Hysteresis current control has been widely used in power electronics with the advantages of fast dynamic response under parameter, line and load variation and ensured stability. However, a main disadvantage of hysteresis current control is the uncertain and varying switching frequency which makes it difficult to form an average-value model. The changing switching frequency and unspecified switching duty cycle make conventional average-value models based on PWM control difficult to apply directly to converters that are controlled by hysteresis current control. In this work, a new method for average-value modeling of hysteresis current control in boost converters, three-phase inverters, and brushless dc motor drives is proposed. It incorporates a slew-rate limitation on the inductor current that occurs naturally in the circuit during large system transients. This new method is compared with existing methods in terms of simulation run time and rms error. The performance is evaluated based on a variety of scenarios, and the simulation results are compared with the results of detailed models. The simulation results show that the proposed model represents the detailed model well and is faster and more accurate than existing methods. The slew-rate limitation model of hysteresis current control accurately captures the salient detail of converter performance while maintaining the computational efficiency of average-value models. Validations in hardware are also presented.

The primary objective of this thesis is to develop a process for fabricating integrated circuits based on thin-film transistors (TFTs) using zinc tin oxide (ZTO) as the channel layer. ZTO, in contrast to indium- or gallium-based amorphous oxide semiconductors (AOS), is perceived to be a more commercially viable AOS choice due to its low cost and ability to be deposited via DC reactive sputtering. In the absence of an acceptable ZTO wet etch process, a plasma-etching process using Ar/CH₄ is developed for both 1:1 and 2:1 ZTO compositions. An Ar/CH₄ plasma etch process is also designed for indium gallium oxide (IGO), indium gallium zinc oxide (IGZO), and indium tin oxide (ITO). Ar/CH₄ dry etches have excellent selectivity with respect to SiO₂, providing a route for obtaining patterned ZTO channels. A critical asset of ZTO process integration involves removing polymer deposits after ZTO etching without active layer damage. A ZTO process is developed for the fabrication of integrated circuits which use ZTO channel enhancement-mode TFTs. Such ZTO TFTs exhibit incremental and average mobilities of 23 and 18 cm²V⁻¹s⁻¹, respectively, turn-on voltages approximately 0 to 1.5 V and subthreshold swings below 0.5 V/dec when annealed in air at 400 °C for 1 hour. Several types of ZTO TFT circuits are realized for the first time. Despite large parasitic capacitances due to large gate-source and gate-drain overlaps, AC/DC rectifiers are fabricated and found to operate in the MHz range. Thus, they are usable for RFID and other equivalent-speed applications. Finally, a ZTO process for simultaneously fabricating both enhancement-mode and depletion-mode TFTs on a single substrate using a single target and anneal step is developed. This dual-channel process is used to build a high-gain two-transistor enhancement/depletion inverter. At a rail voltage of 10 V, this inverter has a gain of 10.6 V/V, the highest yet reported for an AOS-based inverter. This E/D inverter is an important new functional block which will enable the realization of more complex digital logic circuits. / Graduation date: 2009

<p>U tezi je prikazana analiza pogona sa šestofaznom asimetričnom<br />asinhronom mašinom koja se napaja iz šestofaznog invertora.<br />Predložen je novi način upravljanja šestofaznim invertorom kojim<br />su rešeni nedostaci do sada predloženih tehnika upravljanja a koji<br />se pre svega ispoljavaju kroz dva aspekta: nekontrolisano generisanje<br />dodatnih gubitaka i teška implementacija u komercijalno dostupne<br />digitalne kontrolere. Rezultati svih teorijskih analiza i navoda su<br />dokazani računarskim simulacijama i eksperimentalnim putem.<br />Eksperimentalna verifikacija je ostvarena korištenjem<br />laboratorijskog prototipa koji se temelji na dSPACE kontrolnom<br />sistemu.</p> / <p>Doctoral thesis shows the analysis of the dual three-phase induction machine<br />drive. A novel way of driving of the six-phase inverter is proposed. A<br />proposed method solves disadvantages of currently proposed driving<br />techniques which are manifested in two aspects: the uncontrolled generation<br />of additional losses and difficult implementation in commercially available<br />digital controllers. The results of theoretical analysis and the statements are<br />proven by computer simulation and experimentally. Experimental verification<br />is achieved using a laboratory prototype that is based on dSPACE control<br />system.</p>

