Analyses of MPPT algorithms in real test conditions

Maximum Power Point Tracking (MPPT) algorithms are of major importance for optimized yield in gridconnected PV systems. Many algorithms have been investigated. However, most of the works compare these algorithms based on a literature review or on simulation. This paper presents an experimental analysis of MPPT techniques: two of the simplest (Perturb & Observe and Incremental Conductance) and two of the most complex (Fuzzy Logic Controller and Particle Swarm Optimization). The results are carried out in real test conditions, with and without shadow. The power converter is based on a boost converter and a voltage source inverter. The control is implemented using Simulink® and dSPACE 1103 real-time controller board. Moreover, the MPPT techniques of three commercial string inverters are also analysed.info:eu-repo/semantics/publishedVersio

Analyses of MPPT algorithms in real test conditions

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáOs algoritmos de rastreamento do Ponto de PotênciaMáxima (MPPT) têm grande relevância para o rendimento otimizado emsistemas fotovoltaicos conectados à rede. Muitos algoritmos foram investigados. No entanto, existe uma grande dificuldade em encontrar análises comparativas com resultados experimentais entre as diferentes técnicas, já que grande parte das pesquisas se baseiam emrevisões da literatura ou em simulação. Este trabalho apresenta umanálise experimental entre quatro técnicas MPPT, que estão entre as mais discutidas na literatura: duas das mais simples (Perturb & Observe e Condutância Incremental) e duas das mais complexas (Particle Swarm Optimization e Fuzzy Logic Controller). São utilizados ainda inversores comerciais disponíveis para teste em laboratório, comobjetivo de entender qual algoritmo MPPT é utilizado, o seu funcionamento e procedimento de inicialização. Todos os algoritmos são implementados e validados durante testes experimentais, sob condições reais, as quais operam os sistemas PV. Os testes buscam ainda garantir as mesmas condições experimentais, para que a avaliação de desempenho de cada algoritmo reflita o seu real desempenho em rastrear o ponto de máxima potência. Os testes experimentais são divididos em 3: testes em condições normais, testes em condição de sombreamento parcial e testes com inversores PV comerciais. Para a sua implementação, utilizou-se uma estrutura de potência baseada em um conversor DC-DC elevador ou conversor Boost, e um inversor monofásico de ponte completa. O controle e leitura dos sinais é implementado utilizando o Simulink® e dSPACE 1103, placa controladora em tempo real. Além disso, as técnicas MPPT de três inversores comerciais também são analisados.Maximum Power Point tracking algorithms (MPPT) have great relevance for the optimized performance in photovoltaic systems connected to the grid. Many algorithms have been investigated. However, there is a great difficulty in finding comparative analyzes based on experimental results between the different techniques, since most of the research is based on literature reviews or simulation. This work presents an experimental analysis between four MPPT techniques, which are among the most discussed in the literature: two of the simplest (Perturb & Observe and Incremental Conductance) and two of themost complex (Particle SwarmOptimization and Fuzzy Logic Controller). Commercial inverters available for laboratory testing are also used in order to understand whichMPPT algorithmis used, how does it work and how is it initialized. All algorithms are implemented and validated during experimental tests, under real conditions, which operate the PV systems. The tests also seek to guarantee the same experimental conditions, so that the performance evaluation of each algorithm reflects its real performance in tracking the maximumpower point. The experimental tests are divided into 3: tests under normal conditions, tests under partial shading condition and tests with commercial PV inverters. For implementation, a power structure based on a DC-DC Boost converter and a singlephase full-bridge inverter was used. The control and reading of the signals is implemented using Simulink® and dSPACE 1103 real-time controller board. In addition, three MPPT techniques of commercial inverters are also analyzed

A Chrysoporthe cubensis enzyme cocktail produced from a low-cost carbon source with high biomass hydrolysis efficiency

Não conta o número de páginas.Low cost and high efficiency cellulolytic cocktails can consolidate lignocellulosic ethanol technologies. Sugarcane bagasse (SCB) is a low cost agro-industrial residue, and its use as a carbon source can reduce the costs of fungi cultivation for enzyme production. Chrysoporthe cubensis grown under solid state fermentation (SSF) with wheat bran has potential to produce efficient enzymatic extracts for SCB saccharification. This fungus was grown under submersed fermentation (SmF) and SSF with in natura SCB, pretreated with acid or alkali and with others carbon sources. In natura SCB induced the highest carboxymethylcellulase (CMCase), xylanase, β-xylosidase, α-galactosidase and mannanase activities by C. cubensis under SSF. In natura and washed SCB, inducers of enzyme production under SSF, did not induce high cellulases and hemicellulases production by C. cubensis in SmF. The C. cubensis enzymatic extract produced under SSF with in natura SCB as a carbon source was more efficient for lignocelulolic biomass hydrolysis than extracts produced under SSF with wheat bran and commercial cellulolytic extract. Chrysoporthe cubensis showed high potential for cellulases and hemicellulases production, especially when grown under SSF with in natura SCB as carbon source

Professores e Alunos: o engendramento da violência da escola

The school violence engendering is partially analyzed, considering the violence production in the school environment. This is a bibliographic research with quantitative and qualitative approach. Sources: 77 theses and 15 dissertations carried out in Brazil (2007 to 2012). Data collection and organization: Content Analysis. Main reference: Bernard Charlot and Pierre Bourdieu. Results: the sources showed that Brazilian teachers participate effectively in the school violence engendering, contributing to violence production in the school environment. The students are the main victims. The teacher is less affected by physical and verbal violence. The symbolic power is the most perpetrated by the teacher against the student. The school also plays a major role in it.Analisa-se o engendramento de uma face da violência da escola, tendo em vista a produção da violência em espaço escolar. Pesquisa bibliográfica quanti-qualitativa. Fontes: 77 dissertações e 15 teses produzidas no Brasil (2007 a 2012). Coleta e organização dos dados: Análise de Conteúdo. Fundamentação base: Bernard Charlot e Pierre Bourdieu. Resultados: as fontes apontaram que professores brasileiros são protagonistas na constituição da violência da escola, contribuindo para a produção da violência em espaço escolar. Os alunos são as principais vítimas dessa violência. O professor sofre menos violência física e verbal do que o aluno. A violência simbólica é a mais usada pelo professor contra o aluno. A escola também usa desse expediente

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data