Šis elektros inžinerijos bakalauro darbas yra aktualus, nes yra kuriami nauji laboratorinių darbu stendai galios elektronikos, kurių dar katedra neturėjo. Taip kuriant naujus mokomuosius stendus bus galima padidinti studijų kokybę, nes bus lengviau paaiškinti vykstančius sudėtingus procesus, kurie yra reikalingi gauti reikiamą valdymo dėsnį. Iki šiol panašūs laboratoriniai darbai buvo atlikinėjami programinėmis įrangomis imituojant elektrines grandines, tačiau toks mokymo būdas yra suidealizuotas, todėl nelabai atitinka tikrovę. Buvo nutarta pagaminti du stendus, susijusius su galios elektronikos disciplinos studijomis. Tai būtų tiristorinio lyginimo tiltelio stendas ir inverterio stendas. Pradinėje gamybos stadijoje programine įranga „MULTISIM“ buvo modeliuojamos stendų atitinkamos elektrinės grandinės ir žiūrima ar rezultatai tenkina norimus gauti parametrus. Toliau sumodeliavus atitinkamas elektrines grandines, buvo braižomos elektrinės schemos, pagal kurias buvo gaminami realūs laboratoriniai stendai. Toliau pagaminti stendai buvo išbandomi ir jų rezultatai palyginami su žinomomis teorinėmis reikšmėmis. Darbo metu buvo pagaminti minėti du stendai. Buvo išbandyta ar jie tinkamai veikia tikrinant oscilografu atitinkamų dalių elektrinės grandinės taškų signalus. Taip pat buvo sukurti stendų aprašai, pagal kuriuos studentai galios elektronikos laboratoriniuose darbuose susipažins su šių stendų įranga bei naudojimosi algoritmu. Be to buvo sukurtos laboratorinių darbų užduotis... [toliau žr. visą tekstą] / The Bachelor’s work in Electrical Engineering is relevant, whereas new power electronics equipment for laboratory works were developed. So far, the department did not have such kind of equipment. Thus, developing the new, it will be possible to improve the study quality, whereas is will be easier to explain the operation of complicated processes. Herewith, similar virtual experimentation was performed using electrical circuit simulation software. However such method of teaching was idealised, therefore it did not meet the reality very much. It was intended to develop two different laboratory equipment sets in relation with the requirements of the Power Electronics course. These include SCR control and voltage inverter modules. In the initial stage, the respective electrical circuits were simulated using “MULTISIM”. Further, the real electrical circuits were designed, made and tested. The simulation and real systems analysis results were in good agreement. The descriptions of the equipment were prepared, which can be used for the laboratory practice. The students will have to perform respective tasks and measurements and familiarise themselves with the principles of power electronic circuit operation. Conclusions: The equipment testing results were in conformity with the theory, therefore they are operating appropriately. Students will be able to obtain appropriate knowledge concerning power electronics devices in the real environment. The price of production of the... [to full text]

Power inverters, used to convert DC power to AC, are often used in e.g. solar power applications. However, they tend to be impractically large and expensive; as such, power miniaturization is an active research area. In this thesis, several classes of modern power inverters are evaluated and compared with regards to size, efficiency and output quality in order to identify areas of potential improvement. Methods for estimation of THD, power losses and input ripple are created and verified against a simulation of a five-level neutral-point-clamped inverter with SPWM control. Finally, this design is implemented physically and is found to achieve 94.5% efficiency and 7% THD under low voltage laboratory conditions, while remaining smaller than an average textbook.

