Projeto otimizado para minimização de perdas em um conversor bidirecional aplicado a sistemas autônomos de iluminação-Tese de doutorado- Autoria:Duarte, Renan Rodrigo-UNIVERSIDADE FEDERAL DE SANTA MARIA-BRASIL

 

RESUMO 

O presente trabalho apresenta o desenvolvimento de um sistema autônomo de iluminação pública baseado em energia solar fotovolaica e diodos emissores de luz (LEDs). O sistema deve ser capaz de carregar um banco de baterias durante o dia através de um arranjo fotovoltaico e suprir uma carga LED durante a noite. Um conversor bidirecional com transistores de nitreto de gálio (GaN) é utilizado de forma a obter uma estrutura com elevado rendimento e, com isso, otimizar o tamanho do banco de baterias e arranjo fotovoltaico para maximizar a autonomia do sistema ou reduzir os custos de produção, dependendo dos objetivos da aplicação. Foi desenvolvida uma metodologia completa e otimizada para o projeto dos elementos deste sistema autônomo de iluminação. Esta metodologia baseia-se em um algoritmo de busca discreta que avalia um conjunto de componentes disponíveis comercialmente para determinar a melhor combinação de componentes e o melhor ponto de operação do circuito, de modo a minimizar as perdas de energia ao longo do período de operação do sistema. Neste documento é apresentada, inicialmente, uma revisão bibliográfica de aspectos teóricos relacionados aos sistemas autônomos de iluminação, como fonte fotovoltaica, baterias, carga LED, topologias de conversores e soluções comerciais disponíveis. Uma revisão sobre interruptores GaN também é apresentada, abrangendo seu histórico, princípio de funcionamento, características e estado da arte da tecnologia em termos de dispositivos comerciais. Para validar experimentalmente a topologia proposta, um protótipo de 100 W com frequência de comutação arbitrária foi desenvolvido e avaliado. No modo carregador de bateria, o circuito opera em 250 kHz e apresenta eficiências maiores que 92% em toda a faixa de potência com um valor máximo de 97,3%. No modo driver de LED, a frequência de operação escolhida foi de 345 kHz e uma eficiência máxima de 95,8% foi obtida. Para a validação da metodologia de projeto proposta, quatro conversores com potências de 30 W em modo driver e 150 W em modo carregador foram implementados e testados em diferentes pontos de operação. Com isso, comprovou-se que, considerando um conjunto de componentes, a metodologia é capaz de determinar o melhor ponto de operação para maximizar o rendimento, e, considerando diferentes conjuntos de componentes, determinar o melhor em termos de redução da energia perdida, de forma a maximizar a autonomia do sistema.

VER TESE COMPLETA:

 https://repositorio.ufsm.br/bitstream/handle/1/25767/TES_PPGEE_2022_DUARTE_RENAN.pdf?sequence=1&isAllowed=y

Doctoral Dissertation A Three-Phase SCVD Based Boost Inverter with Low Common Mode Voltage for Transformerless Photovoltaic Grid-Connected System Department of Electrical Engineering Graduate School, Chonnam National University BY Tran Tan Tai

(Abstract)