Ce mémoire présente le travail de thèse réalisé auprès des laboratoires LAPLACE et SATIE ainsi que les services EDYNE3 et EDYYLIC d'AIRBUS OPERATIONS. Le sujet porte sur les problèmes CEM apparaissant dans les convertisseurs de puissance embarqués à bord des futurs avions plus électriques. Le manuscrit est composé de cinq parties. La première partie, d'introduction, traite de la problématique CEM avion, la deuxième de la modélisation des éléments de la chaine de conversion DC/AC étudiée. Le troisième est composé d'une étude comparative par simulation des différentes solutions. La quatrième partie traite de la réalisation de la solution choisie et enfin le cinquième et dernier chapitre de l'étude expérimentale de celle-ci. / The studies conducted during this thesis deals with conducted EMC problems of an inverter associated to its actuator. Accurate high frequency models of every element of the DC/AC converter and actuator have been realised from measures. Then a comparative study of different topologies of converters have been led from simulations in order to determine the best solution minimising EMC current. The selected inverter was realised and the experimental results were compared to simulations validating them. Finally, a comparison of EMC filters architecture led to choose a better solution in order to avoid the increasing of mass.

La commande sans capteur mécanique de la machine synchrone à aimants permanents est un sujet largement répandu dont les plus grandes difficultés connues, quel que soit l’observateur utilisé, sont celui du démarrage à vitesse nulle et plus largement de la commande aux basses vitesses, et celui du rejet des fortes perturbations du couple. Afin d’y faire obstacle, diverses adaptations des algorithmes d’observateur ont été proposées afin d’améliorer le comportement de la machine en commande sans capteur. Par ailleurs, il est couramment admis que les déchets de tension produit par l’onduleur sont nuisibles à l’observation de la position, les tensions de référence étant légèrement différentes des tensions appliquées aux enroulements de la machine. Quelques propositions apparaissent dans certaines publications notamment en établissant un algorithme de compensation. C’est ainsi que les travaux de cette thèse portent sur cette thématique, celle d’améliorer la commande sans capteur dans les situations d’observabilité difficile en proposant une solution originale afin de faire correspondre au mieux les tensions appliquées à la machine et les tensions de référence utiles à l’observateur. Les résultats montrent que la solution proposée et largement analysée améliore considérablement le comportement de la machine en commande aux basses vitesses et en rejet de perturbation, tant en régime permanent qu’en régime transitoire ; une analyse de Fourier des courants mesurés atteste l’efficacité de la méthode et une analyse des grandeurs observées par la statistique descriptive met en lumière l’intérêt de l’algorithme. Nous montrons ainsi que la solution proposée permet d’observer la vitesse et la position en deçà de la vitesse mécanique de 15 rad/s alors que la commande est instable en deçà de 20 rad/s quand la solution n’est pas mise en œuvre. Un constat similaire apparaît en rejet de perturbation. D’autres résultats montrent que l’observation à plus basse vitesse est entachée d’une perturbation liée à un couple pulsatoire dont l’origine peut être le couple de détente, lequel n’est pas pris en compte par le modèle de la machine. / The sensorless control of the permanent magnet synchronous machine is a subject widely spread. Two great difficulties are known; (i) the start at nil initial speed and more generally the control at very low speed whatever the observer used and (ii) the high torque disturbance rejection. In order to hinder these difficulties numerous modifications of observer algorithms were proposed to improve the performances of the permanent magnet synchronous machine sensorless control. Moreover, we admit commonly that the drop voltages due to the inverter are prejudicial to the position estimated, because the difference between the voltage reference transmitted to the PWM (pulse width modulation) and the motor winding voltage is not negligible at low speed and low load torque. According to the literature, several papers propose some solutions by compensation algorithms and voltage estimator in particular. So, the goal of this thesis is to estimate the winding voltage and to apply the state observer by Extended Kalman Filtering to improve more finely the sensorless control. We propose an original solution to estimate the voltage references which is applied to the observer. Numerous experimental results show the attractive effects in marked contrast to the sensorless control results without estimation of the winding voltages. The results of sensorless control show that the solution proposed which widely analysed improves significantly the estimation errors of the motor running in low speed range and low torque disturbances range. Fourier analyses and statistic data obtained in steady state speed and results during the transient response indicate complementary results and highlight the interest of the estimation algorithm. Our study brings out that the estimation error reduction allows to running the motor at mechanical speed short of 15 rad/s. In the other hand, the system is instable with speed short of 20 rad/s if the voltage references are used by the observer rather than the estimation voltages. The same improvement appears in disturbance rejection. Other results show that the estimated position errors at lower speed increases in spite of the estimation algorithm. In fact, the torque disturbances are dominant at low speed, low load torque and are harmful to control the electromagnetic torque.