Η εργασία αυτή εχεις ως αντικείμενο την μελέτη και την κατασκευή ενός μετατροπέα συντονισμού για την οδήγηση ενός πιεζοηλεκτρικού κινητήρα οδεύοντος κύματος τύπου Ultrasonic. Αρχικά γίνεται μια θεωρητική αναφορά στους πιεζοηλεκτικούς κινητήρες και τους ηλεκτρονικούς μετατροπείς ισχύος ενώ ακολουθεί η προσομοίωση του μετατροπέα στο Pspice. Ακολούθως αναλύεται η διαδικασία της κατασκευής και ακολουθούν τα πειραματικά αποτελέσματα καθώς και τα συμπεράσματα που λάβαμε. / In this thesis someone can find about designing and manufacturing a resonant inverter in order to control a piezoelectric traveling wave ultrasonic motor. In the first chapters someone can read about the piezoelectric phenomenon, piezoelectric motors and about electronic converters which control the velocity of motors. Next there is a presentation of the Pspice simulation model and results. Furthermore there is the manufacturing procedure of the inverter and at the end there are the results and conclusion of the thesis.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This Master Thesis presents a study considering multilevel inverters formed from two and three level cascaded inverters. The literature presents several papers on asymmetric multilevel inverters and most studies are related to control and/or modulation techniques considering a binary or trinary topology. Also, there are studies that consider a small variation of the inverters input voltage and analyses the system behavior. However, any of these studies performs analysis to obtain the best relation between input voltage of the multilevel system, while this together with switching angles are capable of generating an output voltage with minimum THD. This Master Thesis was developed aiming to get this voltage relation for multilevel systems formed by two and three level inverters. Furthermore, it seeks to find a pattern for the voltage ratio for several cascaded inverters. To obtain the desired results, techniques of selective harmonic elimination was applied to reduce low order harmonics, reducing the need for output filter. To reduce the computational efforts for obtaining the switching angles, the author used considerations of genetic algorithms. This is necessary due to the significant increase of the variables to be determined as the number of cascaded inverters increase. / Esta dissertação de mestrado apresenta um estudo considerando inversores multiníveis formados a partir de inversores dois e três níveis conectados em cascata. Na literatura são apresentados vários trabalhos envolvendo inversores multiníveis assimétricos. As pesquisas, na sua maioria, tratam sobre técnicas de modulação considerando uma topologia binária ou trinaria. Ainda, são apresentadas pesquisas que consideram uma pequena variação nas tensões de entrada dos inversores e analisam o comportamento do sistema. Contudo, ainda não existe um estudo que realize uma análise para obtenção da melhor relação entre as tensões de entrada do sistema multinível. Sendo que estas relações de tensão, juntamente com os ângulos de comutação, são capazes de gerar uma tensão de saída com uma THD mínima. Esta dissertação foi realizada buscando obter esta relação de tensões para sistemas multiníveis formados a partir de inversores dois e três níveis. Além disso, é realizada a busca de um padrão para esta relação de tensão para n inversores conectados em cascata. Para a obtenção dos resultados desejados foram aplicadas técnicas de eliminação seletiva de harmônicos. Com esta técnica, as harmônicas de baixa ordem são eliminadas, reduzindo a necessidade do filtro de saída. Além disso, considerações sobre algoritmos genéticos são realizadas. Este algoritmo é utilizado para reduzir o esforço computacional para a obtenção dos ângulos de comutação. Isto é necessário devido ao aumento significativo das variáveis a serem determinadas à medida que se eleva o número de inversores conectados em cascata.