 This study deals with a new type of inverter called a three-phase SCVD based boost inverter. The introduced structure is a combination of an SCVD network and the three-phase bridge to restrict the common-mode voltage. Therefore, the introduced inverter can produce a high output voltage from the low input voltage. The DC-bus voltage of the introduced solution stands at twice of the input voltage. Moreover, the variation in common-mode voltage can o be restricted within one-sixth of DC-bus voltage. Modeling, circuit analysis, operating principles, and a comparison between the introduced SCVD based boost inverter with the other VSIs are performed. To confirm the performance improvements of the introduced SCVD based boost inverter, a preliminary prototype of the introduced SCVD based boost inverter is built in the laboratory and the simulation studies based on PLECS environment and experimental studies are performed. Besides that, a modified SCVD based boost inverter is also introduced to step up the DC-bus voltage to triple of input voltage instead of twice of input voltage like that in the proposed SCVD based boost inverter. Furthermore, a common-mode voltage of the modified SCVD based boost inverter is x canceled through switching the four extra active-switches based on the Boolean logic function. As a result, common-mode voltage is maintained as constant at the value of 0 V during all time. Moreover, the voltage stress across additional semiconductor devices is standing at one-third of DC-bus voltage. The simulation studies based on PLECS environment prove the effectiveness of the modified SCVD based boost inverter. Finally, to validate the performance, operating principle, and feasibility of the modified SCVD based boost inverter, the experimental studies based on the laboratory prototype with a DSP F280049C are carried out. Doctoral Dissertation A Three-Phase SCVD Based Boost Inverter with Low Common Mode Voltage for Transformerless Photovoltaic Grid-Connected System Department of Electrical Engineering Graduate School, Chonnam National University BY Tran Tan Tai (Abstract) This study deals with a new type of inverter called a three-phase SCVD based boost inverter. The introduced structure is a combination of an SCVD network and the three-phase bridge to restrict the common-mode voltage. Therefore, the introduced inverter can produce a high output voltage from the low input voltage. The DC-bus voltage of the introduced solution stands at twice of the input voltage. Moreover, the variation in common-mode voltage can o be restricted within one-sixth of DC-bus voltage. Modeling, circuit analysis, operating principles, and a comparison between the introduced SCVD based boost inverter with the other VSIs are performed. To confirm the performance improvements of the introduced SCVD based boost inverter, a preliminary prototype of the introduced SCVD based boost inverter is built in the laboratory and the simulation studies based on PLECS environment and experimental studies are performed. Besides that, a modified SCVD based boost inverter is also introduced to step up the DC-bus voltage to triple of input voltage instead of twice of input voltage like that in the proposed SCVD based boost inverter. Furthermore, a common-mode voltage of the modified SCVD based boost inverter is canceled through switching the four extra active-switches based on the Boolean logic function. As a result, common-mode voltage is maintained as constant at the value of 0 V during all time. Moreover, the voltage stress across additional semiconductor devices is standing at one-third of DC-bus voltage. The simulation studies based on PLECS environment prove the effectiveness of the modified SCVD based boost inverter. Finally, to validate the performance, operating principle, and feasibility of the modified SCVD based boost inverter, the experimental studies based on the laboratory prototype with a DSP F280049C are carried out.

VIEW FULL DOCTORAL DISSERTATION:

http://www.riss.kr/search/Search.do?colName=all&isDetailSearch=N&searchGubun=true&oldQuery=&sflag=1&fsearchMethod=search&isFDetailSearch=N&searchQuery=A+Three-Phase+SCVD+Based+Boost+Inverter+with+Low+Common+Mode+Voltage+for+Transformerless+Photovoltaic+Grid-Connected+System&kbid=&pageNumber=1&query=A+Three-Phase+SCVD+Based+Boost+Inverter+with+Low+Common+Mode+Voltage+for+Transformerless+Photovoltaic+Grid-Connected+System

LINK ALTERNATIVO DOCTORAL DISSERTATION:

https://www.mediafire.com/file/ciiom9klno2j511/A+Three-Phase+SCVD+Based+Boost+Inverter+with+Low+Common+Mode+Voltage+for+Transformerless+Photovoltaic+Grid-Connected+System.pdf/file

GaN MOSFET를 이용한 유도전동기 구동용 고효율 인버터에 관한 연구 = A Study on the high efficiency inverter for driving an induction motor using GaN MOSFET by Park, Sang-Yong- Dept. of Electronic Engineering The Graduate School Hanyang University

   

A Study on the High Efficiency Inverter for Driving an Induction Motor using GaN MOSFET Park, Sang-yong Dept. of Electronic Engineering The Graduate School Hanyang University

