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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Vliv aditiv v olověných akumulátorech pro hybridní elektrická vozidla / Effect of additives in lead-acid batteries for hybrid electric vehicles.

Klaner, Pavel January 2012 (has links)
This thesis deals with issues of the issue lead-acid batteries and their application in mode of hybrid electric vehicle. The experiment is focused on the production of electrodes to determine the effect five types of additives in negative active mass in PsoC(Partial State of Charge) mode. This simulates conditions occurring in the mode of hybrid electric vehicles (HEV).
42

Resilient and Real-time Control for the Optimum Management of Hybrid Energy Storage Systems with Distributed Dynamic Demands

Lashway, Christopher R 26 October 2017 (has links)
A continuous increase in demands from the utility grid and traction applications have steered public attention toward the integration of energy storage (ES) and hybrid ES (HESS) solutions. Modern technologies are no longer limited to batteries, but can include supercapacitors (SC) and flywheel electromechanical ES well. However, insufficient control and algorithms to monitor these devices can result in a wide range of operational issues. A modern day control platform must have a deep understanding of the source. In this dissertation, specialized modular Energy Storage Management Controllers (ESMC) were developed to interface with a variety of ES devices. The EMSC provides the capability to individually monitor and control a wide range of different ES, enabling the extraction of an ES module within a series array to charge or conduct maintenance, while remaining storage can still function to serve a demand. Enhancements and testing of the ESMC are explored in not only interfacing of multiple ES and HESS, but also as a platform to improve management algorithms. There is an imperative need to provide a bridge between the depth of the electrochemical physics of the battery and the power engineering sector, a feat which was accomplished over the course of this work. First, the ESMC was tested on a lead acid battery array to verify its capabilities. Next, physics-based models of lead acid and lithium ion batteries lead to the improvement of both online battery management and established multiple metrics to assess their lifetime, or state of health. Three unique HESS were then tested and evaluated for different applications and purposes. First, a hybrid battery and SC HESS was designed and tested for shipboard power systems. Next, a lithium ion battery and SC HESS was utilized for an electric vehicle application, with the goal to reduce cycling on the battery. Finally, a lead acid battery and flywheel ES HESS was analyzed for how the inclusion of a battery can provide a dramatic improvement in the power quality versus flywheel ES alone.
43

Sistemas de logística reversa pós-consumo: um estudo comparativo entre os setores de baterias chumbo-ácido, embalagem de óleo lubrificante e pneus

Coelho, Arnolfo Menezes 29 June 2018 (has links)
Submitted by Arnolfo Coelho (arnolfo.menezes@grupomoura.com) on 2018-07-30T21:05:37Z No. of bitstreams: 1 TA MPGC Arnolfo Menezes Versão Final R1.pdf: 1141674 bytes, checksum: e87c994b8339b250e34e46111cc83222 (MD5) / Approved for entry into archive by Simone de Andrade Lopes Pires (simone.lopes@fgv.br) on 2018-07-31T17:38:31Z (GMT) No. of bitstreams: 1 TA MPGC Arnolfo Menezes Versão Final R1.pdf: 1141674 bytes, checksum: e87c994b8339b250e34e46111cc83222 (MD5) / Approved for entry into archive by Suzane Guimarães (suzane.guimaraes@fgv.br) on 2018-07-31T17:51:27Z (GMT) No. of bitstreams: 1 TA MPGC Arnolfo Menezes Versão Final R1.pdf: 1141674 bytes, checksum: e87c994b8339b250e34e46111cc83222 (MD5) / Made available in DSpace on 2018-07-31T17:51:27Z (GMT). No. of bitstreams: 1 TA MPGC Arnolfo Menezes Versão Final R1.pdf: 1141674 bytes, checksum: e87c994b8339b250e34e46111cc83222 (MD5) Previous issue date: 2018-06-29 / As modalidades insustentáveis de produção e consumo praticadas têm sido ponto de discussões ambientais que influenciam a sociedade e, consequentemente, aspectos legais e de produção. Portanto, a gestão ambientalmente racional dos resíduos foi incluída entre as questões de maior importância para a manutenção da qualidade do ambiente natural e para o atingimento de um modelo mais sustentável de desenvolvimento. Em adição aos argumentos supramencionados, sabe-se que o aumento populacional em diversas partes do mundo, e o consequente incremento no consumo, facilmente influenciam as organizações a aumentarem sua produção, o que também aumenta tanto o consumo de matéria-prima quanto a geração de resíduos. Uma maneira de mitigar a pegada ecológica – e, inclusive, de gerar valor para a organização – está em utilizar os recursos de maneira mais sustentável, dando prioridade a processos de reuso, reaproveitamento e reciclagem de matérias-primas. E a logística reversa é um conceito que cresce em importância, já que permite às organizações, de maneira estruturada, ter acesso ao resíduo de seu produto e/ou de produtos de terceiros após o uso pelo consumidor, tornando este resíduo (em parte ou no todo) uma nova entrada no processo produtivo como matéria-prima ou insumo, ao invés de ser direcionado a lixões ou aterros sanitários. Diante desta problemática, e face à criação, no Brasil, da Política Nacional de Resíduos Sólidos, este estudo tem como objetivo descrever, analisar e comparar as práticas de logística reversa pós-consumo de três setores distintos: baterias chumbo-ácido, embalagens de óleo lubrificante e pneus. Foram verificados os modelos de funcionamento e os resultados ambientais da implementação dos sistemas de logística reversa. Para a realização do estudo, foram entrevistados representantes dos setores afim de estudar as entidades gestoras: IBER, Instituto Jogue Limpo e RECICLANIP, responsáveis pela gestão dos sistemas de logística reversa de baterias chumbo-ácido, embalagens de óleo lubrificante e pneus, respectivamente. / The unsustainable modalities of production and consumption have been the point of environmental discussions that influence society and, consequently, legal and production aspects. Sustainable waste management has been included as one of the most important issues for maintaining the quality of the natural environment and for achieving a more sustainable model of development. In addition to the above arguments, it is known that the population increases in several parts of the world, and the consequent increase in consumption, easily influence the organizations to increase their production, which also increases both the consumption of raw material and the generation of waste. One way to mitigate the ecological footprint - and even to generate value for the organization - is to use resources in a more sustainable way, giving priority to processes of reuse and recycling of raw materials. Reverse logistics is a concept that grows in importance, since it allows the organization, in a structured way, to have access to the residue of its product after the use by the consumer, making this residue (in part or in whole) a new entry in the process as raw material or input, rather than being directed to landfills. In view of this problem, and in view of the creation in Brazil of the National Solid Waste Policy, this study aims to describe, analyze and compare the postconsumption reverse logistics practices of three different sectors: lead-acid batteries, lubricating oil and tires. The operating models and the environmental performance of the sectors were verified before and after the implementation of the reverse logistics systems. In order to carry out the study, were interviewed representatives of three sectors in order to study the entities: IBER, Jogue Limpo Institute and RECICLANIP, responsible for the management of reverse logistics systems for lead-acid batteries, lubricating oil packing and tires, respectively.
44