Les composants semi-conducteurs à base de matériaux à grand gap (SiC et GaN) présentent des caractéristiques intéressantes pour la réalisation de convertisseurs d’électronique de puissance toujours plus intégrés. Cependant, le packaging des composants traditionnels en silicium ne semble plus adapté pour ces nouveaux composants et apparaît même comme un facteur limitant. Le développement d’un packaging adapté aux caractéristiques des composants à grand gap est alors nécessaire. Les travaux développés dans cette thèse proposent un nouveau packaging tridimensionnel basé sur un procédé de fabrication de circuit imprimé. L’architecture du module est basé sur le concept « Power Chip On Chip » dont le principe de base permet de réduire les perturbations électromagnétiques. Le procédé de fabrication des circuits imprimés offre une grande flexibilité pour le routage en trois dimensions et permet de s’affranchir de l’interconnexion par fil de bonding entre le package et la puce. La démarche de conception du module s’appuie sur une approche multi-physique afin de qualifier le comportement électromagnétique et thermique du module puis de proposer des voies d’optimisation. Un prototype d’un module implémentant quatre cellules de commutation en parallèle, à base de MOSFET SiC, a été produit avec des moyens de production industriels. Les différents tests réalisés valident l’approche retenue dans ce projet mais soulignent également les aspects technologiques à approfondir pour la réalisation d’un module de puissance industriel. / Wide-band-gap (WBG) semiconductors (SiC and Gan) offer interesting characteristics to realize high density power electronics converters. Conventional packaging used for silicon devices is no more adapted for those now components. Development of dedicated packaging for WBG devices is absolutely required. This PhD thesis presents a new 3D package based on Printed Circuit Board (PCB) industrial process. The module architecture is based on “Power Chip On Chip” concept which allows reducing electromagnetic perturbations. PCB fabrication process offers high design flexibility in three dimensions and allows removing wire bonding to interconnect power die and package. The power module design process is buit on multi-physics design tools in the aim to quantify electromagnetic and thermal behavior of the module. Furthermore, several optimization parameters are highlighted. A power module prototype, with four commutation cells in parallel based on SiC MOSFET, has been produced thanks to industrial facilities. Tests realized on new power module confirm the validity of the concept but furthermore to highlight critical technological parameters to realize an industrial power module.

abstract: The high penetration of photovoltaic (PV) both at the utility and at the distribu-tion levels, has raised concerns about the reliability of grid-tied inverters of PV power systems. Inverters are generally considered as the weak link in PV power systems. The lack of a dedicated qualification/reliability standard for PV inverters is a main barrier in realizing higher level of confidence in reliability. Development of a well-accepted design qualification standard specifically for PV inverters will help pave the way for significant improvement in reliability and performance of inverters across the entire industry. The existing standards for PV inverters such as UL 1741 and IEC 62109-1 primarily focus on safety. IEC 62093 discusses inverter qualification but it includes all the balance of sys-tem components and therefore not specific to PV inverters. There are other general stan-dards for distributed generators including the IEEE1547 series of standards which cover major concerns like utility integration but they are not dedicated to PV inverters and are not written from a design qualification point of view. In this thesis, some of the potential requirements for a design qualification standard for PV inverters are addressed. The IEC 62093 is considered as a guideline and the possible inclusions in the framework for a dedicated design qualification standard of PV inverter are discussed. The missing links in existing PV inverter related standards are identified by performing gap analysis. Dif-ferent requirements of small residential inverters compared to large utility-scale systems, and the emerging requirements on grid support features are also considered. Electric stress test is found to be the key missing link and one of the electric stress tests, the surge withstand test is studied in detail. The use of the existing standards for surge withstand test of residential scale PV inverters is investigated and a method to suitably adopt these standards is proposed. The proposed method is studied analytically and verified using simulation. A design criterion for choosing the switch ratings of the inverter that can per-form reliably under the surge environment is derived. / Dissertation/Thesis / M.S. Electrical Engineering 2011

