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Control method and fault tolerance operation of five-phase induction motor drive
No full textÇok-fazlı elektrik motorlar, arızalı durumlarda kullanılabilmesi, yüksek sistem güvenilirliği, faz başına göre güç azaltma, azaltılmış moment dalgalanması avantajları gibi nedeniyle üç-fazlı motorlarla karşılaştırıldığında daha cazip bir alternatif olarak değerlendirilmektedir. Bu tezde beş-fazlı asenkron motor sürücü sistemi incelenmiştir. Çok-fazlı asenkron motorların endüstrinin farklı alanlarındaki uygulamalarda tercih edilmesi, bu araştırma çalışmasının önemini net bir şekilde göstermektedir. Son yıllarda bu konuyla ilgili birçok bilimsel araştırma yapılmaktadır. Tezin metodolojisi temelde analitik ve karşılaştırmalı olmaktadır. İlk olarak beş-fazlı asenkron motrun matematiksel modeli ve beş-fazlı gerilim beslemeli inverter (Voltage Source Inverter - VSI) modeli incelenmiştir. MATLAB/Simulink'te beş-fazlı asenkron motorun alan yönelimli kontrol (Field Oriented Control - FOC) yöntemi oluşmaktadır. Simulink modeline göre, beş-fazlı asenkron motorun performansını analiz etmek amacıyla normal modunda ve arızalı çalışması durumlarda beş-fazlı elektrik sürücünün simülasyonu gerçekleştirilmiştir. Dengesiz gerilim sisteminden etkilenen farklı ariza durumları için simülasyonlar yapılmıştır ve elde edilen stator faz akımları, rotorun hızı ve elektromanyetik moment sonuçları detaylı olarak analiz edilmiştir. Ayrıca, beş-fazlı asenkron motorla karşılaştırmak amacıyla üç-fazlı asenkron motor sürücüsü incelenmiştir. Bu araştırma çalışmasının temel amacı, üç-fazlı asenkron motordan daha iyi arıza tolerans kabiliyetine sahiptir ve daha güvenilir olan beş-fazlı asenkron motorun avantajlarını sunmaktır.The multi-phase electrical machines are recognized like an interesting
alternative comparing to conventional three-phase machines due to their
advantages, such as the ability of using these machines in faulty conditions, high
overall system reliability, the reduction in the total power per phase and reduced
torque pulsations. In this thesis, it is studied five-phase induction motor drive
system. The importance of this research study is related to the fact that multi-phase
induction motors are preferred in applications in different fields of industry. In
recent years, many scientific studies have been carried out on this subject.
The methodology of the thesis is mainly analytical and comparative. Firstly,
it was studied the mathematical model of five-phase induction motor and the model
of five-phase voltage source inverter (VSI). The field oriented control (FOC)
method of five-phase induction motor was designed in MATLAB/Simulink. Based
on the Simulink model, the simulation of five-phase electric drive was realized in
normal mode and faulty conditions operation in order to analyze the performance
of the five-phase induction motor. Simulations have been performed for different
cases of faulty conditions effected by unbalanced voltage system and the obtained
results of stator phase’s currents, rotor speed and electromagnetic torque were
analyzed in detail.
Furthermore, three-phase induction motor drive was examined in order to
compare it with five-phase induction motor. The main goal of this research work is
to present the advantages of five-phase induction motor, which has better fault
tolerance capability and it is more reliable than three-phase induction motor
On the Behavior of Five-Phase Induction Motor Drive Under Normal and Faulty Conditions
No full textThis paper describes the importance and applications of multi-phase electrical machines. The components of the five-phase electrical drive were analyzed. Due to the MATLAB/Simulink model, the simulation of the electrical drive under normal mode and faulty conditions was carried out to analyze the performance of the five-phase induction motor. Several cases of faulty conditions caused by unbalanced voltage system were considered and the simulation results of stator phase’s currents, rotor speed and electromagnetic torque were analyzed in more detail. The importance of this study is related to the various applications of multi-phase machines in different fields of industry and a lot of scientific researches based on this topic. Simulation results have shown that the five-phase machine is very reliable and it has better fault tolerance due to its slightly affected by the unbalanced voltage system
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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