Este trabalho, constitui-se em uma contribuição para o estudo das estratégias de mo-dulação direta baseadas em histerese e que funcionam em frequência fixa de comutação. Tem como objetivo principal propor a estratégia delta modificada, que diferencia-se na forma de ajuste da largura de banda de histerese, alterando-se seus limites e em como executa o comando de bloqueio das chaves de potência, para que a corrente de saída se mantenha em frequência fixa de operação e apresente rápida resposta dinâmica no sistema controlado. Para tanto, não necessita da utilização de derivadas, nem de uma corrente média de referência, tão pouco, se utiliza dos tempos de comutação. A estratégia proposta, comprova que é possível produzir os adequados pulsos de comando para o processamento da energia proveniente de célula combustível, através do conversor estático de potência, utilizando-se, principalmente, dos valores de ultrapassagem nos limites estabelecidos de histerese. Como objetivo secundário desta pesquisa, desenvolve-se um conversor CC/CC auxiliar para adaptar e estabilizar a energia proveniente da CAC, compondo-se um sistema útil que serve de base para fornecer energia, aos mais diversos tipos de cargas em CC. Além disso, apresenta-se uma revisão das estratégias de modulação em modo direto para o controle da corrente de saída no conversor estático, tendo como base a tensão nos terminais de um indutor. Contudo, outras estratégias são naturalmente citadas, no transcorrer deste trabalho, devido haver combinações entre as diferentes estratégias moduladoras e controladoras comentadas. / This work, is a contribution to the study of direct modulation strategies based on hysteresis and that operate at fixed switching frequency. Its main objective is to propose the modified delta strategy, which differentiates from the others strategies in the form of adjustment of hysteresis bandwidth, changing its limits and in executing the locking command of the power keys, so that the output current is maintain at fixed frequency of operation and a rapid dynamic response in the controlled system. In order to do so, it does not require the use of derivatives or a reference average current and also the switching times are not used. This strategy shows that it is possible to produce the appropriate command pulses for the processing of fuel cell energy by the static power converter using mainly the exceedance limit values. As a secondary objective of this research, an auxiliary DC/DC converter is developed to adapt and stabilize the energy coming from the fuel cell, forming a useful system that serves as a base to supply power to the most diverse types of DC loads. In addition, we present a review of the direct-mode modulation strategies for the control of the output current in the static converter, updating data, and based on the voltage at the terminals of an inductor; how-ever, others strategies are naturally cited because there are combinations between the different modulating strategies and controllers commented on in the course of this work.

