9 research outputs found
Modulation Strategies for Indirect Matrix Converter: Complexity, Quality and Performance
In general, there are two main classifications in matrix converters. The most common known type is conventional matrix converter (CMC) or direct matrix converter (DMC). The other type is indirect matrix converter (IMC). A brief review for modulation strategies are provided in this work for modulation strategies in IMC. There are several popular modulation methods for IMC such as carrier-based modulation and space vector modulation (SVM). A sinusoidal current waveform is produced on the input and output sides to implement the modulation method. In the conclusion the modulation methods will compared based on performance, theoretical complexity, and some other parameters
A Novel Globally Optimized Instantaneous Torque Ripple Minimization Method in Switched Reluctance Motors with Matrix Converter Drives
The tangential component of electromagnetic force in switched reluctance motors (SRM) produces the desired torque which fluctuates with rotor position due to the doubly saliency in physical structure of SRM. The conventional methods are insufficient to completely compensate for the intrinsic behavior due to double saliency. This dissertation proposes a novel method of eliminating the torque ripple in the instantaneous torque profile of SRM and a method to generate the precise reference phase current waveforms for even open loop operational design through global optimization. For the purpose of implementation of the proposed method, a non-sinusoidal DC matrix converter is also proposed to generate such waveforms without using multiple source voltages and to be able to use the drive in electric vehicle applications where a battery system is available for DC voltage sources. The experimentally-obtained characteristics are used for finding the optimal solution for torque ripple reduction. FEA is used to investigate the accurate EM force and its radial and tangential components using volume integration method. The proposed global optimization method can give a precise solution for this non-linear problem. Therefore a modified fast-filled method is proposed to balance out the crests and troughs of the torque ripples throughout the operation of SRMs. A set of novel reference current waveforms are generated for feed-forward torque control. Comparative analyses with the torque and current profiles of conventional methods are performed to prove the elimination of ripple up to less than 1% by using the proposed method. Therefore, it is concluded that the advanced turn-on and delayed turn-off angles with gradual rise and fall significantly eliminate the ripple. Inverter topology requirement for SRM is geometry-dependent. A multi-level converter is more suitable to generate the required position-dependent phase current. Matrix converters can be used for finer control on flexible current profiling. Therefore, a non-sinusoidal DC matrix converter is proposed to generate the required phase current waveforms from a single DC source and to accommodate the changes if required accurately. Three reduced-switching states schemes were tested with matrix converter resulting in the ripple elimination between 0.9% - 2% where 0.45% reduction is possible
Shortest Route at Dynamic Location with Node Combination-Dijkstra Algorithm
Abstract— Online transportation has become a basic
requirement of the general public in support of all activities to go
to work, school or vacation to the sights. Public transportation
services compete to provide the best service so that consumers
feel comfortable using the services offered, so that all activities
are noticed, one of them is the search for the shortest route in
picking the buyer or delivering to the destination. Node
Combination method can minimize memory usage and this
methode is more optimal when compared to A* and Ant Colony
in the shortest route search like Dijkstra algorithm, but can’t
store the history node that has been passed. Therefore, using
node combination algorithm is very good in searching the
shortest distance is not the shortest route. This paper is
structured to modify the node combination algorithm to solve the
problem of finding the shortest route at the dynamic location
obtained from the transport fleet by displaying the nodes that
have the shortest distance and will be implemented in the
geographic information system in the form of map to facilitate
the use of the system.
Keywords— Shortest Path, Algorithm Dijkstra, Node
Combination, Dynamic Location (key words
Anuário Científico – 2011 Resumos de Artigos, Comunicações, Livros e Monografias de Mestrado
Há mais de uma década que o ISEL vem firmando a sua aposta na busca e na divulgação do conhecimento científico na área da Engenharia, assentes na inovação e no desenvolvimento de novas tecnologias, procurando que os resultados alcançados nos projetos de investigação tenham impacto na indústria e na vida dos cidadãos como forma de responder às necessidades cada vez mais complexas e exigentes da sociedade no seu todo.
Nesta relação, o ISEL tem contribuído para a evolução da produção e do conhecimento científicos, assumindo, por vezes numa posição de vanguarda, ora em iniciativa própria ora em parceria com diversas instituições, quer de ensino quer do tecido empresarial.
Como forma de dar visibilidade ao trabalho desenvolvido pelos docentes (com afiliação ISEL) e alunos do ISEL, o Anuário Científico tornou-se num meio de divulgação privilegiado, estando disponível em acesso livre a toda a comunidade científica mas também a todos os cidadãos, podendo ser consultado em formato eletrónico no sítio institucional do ISEL, bem como no Repositório Científico do Instituto Polítécnico de Lisboa.1
Fazendo uma análise comparativa em relação às publicações referentes a 2009 e a 2010, constata-se que o número de publicações duplicou em 2011
Abstracts on Radio Direction Finding (1899 - 1995)
The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography).
Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM.
The contents of these files are:
1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format];
2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format];
3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion
A Comprehensive Guide to Solar Energy Systems With Special Focus on Photovoltaic Systems
This book, the most advanced and research focused text on all aspects of solar energy engineering, is a must have edition on the present state of solar technology, integration and worldwide distribution. In addition, the book provides a high-level assessment of the growth trends in photovoltaics and how investment, planning and economic infrastructure can support those innovations. Each chapter includes a research overview with a detailed analysis and new case studies that look at how recent research developments can be applied. Written by some of the most forward-thinking professionals, this book is an invaluable reference for engineers.
Key Features
Contains analysis of the latest high-level research and explores real world application potential in relation to developments
Uses system international (SI) units and imperial units throughout to appeal to global engineers
Offers measurable data written by a world expert in the field on the latest developments in this fast moving and vital subject
Readership
Energy engineers, researchers, graduate students, professors and lecturers in Engineering, scientists and engineers working in energy, industrialists and engineers working in future energy development
EUROSENSORS XVII : book of abstracts
Fundação Calouste Gulbenkien (FCG).Fundação para a Ciência e a Tecnologia (FCT)