ABSTRACT 

 It was proved in this paper that the efficiency of the inverter using GaN MOSFET ,which is regarded as a next generation power semiconductor, was much improved comparing the efficiency to the counterpart using the conventional Si MOSFET. Comparing the characteristics of GaN MOSFET to those of Si MOSFET, GaN MOSFET shows very low on resistance and very fast switching speed due to the high breakdown voltage and very small parasitic capacitances. Therefore, using GaN MOSFET as switching devices of the inverter, it is expected that the efficiency and characteristics of the inverter can be improved since the switching and conduction losses and switching noise can be reduced. In this paper, to demonstrate the superiority of GaN MOSFET to Si MOSFET, the inverter using GaN MOSFET for driving a 2.2 kW induction motor was fabricated. The design specification of the inverter fabricated is as follows: input voltage is 220 Vac, switching frequency is 20 kHz, and the operating frequency is 0 to 70 Hz. The fabricated inverter was tested and the normal operation of the inverter was confirmed. Finally the efficiency of the inverter was measured and the results of measured efficiency was compared to those of Si MOSFET inverter with the same specification as the GaN MOSFET inverter fabricated. From the comparison results, it is known that the efficiency of the GaN MOSFET inverter is superior to that of Si MOSFET inverter at the full range of load. The maximum efficiency of the GaN MOSFET inverter was measured as 98.41 %.

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http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=8f84b308625e5129ffe0bdc3ef48d419&keyword=inverter%20gan

ESTRUCTURAS DE CONVERSIÓN PARA SISTEMAS FOTOVOLTAICOS DE ALTA POTENCIA Memoria que, para optar al grado de Doctor Ingeniero Industrial, por Mikel Borrega Ayala -DEPARTAMENTO DE INGENIERIA ELECTRONICA-UNIVERSIDAD PUBLICA DE NAVARRA

 

1.2 Objetivos de la tesis

. La red eléctrica es de naturaleza alterna, con lo que si se quiere inyectar energía en la red se debe de hacer mediante corriente alterna. Sin embargo, la corriente proporcionada por un generador fotovoltaico es de naturaleza continua. Es por ello que se hace necesaria la utilización de una etapa de conversión electrónica DC/AC, denominada inversor. En las instalaciones fotovoltaicas de conexión a red se utilizan tanto inversores trifásicos, que inyectan la potencia generada a una red trifásica, como inversores monofásicos que la inyectan a una fase. Normalmente, en instalaciones de potencias inferiores a 4.6-6kW4, se utilizan inversores monofásicos. En instalaciones de más potencia, tanto domésticas como grandes plantas, se utilizan inversores trifásicos.

Esta tesis se va a centrar en los inversores fotovoltaicos de conexión a red utilizados en grandes plantas de generación eléctrica. Tal y como se ha apuntado anteriormente, estas instalaciones tienen una potencia de entre 1MW y los 247MW de la instalación más grande del mundo a día de hoy. Se suelen ubicar en lugares con una alta irradiación, aprovechando terrenos de escaso valor urbanístico o para la agricultura. El factor económico es, por lo tanto, el principal parámetros a tener en cuenta en el diseño de este tipo de instalaciones ya que se busca la mayor rentabilidad. Así, los costes de todos los elementos que componen la instalación, incluido el inversor, tienen que ser lo menor posibles. El coste del inversor en relación a la potencia del mismo, ratio €/Vat, suele ser mejor en los inversores de mayor potencia y es por ello que, en este tipo de instalaciones en las que se busca una etapa de conversión lo más económica posible, se utilizan los mayores inversores del mercado con potencias de entre 500kW y 1MW, en lugar de una cantidad mayor de inversores de menor potencia. Es precisamente el diseño de estos inversores de gran potencia el objetivo principal de esta tesis.

Cabe destacar que el hecho de que se busque la instalación más económica posible no siempre va ligado a que el inversor tenga que ser lo más barato posible. Lo importante es conseguir la mayor rentabilidad de la totalidad de la instalación, y eso requiere en ocasiones encarecer ligeramente el inversor si con ello se mejoran ciertas prestaciones del mismo que finalmente desembocan en el abaratamiento de otro elemento de la instalación, o en el aumento de la productividad de la misma.

El factor más importante que hace que las características de un inversor difieran de las de otros, es la arquitectura utilizada en cada uno de ellos. En estos inversores fotovoltaicos de alta potencia existen tres topologías principales. La primera de ellas es el Inversor Centralizado (IC). Se trata de una etapa de conversión única por la cual circula la totalidad de la potencia inyectada a la red. Por un lado entra la potencia proveniente del campo solar, que es de carácter continuo. El inversor convierte la potencia en forma alterna para poder inyectarla a la red eléctrica que es también de carácter alterno. La red eléctrica a la que se conectan este tipo de inversores de gran potencia es de tipo IT, con el neutro aislado de tierra.