Orientador: João Luis Zocoler / Banca: Antônio de Pádua Sousa / Banca: João Carlos Cury Saad / Banca: Marcio Furlan Maggi / Banca: Maritane Prior / Resumo: Um sistema de irrigação deve possibilitar o manejo eficiente da lâmina de água aplicada. Para tal, é necessário avaliar o desempenho do sistema em operação. Este trabalho teve por objetivo avaliar a uniformidade de distribuição e lâmina de água aplicada por um equipamento de irrigação do tipo pivô central em função da variação da velocidade de rotação no conjunto motobomba com o uso de um inversor de freqüência e o efeito da posição da linha lateral nesses parâmetros. O trabalho foi realizado na Fazenda Nossa Senhora Aparecida, no município de Coronel Macedo - SP. Foram testadas duas condições de operação: Ensaio 1 com pressão constante na saída do conjunto motobomba e Ensaio 2 com rotação variável de acordo com a necessidade de altura manométrica. Para cada condição de operação foram testadas três posições de linhas coletoras de água: aclive de 3,45%, nível e declive de 11,78%. O delineamento experimental foi inteiramente casualizado, sendo feitas três repetições em cada posição testada. Aplicou-se a análise de variância seguida do teste de Tukey. O valores médios do coeficiente de uniformidade de Heermann & Hein foi 90,02% e 88,85% para os Ensaios 1 e 2, respectivamente, qualificando a uniformidade de acordo com a Norma da ABNT como muito boa e boa. Também, a posição da linha lateral influenciou 2 significativamente na rotação do conjunto motobomba e conseqüentemente no consumo de energia. A lâmina média ponderada de irrigação aplicada foi 5,84 mm e 5,71 mm para os Ensaios 1 e 2, respectivamente, variando dentro de cada ensaio significativamente (5%) entre as posições de declive versus aclive e nível. Concluiu-se que para os Ensaios 1 e 2 a rotação e a posição da linha lateral influenciaram significativamente na uniformidade de distribuição, lâmina de água aplicada e consumo de energia, exceto para o Ensaio... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: An irrigation system should enable the efficient management of the water depth applied. Therefore, it is necessary to evaluate the performance of the system in operation. This study aimed to evaluate the uniformity distribution and water depth applied in center pivot irrigation systems according to the change in speed of rotation of set motor pump with a frequency inverter and the effect of the position of the lateral line in these parameters. The study was conducted at the Nossa Senhora Aparecida Farm, in the city of Coronel Macedo - SP. Two operation conditions were tested: Test 1 with constant pressure in the output of set motor pump and Test 2 with variable rotation in accordance with the need of the pressure of system. For each condition of operation were tested three positions of lines of collecting: incline of 3.45%, level and the slope of 11.78%. The experimental design was completely randomized, and three repetitions at each position of lines collecting tested. It was applied to analysis of variance followed by Tukey test. The average value of the coefficient of uniformity of Heermann & Hein was 90.02% and 88.85% for Tests 1 and 2, respectively, discribing the uniformity according to the Standard ABNT as very good and good. Also, the position of the lateral line significantly influenced the rotation of set motor pump and consequently in energy consumption. The mean weighed depth of irrigation applied was 5.84 mm and 5.71 mm for Tests 1 and 2, respectively, varying in each test significantly (5%) between positions of the slope versus incline and level. It was concluded that for the Tests 1 and 2, the rotation and the position of and lateral line influenced significantly... (Complete abstract click electronic access below) / Doutor

[pt] Neste trabalho descreve-se as partes de potência e de controle de um inversor trifásico existente na PUC / RJ e o estudo, em pormenor, do sistema de controle com microcomputador. A seguir, são descritas as interfaces entre o micro e o inversor e faz-se a modelação do sistema para o controle. Baseado nesta modelagem é feito o programa de um controlador proporcional-integral (PI) e o estudo de estabilidade do sistema. Os testes das interfaces projetadas e do controle PI acionando o inversor são apresentados e discutidos. Finalmente, são apresentadas as conclusões do trabalho desenvolvido. / [en] This work begins with a description of the power and the control section of a three-phase inverter, and a discussion of the control system with microcomputer. The microcomputer-inverter interfaces are described and a model for the system is developed. Based on this model, a proportional-integral (PI) controller algorithm is presented and the system stability is studied. The results of testes on the interfaces and the complete system are discussed, and the conclusions of this work are presented.

