversion structure, one needs to develop a good current control scheme that establishes a high-quality low frequency behavior (0 - 2 kHz). Therefore, different aspects related to the power factor correction of the single-phase as well as the three-phase charging configurations are studied: the control scheme for the regulation of the charging power, the displacement power factor correction, the suppression of the grid current harmonics and the active damping of the input filter’s resonance. Two experimental test benches are developed using two different technologies (Silicon IGBTs vs. Silicon Carbide Mosfets). Experimental results are provided.This work also presents a comprehensive approach to modeling the CM and the DM EMI behavior of a power electronics structure. This method is applied to the charger in its single-phase and three-phase configurations. The models allow to evaluate the fluctuating internal nodes and to study the effect of various proposed mitigation solutions on the CM emissions. The models are also developed in the intent of being injected into optimization algorithms for the future design of an optimal EMI filter.

Småskalig vattenkraft är en stor användare av reaktiv effekt då de ofta har asynkrongeneratorer. Det gör att det finns ett reellt behov för faskompensering, dels för att minska distorsion i nätet samt för att förbättra deras ekonomiska ställning, då elbolag ofta tar ut en avgift för överskridande användning av reaktiv effekt. Det ligger också i allmänhetens intresse att ha en god elkvalitet och hålla störningar och avbrott nere, vilket kan erhållas med faskompensering och filtrering av övertoner. Det finns olika tekniker för faskompensering med sina respektive för- och nackdelar som specificeras efter anläggningens krav och förhållanden. Dessa tekniker är ett kondensatorbatteri, passiv och aktiv reglering, övermagnetiserad synkronmaskin, static var compensator (SVC) och static synchronous compensator (STATCOM). Med hjälp av simuleringar och ekonomisk kalkylering har deras egenskaper och investeringspotential analyserats. Det har resulterat i att ett kondensatorbatteri är en ekonomiskt god investering men med nackdelen att det blir en stor transient vid inkoppling. Aktiv reglering bistår med en snabb, kontinuerlig faskompensering men har större driftkostnader och en kortare livslängd. Övermagnetiserad synkronmaskin har en god ekonomisk framtidsutsikt men med en något långsammare reaktionstid. SVC och STATCOM är mer applicerbar på större anläggningar, eller för nät som har en större nytta av dess flexibilitet. / Small scale hydropower is a big user of reactive power, mainly because of their use of asynchrounous generators. Power companies are charging their customers a fee for an extensive use of reactive power. Which gives rise to a need of correction of the power factor as well as reduction of distorsion in the network. It is also in the interest of the general public to acquire a good electric quality in terms of keeping distorsion and interruptions in the network to a minimum. This can be achieved by using different methods for power factor correction and filtration of harmonics. These methods have their own inherent advantages and disadvantages described after the facility’s specific needs and requirements. These methods are a capacitor bank, passive and active regulation, overexcited synchronous machine, static var compensator (SVC) and static synchronous compensator (STATCOM). Simulations and economical calculations have been used to determine these properties. A capacitor bank has been proven to be a good economical investment, but it has high transients during switching conditions. Active regulation also shows a good profitability and provides a fast, continuous regulation of the reactive power, though it has higher operating costs and low life expectancy. The overexcited synchronous generator has a positive outlook in economic terms, with the drawback of a slower response time. SVC and STATCOM are more applicable to larger facilities or weak networks.

No description available.

This master thesis presents the development of a 100 W LED driver, suitable for outdoor and street lighting. In order to match the driver and LED features, special functionalities are added to the electronic system. To obtain a long lifetime, electrolytic capacitor are exchanged by film capacitor, with longer useful lifetime. However, this practice outcome in higher bus voltage ripple, which have to be compensated in the LED current control stage, named as power control stage. To achieve special functionalities, the proposed driver is designed to operate with universal input voltage and dimming capability, being the entire driver control implement in a digital way, increasing significantly the LED driver flexibility. After the literature review, which aimed to evaluate the characteristics of the LED driver topology structure, the two independent stage topology is selected. The buckboost converter operating in discontinuous conduction mode is employed on the power factor correction stage. The power control stage is composed by the DC/DC LLC resonant converter. Once the LED driver topology is defined, each converter is designed, following by the small signal modeling and the control system design. Experimental results of the driver operating with a reduced bus voltage capacitance (25 μF), are presented for a universal input voltage (85 – 265 VRMS) and different dimming levels (100% − 30%). A high power factor (> 0,94) and a medium to high efficiency (> 82%) is noticed in whole operation points, as well as, a reduced flicker (< 10%), being in accordance with the recent released IEEE Std 1789-2015 and IEC61000-3-2 Class C. / Este trabalho apresenta o desenvolvimento de um driver para o acionamento de um módulo de LEDs de 100 W, destinado a iluminação de exteriores ou iluminação pública. De forma a compatibilizar as características do LED com o driver, diferentes funcionalidades e condições de operação são adicionadas ao sistema eletrônico desenvolvido. Para alcançar longa vida útil, o driver desenvolvido substituiu os capacitores eletrolíticos por capacitores de filme. No entanto, essa prática resulta em maiores ondulações da tensão de barramento, as quais são compensadas pelo estágio de controle da corrente dos LEDs. De modo a aumentar as funcionalidades do driver, o mesmo opera com tensão de entrada universal e controle da intensidade luminosa, sendo o sistema de controle do driver implementado de forma digital, aumentando consideravelmente sua flexibilidade. Após revisão da literatura, a qual objetivou avaliar as características das estruturas e topologias empregadas em drivers para LEDs, seleciona-se a estrutura de dois estágios independentes. O conversor buck-boost operando no modo de condução descontínuo de corrente é empregado no estágio de correção do fator de potência. Para o estágio de controle da corrente dos LEDs, utiliza-se o conversor CC/CC meia ponte ressonante LLC. Definida a estrutura topológica, bem como os conversores utilizados, o projeto dos elementos é desenvolvido, seguido da modelagem dinâmica e do projeto do sistema de controle de cada estágio. Resultados experimentais do driver com reduzida capacitância de barramento (25 μF) mostram a sua operação com tensão de entrada universal (85 – 265 VRMS) e controle de intensidade luminosa (100% − 30%). Verificou-se um alto fator de potência (> 0,94) em toda a faixa de operação, rendimento média-alto (> 82%), bem como reduzida modulação de intensidade luminosa (< 10%), estando em conformidade com a IEEE Std 1789-2015 e a IEC61000-3-2 Classe C.