VER LA TESIS COMPLETA:  https://academica-e.unavarra.es/xmlui/bitstream/2454/29278/1/04%20Tesis%20doctoral%20Mikel%20Borrega%20Ayala.pdf

Analysis, Design, and Control of a Modular Multilevel Series-Parallel Converter (MMSPC) Zur Erlangung des akademischen Grades eines DOKTOR-INGENIEURS von der KIT-Fakultät für Elektrotechnik und Informationstechnik des Karlsruher Instituts für Technologie (KIT)

Analysis, Design, and Control of a Modular Multilevel Series-Parallel Converter (MMSPC) Zur Erlangung des akademischen Grades eines DOKTOR-INGENIEURS von der KIT-Fakultät für Elektrotechnik und Informationstechnik des Karlsruher Instituts für Technologie (KIT) genehmigte

 DISSERTATION von M.Eng. Christian Korte geb. in: Gerolstein

 Vorwort 

Diese Arbeit entstand während meiner Tätigkeit als wissenschaftlicher Mitarbeiter am Elektrotechnischen Institut (ETI) des Karlsruher Instituts für Technologie (KIT). Im Rahmen einer wissenschaftlichen Kooperation hatte ich die Möglichkeit einen neuartigen Ansatz zur Realisierung des elektrischen Automobil-Antriebsstrangs zu erforschen. Dieser Ansatz, der Modular Multilevel Series-Parallel Converter (MMSPC), zieht eine umfassende Umgestaltung der elektrischen Automobil-Architektur nach sich. Aus diesem Grund habe ich mir die Aufgabe gesetzt, einen möglichst fundamentalen wissenschaftlichen Vergleich zwischen dem herkömmlichen Ansatz und dem MMSPC zu erarbeiten. Ferner habe ich mich darauf konzentriert, die Leistungsfähigkeit des MMSPC durch Regelung zu erhöhen. Ohne die durchgehende Unterstützung aus meinem privaten und beruflichen Umfeld wäre es nicht möglich gewesen, diese Arbeit erfolgreich abzuschließen. Dafür möchte ich mich bei allen Beteiligten herzlich bedanken. Insbesondere gilt dieser Dank meinem Doktorvater Prof. Dr.-Ing Marc Hiller, der es mir ermöglicht hat mit großer wissenschaftlicher Freiheit an meiner Arbeit zu forschen. Bei Prof. Dr.-Ing Dieter Gerling bedanke ich mich ebenfalls für die Begutachtung und die Übernahme des Korreferats. Zudem möchte ich mich bei Prof. Dr.-Ing Malte Jaensch und Prof. Dr.-Ing. Stefan Götz bedanken, für das entgegengebrachte Vertrauen und die große Unterstützung während meiner Tätigkeit bei Porsche Engineering. Ohne die außergewöhnliche Atmosphäre und Kollegialität am ETI wäre die Entstehung dieser Arbeit mit deutlich weniger Freude und guten Erinnerungen verbunden. Dafür bedanke ich mich bei allen Kollegen und Studenten des ETI, mit denen ich das Vergnügen hatte zu Arbeiten. Mein Dank richtet sich insbesondere an Daniel, für die viele Hilfe bei meinen Publikationen, dafür dass Du immer die Wissenschaft am ETI vorangetrieben hast und vor Allem für die ganzen unvergesslichen Erlebnisse die wir geteilt haben. Weiterhin möchte ich mich bei Firat, Patrick, Simon, Felix, Felix und Tobi für Eure andauernde Unterstützung und die großartige Zeit bedanken. Seit meiner Kindheit haben mir meine Eltern und (meistens) meine Schwester jederzeit den Rückhalt gegeben, den ich benötigte um erfolgreich meine Fortbildung und meine Promotion zu bestehen. Dafür bedanke ich mich herzlichst, denn ohne Euch hätte es nicht klappen können. Während meiner Promotion hat Ravina am meisten miterlebt, wie ich mit der Arbeit gekämpft habe. Dennoch hast Du mir immer geholfen das Beste aus mir herauszuholen und immer an meinen Erfolg geglaubt. Danke dafür und dass Du eine wundervolle Freundin bist!

VIEW FULL THESIS:

https://publikationen.bibliothek.kit.edu/1000143696/148566983