Použití keramik v kladné aktivní hmotě olověných akumulátorů / The use of ceramics in the positive active mass of lead-acid batteries

Bureš, Michal January 2015 (has links)
Premature loss of capacity, mode of partial charge, additives, negative electrode, lead acid battery, lead-acid battery cycling, hybrid electric vehicle, traction battery, ebonex, titanium dioxide
45

Ανάπτυξη δυναμικού μοντέλου και έλεγχος ανεμογεννήτριας συνδεδεμένης στο δίκτυο και σε αυτόνομη λειτουργία εφοδιασμένη με διάταξη αποθήκευσης ενέργειας

Δημητρακάκης, Στέφανος 18 June 2014 (has links)
Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη και τη μοντελοποίηση ενός αιολικού συστήματος παραγωγής ηλεκτρικής ενέργειας βασισμένο σε σύγχρονη γεννήτρια μόνιμου μαγνήτη (PMSG). Ειδικότερα, παρουσιάζονται και αναλύονται όλα τα τμήματα που αποτελούν το αιολικό σύστημα καθώς και οι λογικές ελέγχου που ακολουθήθηκαν για την αποτελεσματική λειτουργία του. Επιπλέον, μελετάται και μοντελοποιείται μια διάταξη αποθήκευσης ενέργειας από την οποία πλαισιώνεται το αιολικό σύστημα κατά την αυτόνομη λειτουργία του. Τέλος, παρουσιάζονται και σχολιάζονται τα αποτελέσματα της προσομοίωσης της λειτουργίας του συστήματος, σε σύνδεση με το δίκτυο και κατά την αυτόνομη λειτουργία του. Για την ανάπτυξη του μοντέλου και την προσομοίωση χρησιμοποιήθηκε το πρόγραμμα Simulink/Matlab. Στο Κεφάλαιο 1 γίνεται αναφορά στο ενεργειακό πρόβλημα και μια γενική εισαγωγή στις ανανεώσιμες πηγές ενέργειας. Επιπλέον, δίνονται διάφορες πληροφορίες γύρω από την αιολική ενέργεια και αναλύονται τα πλεονεκτήματα και μειονεκτήματα της χρήσης ανεμογεννητριών. Επίσης, παρουσιάζεται η δομή μιας ανεμογεννήτριας και παραθέτονται διάφοροι τύποι ανεμογεννητριών, ενώ δίνονται και οι βασικές σχέσεις μετατροπής της αιολικής ενέργειας σε ηλεκτρική. Στο Κεφάλαιο 2 γίνεται ανάλυση κάθε τμήματος της ανεμογεννήτριας (πτερωτή, σύστημα μετάδοσης κίνησης, γεννήτρια) και παρατίθενται οι εξισώσεις που περιγράφουν τη λειτουργία τους. Επιπρόσθετα, παρουσιάζεται ο τρόπος μοντελοποίησης του κάθε τμήματος στο περιβάλλον του Simulink. Ιδιαίτερη έμφαση δόθηκε στη μελέτη της σύγχρονης γεννήτριας μόνιμου μαγνήτη καθώς παρουσιάζεται με λεπτομέρεια η δομή της καθώς και οι αρχές που διέπουν τη λειτουργία της. Τέλος, δίνονται όλα τα χαρακτηριστικά μεγέθη της ανεμογεννήτρια που χρησιμοποιήθηκε στην παρούσα εργασία. Στο Κεφάλαιο 3 αρχικά, γίνεται μια γενική παρουσίαση των στοιχείων που αποτελούν τους μετατροπείς, ενώ στη συνέχεια παρουσιάζονται οι βασικές κατηγορίες μετατροπέων που υπάρχουν και αναφέρονται μερικοί βασικοί τύποι μετατροπέων που βρίσκουν εφαρμογή σε αιολικά συστήματα γενικότερα. Έπειτα, το κεφάλαιο επικεντρώνεται στους μετατροπείς που χρησιμοποιήθηκαν στο αιολικό σύστημα της παρούσας εργασίας καθώς εξηγείται ο τρόπος λειτουργίας τους και παρουσιάζεται ο τρόπος μοντελοποίησης τους στο Simulink. Έμφαση δόθηκε στον dc/dc μετατροπέα ανύψωσης τάσης που χρησιμοποιήθηκε, όπου γίνεται διαστασιολόγηση και