Nos últimos 20 anos, o inversor de frequência PWM passou a ser largamente utilizado. Dentre as razões principais de sua ampla difusão, cita-se a introdução do IGBT que, devido à sua capacidade de comutação rápida, possibilitou a redução de perdas, tamanho e custo dos conversores, ao mesmo tempo em que permitiu o uso do motor de indução em aplicações que demandam alto desempenho dinâmico. Porém, esta mesma característica que trouxe tais benefícios, contribuiu para acentuar os efeitos relacionados a fenômenos eletromagnéticos, devido à rápida transição que produz sinais em alta frequência, responsáveis por tornar os sistemas de acionamentos potenciais fontes de interferência eletromagnética. Os principais fenômenos desta natureza são a tensão de onda refletida, associada a ruídos de modo diferencial, e a corrente de modo comum. De maneira geral, a corrente de modo comum tem maior potencial de contribuição para a emissão radiada que a de modo diferencial e, em sistemas de acionamento, constitui a principal fonte de interferência eletromagnética. Esta não é resultado apenas da rápida comutação dos IGBTs, mas, também, da configuração do sistema, que propicia o surgimento das tensões de modo comum. Este trabalho visa estudar alternativas que minimizem, naturalmente, estas tensões através de sua configuração, reduzindo-se a necessidade de novos componentes, como filtros passivos ou circuitos ativos. Ressalta-se, assim, que o primeiro passo consistiu-se na compreensão do problema de geração da tensão de modo comum. Visando atingir os propósitos anteriormente mencionados, foi idealizado um inversor, composto de duas pontes chaveando em oposição, chamado de duplo-trifásico. A partir de simulações, avaliou-se seu potencial e definiu-se sua implementação, a partir de dois inversores idênticos. Testou-se o protótipo contra um terceiro módulo de mesmo tipo, em iguais condições. A comparação dos resultados indicou que a configuração proposta pode ser eficiente no controle do ruído de modo comum, obtendo-se valores de redução de 86%. Nota-se que o comportamento observado via o protótipo, permite um melhor entendimento dos fenômenos relativos à circulação da corrente de modo comum. Desta forma, à luz da pesquisa realizada, nota-se que, conceitualmente, a solução proposta se destaca das demais apresentadas na literatura pela sua exequibilidade e simplicidade. / Over the last 20 years, the PWM frequency inverter has become widely used. Among the main reasons for its widespread distribution is the introduction of the IGBT, due to its ability for fast switching allowing the reduction of losses, size and cost of the converters, and the use of the induction motor in applications that demand high dynamic performance. However, this same characteristic that brought such benefits, stressed the effects related to electromagnetic phenomena, due to the fast transition that produces high frequency signals, responsible for turning drive systems, potential sources of electromagnetic interference. The main phenomena of this nature are the reflected wave overvoltage, associated with differential mode noise, and the common mode current. In general, the common mode current has greater potential of contribution to the emission of radiated interference than the differential mode current and is the main source of electromagnetic interference in drive systems. The common mode current is not just the result of the fast transitions of IGBTs, but also of the system configuration, which produces common mode voltages. This work aims to study alternatives that minimize, naturally, those voltages through its configuration, reducing the need for additional components, such as passive filters or active circuits. It is pointed, that the first step consisted in the understanding of the problem of the common mode voltage generation. In order to address this objective, an inverter composed of two bridges, switching in opposition, called double-three-phase was designed. Its potential for noise mitigation, as well, its implementation, with two identical inverters was evaluated by simulations. The prototype was tested against a third module of the same type, under the same conditions. The comparison of the results indicated that the proposed configuration can be efficient in the common mode noise control, with 86% reduction. The behavior observed through the prototype allows a better understanding of the phenomena involving common mode current. Thus, in the light of the research, we note that, conceptually, the proposed solution stands out for its practicality and simplicity, from the others presented in the literature.

