1,720,986 research outputs found
A new basic unit for cascaded multilevel inverters with reduced number of power electronic devices
No full textIn this paper, a new topology for asymmetrical cascaded multilevel inverter is proposed. The proposed topology consists of series connection of several basic units. Reduction of number of power switches, driver circuits, IGBTs and dc voltage sources are some advantages of the proposed topology in comparison with the conventional cascaded multilevel inverters. In order to generate all output voltage levels, a new algorithm to determine the magnitudes of dc voltage sources is proposed. Finally, to verify the performance of the proposed inverter, the simulation results by using PSCAD/EMTDC software on a 33-level single-phase inverter are used
Diode Assisted Quasi Z-source Inverter with Discontinuous Current: Analysis and Simulation
No full textIn this paper, the developed topology of the diodes assisted quasi Z-source inverter (DAQZSI) is proposed. This topology is investigated in three states of two-cell DAQZSI, three-cell DAQZSI and n-cell DAQZSI. These topologies are completely analyzed and the boost factor are obtained. High value of boost factor without increasing the number of used active elements is the most important advantage of this inverter in comparison with the conventional Z-source inverter. In addition, the voltage and current equations of used capacitors, diodes and inductors are calculated. Finally, the correctness of the presented analyses is reconfirmed by using the simulation results on the two-cell DAQZSI in EMTDC/PSCAD software
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
A new developed cascaded multilevel inverter topology to reduce number of used devices
No full textIn this paper, a new developed cascaded multilevel inverter is proposed which has ability of generating a specified number of voltage levels with a reduced number of required IGBTs and DC voltage sources. To produce all even and odd voltage levels, three patterns are proposed which the magnitudes of DC voltage sources are determined based on them. After that the best proposed pattern is compared with some of presented topologies from different aspects, in order to verify the claim of reduction of used devices and find out the merits and demerits of the proposed topology. At the end of this paper, the simulation results by PSCAD/EMTDC software are demonstrated in order to validate the correct operation of the proposed topology
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
Analysis and design of switched-boost inverter in CCM, DCM and BCM operations
No full textThis paper proposes a comprehensive analysis of switched boost inverter's (SBI) voltage and current equations, using specific switching method in continuous current mode (CCM) operation. The presented switching method makes SBI proper to be used in galvanic and electrochemical applications. The boundary amount of inductor between the two CCM and discontinuous current mode (DCM) operations is calculated and also the operative parameters are determined. In addition, the diodes' and switches' voltage and current stresses, the inductor's current ripple and the capacitor's voltage ripple equations are represented which are needful to design the components. Moreover, the switching control circuit is proposed. Finally, the PSCAD/EMTDC software program results are given to show the theoretical analysis validation
A New Structure with New Algorithms for Cascaded Multilevel Inverters by Reducing Number of IGBTs
No full textCascaded multilevel inverters are usually used in a medium-voltage output. Hence, this converter has been declared as a vital substitute in the average-voltage inverter. In this article a novel structure for cascaded multilevel inverters have been proposed. Also, five algorithms are suggested to determine the amount of resources which are used in the new structure. The suggested topology has a number of benefits, including reducing the quantity of IGBTs and switches and required fee and installation area. Another benefit of the suggested structure is lower variety of the values of dc voltage sources in comparison with conventional structures. In this paper, the ability of proposed topology to produce all voltage levels with the result of the simulation is given to a17-level inverter
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
A new topology of cascaded multilevel inverter with reduced number of driver circuits and IGBTs
No full textReducing the number of required devices has a great importance in multilevel inverters area. In view of this, a cascaded multilevel inverter structure is proffered which requires the least number of components; IGBT and driver circuits. Four separate methods (algorithms) are recommended to ascertain the values of used DC voltage resources. In this paper, comparing the recommended topology with conventional structures from different aspects is done and comparison results are discussed. Simulation results of a 13-level inverter are shown in order to validate generating all voltage levels
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