Made available in DSpace on 2014-06-11T19:32:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-01-23Bitstream added on 2014-06-13T19:03:16Z : No. of bitstreams: 1 lima_as_dr_botfca.pdf: 2285385 bytes, checksum: 2981c4b472020de7602b8217b232d18a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Um sistema de irrigação deve possibilitar o manejo eficiente da lâmina de água aplicada. Para tal, é necessário avaliar o desempenho do sistema em operação. Este trabalho teve por objetivo avaliar a uniformidade de distribuição e lâmina de água aplicada por um equipamento de irrigação do tipo pivô central em função da variação da velocidade de rotação no conjunto motobomba com o uso de um inversor de freqüência e o efeito da posição da linha lateral nesses parâmetros. O trabalho foi realizado na Fazenda Nossa Senhora Aparecida, no município de Coronel Macedo – SP. Foram testadas duas condições de operação: Ensaio 1 com pressão constante na saída do conjunto motobomba e Ensaio 2 com rotação variável de acordo com a necessidade de altura manométrica. Para cada condição de operação foram testadas três posições de linhas coletoras de água: aclive de 3,45%, nível e declive de 11,78%. O delineamento experimental foi inteiramente casualizado, sendo feitas três repetições em cada posição testada. Aplicou-se a análise de variância seguida do teste de Tukey. O valores médios do coeficiente de uniformidade de Heermann & Hein foi 90,02% e 88,85% para os Ensaios 1 e 2, respectivamente, qualificando a uniformidade de acordo com a Norma da ABNT como muito boa e boa. Também, a posição da linha lateral influenciou 2 significativamente na rotação do conjunto motobomba e conseqüentemente no consumo de energia. A lâmina média ponderada de irrigação aplicada foi 5,84 mm e 5,71 mm para os Ensaios 1 e 2, respectivamente, variando dentro de cada ensaio significativamente (5%) entre as posições de declive versus aclive e nível. Concluiu-se que para os Ensaios 1 e 2 a rotação e a posição da linha lateral influenciaram significativamente na uniformidade de distribuição, lâmina de água aplicada e consumo de energia, exceto para o Ensaio... / An irrigation system should enable the efficient management of the water depth applied. Therefore, it is necessary to evaluate the performance of the system in operation. This study aimed to evaluate the uniformity distribution and water depth applied in center pivot irrigation systems according to the change in speed of rotation of set motor pump with a frequency inverter and the effect of the position of the lateral line in these parameters. The study was conducted at the Nossa Senhora Aparecida Farm, in the city of Coronel Macedo – SP. Two operation conditions were tested: Test 1 with constant pressure in the output of set motor pump and Test 2 with variable rotation in accordance with the need of the pressure of system. For each condition of operation were tested three positions of lines of collecting: incline of 3.45%, level and the slope of 11.78%. The experimental design was completely randomized, and three repetitions at each position of lines collecting tested. It was applied to analysis of variance followed by Tukey test. The average value of the coefficient of uniformity of Heermann & Hein was 90.02% and 88.85% for Tests 1 and 2, respectively, discribing the uniformity according to the Standard ABNT as very good and good. Also, the position of the lateral line significantly influenced the rotation of set motor pump and consequently in energy consumption. The mean weighed depth of irrigation applied was 5.84 mm and 5.71 mm for Tests 1 and 2, respectively, varying in each test significantly (5%) between positions of the slope versus incline and level. It was concluded that for the Tests 1 and 2, the rotation and the position of and lateral line influenced significantly... (Complete abstract click electronic access below)

abstract: This thesis addresses the design and control of three phase inverters. Such inverters are used to produce three-phase sinusoidal voltages and currents from a DC source. They are critical for injecting power from renewable energy sources into the grid. This is especially true since many of these sources of energy are DC sources (e.g. solar photovoltaic) or need to be stored in DC batteries because they are intermittent (e.g. wind and solar). Two classes of inverters are examined in this thesis. A control-centric design procedure is presented for each class. The first class of inverters is simple in that they consist of three decoupled subsystems. Such inverters are characterized by no mutual inductance between the three phases. As such, no multivariable coupling is present and decentralized single-input single-output (SISO) control theory suffices to generate acceptable control designs. For this class of inverters several families of controllers are addressed in order to examine command following as well as input disturbance and noise attenuation specifications. The goal here is to illuminate fundamental tradeoffs. Such tradeoffs include an improvement in the in-band command following and output disturbance attenuation versus a deterioration in out-of-band noise attenuation. A fundamental deficiency associated with such inverters is their large size. This can be remedied by designing a smaller core. This naturally leads to the second class of inverters considered in this work. These inverters are characterized by significant mutual inductances and multivariable coupling. As such, SISO control theory is generally not adequate and multiple-input multiple-output (MIMO) theory becomes essential for controlling these inverters. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015