Depuis les dix dernières années, dans les domaines liés aux transports (automobile, avionique, ferroviaire, naval), les technologies thermiques et hydrauliques tendent à laisser de plus en plus de place aux systèmes électriques. L’intérêt et le dynamisme de la Recherche en électronique de puissance se justifient par le rôle déterminant que la discipline joue au sein du développement des systèmes embarqués "plus électriques". Ce mémoire de thèse s’intéresse à l’étude de convertisseurs d’électronique de puissance, les onduleurs à source impédante, en tant que topologies alternatives aux architectures existantes au sein des systèmes de traction électrique. Plusieurs études sont établies suivant différents critères, qui, au delà d’une simple comparaison avec les architectures conventionnelles, proposent des solutions et des améliorations intervenant aussi bien dans le contrôle du système que dans sa topologie initiale. Ces études sont toutes appliquées à un système de traction électrique muni d’une machine synchrone à aimants et d’un onduleur à source impédante alimentée par une source de tension continue. Les résultats qui en découlent ont montré de larges intérêts de ces topologies concernant la maîtrise de la qualité du courant de batterie (annulation de ses ondulations hautes fréquences) mais aussi la maîtrise de certaines contraintes liées aux vieillissement des machines (possibilité de maîtriser les dv/dt). Certains inconvénients sont néanmoins établis comme le fait que la topologie n’offre guère d’amélioration du rendement (en comparaison avec les structures classiques) ou comme le fait que l’architecture rende dépendantes les commandes de l’onduleur à source impédante (côté DC) et de la machine (côté AC) / Over the past ten years, hydraulic and thermal technologies tend to make room for electrical system. Fields related to transportation (automotive, avionics, railway or naval) are directly impacted. The interest and dynamism in power electronics Research are justified by the impact of such a field in the development of embedded systems. This thesis focuses on the study of impedance-source inverters as possible topologies to replace conventional ones. Several studies are conducted according to different criteria and do not aim at only comparing the topologies. It proposes solutions and improvements in the control system as well as in its basis architecture. These studies are all applied to an electric traction system composed of an synchronous machine fed by an impedance-source inverter. It is showed that large interests come out of the obtained results. For instance, the cancellation of the high-frequency current ripples allows mastering the quality of the battery current. Moreover, some constraints as regards machine ageing can be reduced by mastering the slew rates dv/dt. Some drawbacks are nevertheless pointed out. There is no need in using such a topology to improve efficiency that is above the same as conventional structures. Moreover, controls of DC-side AC-side of the system are dependent due to the fact that inverter’s control is used to step up the DC-bus voltage

Orientador: Carlos Alberto Canesin / Resumo: Considerando o atual crescimento dos sistemas baseados em fontes de energia renováveis para a Geração Distribuída (GD), novas estruturas de potência estão sendo desenvolvidas para os sistemas de conversão. O presente estudo propõe a utilização do Inversor Integrado Cuk para o processamento da energia solar fotovoltaica proveniente de um conjunto de módulos fotovoltaicos. Este inversor é o resultado da integração de um conversor Cuk e um inversor de ponte completa, sendo capaz de realizar as funções de elevação e redução de tensão, e a função de converter a corrente continua em alternada, possuindo um grande potencial para a obtenção de uma estrutura de potência de reduzido volume e alto rendimento, garantindo uma baixa distorção harmônica da corrente injetada à rede. Neste trabalho de dissertação são apresentadas as análises quantitativa e qualitativa do inversor com o objetivo de mostrar em detalhes o seu funcionamento e apresentar as principais equações elétricas dos componentes reativos e semicondutores. Além disso, para a obtenção do modelo dinâmico em pequeno sinal do inversor, o método de média do circuito e modelagem média de interruptores é utilizado a fim de projetar os controladores do modo de controle adotado, o qual consiste em dois laços de corrente retroalimentados. Por outro lado, uma comparação das diferentes configurações de módulos fotovoltaicos conectados ao inversor é realizada através dos dados de simulação, a fim de obter a configuração com as melhores c... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Considering the current growth of the renewable energy sources-based systems for Distributed Generation (DG), new power structures are being developed for the conversion systems. The present study proposes the use of the Cuk Integrated Inverter for the processing of photovoltaic solar energy from a set of photovoltaic modules. This inverter is the result of the integration of a Cuk converter and a Full Bridge inverter, being able to perform the functions of raise and reduce voltage, and the function of converting the direct current (DC) to alternating current (AC), possessing a great potential for obtaining a power structure of reduced volume and high performance, guaranteeing a low harmonic distortion of the current injected into the electric grid. In this research work, the quantitative and qualitative analysis of the inverter are presented in order to show in detail its operation and present the main electrical equations of the reactive and semiconductor components. In addition, to obtain the dynamic model in small signal of the inverter, the method of Circuit Averaging and Averaged Switch Modeling is used in order to design the controllers of the adopted control mode, which consists of two feedback loops of current. On the other hand, a comparison of the different configurations of photovoltaic modules connected to the inverter is performed by simulation data, in order to obtain the configuration with the best performance characteristics of the system. The maximum power p... (Complete abstract click electronic access below) / Mestre

O objetivo principal deste trabalho é o desenvolvimento de controladores robustos baseados no princípio do modelo interno, em referenciais síncrono e estacionário, para aplicação ao estágio de saída de uma fonte ininterrupta de energia (UPS) a fim de minimizar a distorção na tensão de saída causada pela conexão de cargas não lineares balanceadas e desbalanceadas. A formulação em referencial estacionário (abc) é realizada através da aplicação de controladores com múltiplos modos ressonantes, a fim de se estabelecer erro nulo ao seguimento de referência senoidal e rejeição de distúrbios na tensão de saída devido às correntes com elevado conteúdo harmônico drenadas pelas cargas. Além disso, o controle é formulado em referencial síncrono (dq0) utilizando controladores Proporcional-Integral (PI) convencionais muito difundidos na maioria das aplicações comerciais de UPS. O projeto de ambos controladores é realizado utilizando uma metodologia de controle robusto com realimentação de estados, onde os parâmetros dos controladores são determinados através da resolução de um problema de otimização convexa sujeito a um conjunto de restrições na forma de desigualdades matriciais lineares (LMI). Uma análise comparativa de desempenho é realizada entre controladores com um modo ressonante (sintonizado na fundamental) e o PI em dq0, pois apresentam estruturas funcionalmente equivalentes sob a ótica do princípio do modelo interno aplicada a seus respectivos referenciais. Além do mais, demonstra-se a melhoria no desempenho com o uso dos controladores múltiplo ressonantes em referencial estacionário onde escolhe-se as frequências de ressonância de cada modo de maneira a suprimir os efeitos de harmônicas específicas na tensão de saída da UPS. A análise comparativa entre os controladores propostos é realizada através de simulações numéricas, utilizando os procedimentos de ensaio dinâmico e estático e as exigências estabelecidas pela norma internacional IEC 62040-3. / The main objective of this work is the development of robust controllers based on the internalmodel principle, in synchronous and stationary frames, applied to the output stage of an uninterruptible power supply (UPS), in order to minimize the output voltage distortion caused by the connection of balanced and unbalanced nonlinear loads. The formulation in stationary abc-frame is accomplished through the aplication of a multiple resonant controller, so that, it is possible to achieve zero-error tracking of the sinusoidal reference and disturbances rejection on the output voltage due to the high amount of harmonic currents drained by the loads. Moreover, a controller in synchronous reference frame (dq0 axis) is formulated through the application of conventional Proportional-Integral (PI) controllers which are widely used in comercial UPS applications. The design of both controllers is formulated using a state-feedback robust controlmethod, in which the controller parameters are determined by solving a convex optimization problem subject to a set of LMI constraints. A comparative analysis on the performance of the single-mode resonant controller (tuned at the fundamental frequency) and the PI controller is performed, because these controllers are functionally equivalent in the sense of the internal model principle applied to their respective frames. Furthermore, the improvement in performance is demostrated with the use of multiple resonant controllers in stationary abc-frame where the resonance frequencies are chosen to suppress the effects of a specific harmonic in the UPS output voltage. The comparative analysis of the proposed controllers is performed through numerical simulations, making use of the dynamical and steady-state test methods and performance requirements defined by the IEC 62040-3 international stardard.