παρουσιάζεται μια μικρή προσομοίωση της λειτουργίας του. Τέλος, παρουσιάζεται, επίσης, το φίλτρο που τοποθετείται στην έξοδο του αντιστροφέα. Στο Κεφάλαιο 4 περιγράφονται αναλυτικά η τεχνική διαμόρφωσης εύρους παλμών (PWM) και η τεχνική της ημιτονοειδούς διαμόρφωσης εύρους παλμών (SPWM), οι οποίες και εφαρμόστηκαν για την παλμοδότηση των μετατροπέων. Στη συνέχεια, περιγράφονται αναλυτικά οι μηχανισμοί ελέγχου που εφαρμόστηκαν με τη βοήθεια PI ελεγκτών, τόσο στην πλευρά της μηχανής (dc/dc μετατροπέας ανύψωσης τάσης) όσο και στον αντιστροφέα του αιολικού συστήματος. Στο Κεφάλαιο 5 παρουσιάζονται και σχολιάζονται τα αποτελέσματα της προσομοίωσης του αιολικού συστήματος σε σύνδεση με το δίκτυο. Το σύστημα προσομοιώνεται για δύο περιπτώσεις, σε πρώτη φάση γίνεται προσομοίωση του συστήματος υπό σταθερή ταχύτητα ανέμου ίση με 12 m/s και σε δεύτερη φάση προσομοιώνεται η λειτουργία του συστήματος για βηματικές μεταβολές της ταχύτητας του ανέμου. Στο Κεφάλαιο 6 μελετάται η αυτόνομη λειτουργία του αιολικού συστήματος το οποίο, πλέον, πλαισιώνεται με μια διάταξη αποθήκευσης ενέργειας. Αρχικά, παρουσιάζεται το σύστημα αποθήκευσης ενέργειας που χρησιμοποιήθηκε. Συγκεκριμένα η συστοιχία μπαταριών της οποίας δίνονται τα χαρακτηριστικά μεγέθη, καθώς και το μοντέλο της στο Simulink. Επίσης, παρουσιάζεται και μοντελοποιείται ο dc/dc μετατροπέας δύο κατευθύνσεων ο οποίος συνδέει τη συστοιχία με το υπόλοιπο σύστημα. Στη συνέχεια, περιγράφεται αναλυτικά ο μηχανισμός ελέγχου που εφαρμόζεται στη διάταξη αποθήκευσης ενέργειας για τον έλεγχο της φόρτισης/εκφόρτισης. Στο τέλος του κεφαλαίου παρουσιάζονται τα αποτελέσματα της προσομοίωσης του αυτόνομου αιολικού συστήματος για σταθερή ταχύτητα ανέμου-μεταβαλλόμενο φορτίο και για μεταβαλλόμενο άνεμο-σταθερό φορτίο. / In this thesis, a wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG) was studied and simulated. All parts of the WECS are presented and discussed in detail. Furthermore, control strategies for the generator-side converter and the voltage source inverter are developed. The WECS is simulated both in grid connected and stand-alone mode. In the stand-alone mode, the WECS is supplied with an energy storage system for which a bi-directional buck/boost converter and control strategy was designed. Finally, simulation results are presented and performance of the system in various modes of operation is evaluated. Simulink/Matlab is used for modeling and simulating the WECS. At the beginning of Chapter 1, a discussion of energy crisis and renewable energy sources is held. Furthermore, information about wind energy has been reviewed and its benefits and drawbacks are examined. In addition, the structure of a wind turbine and the principles of converting wind energy into electricity are presented. In Chapter 2 all parts of the wind turbine are studied and its characteristics are specified. Even more, the model of every part in Simulink is presented. Theoretical background, structure and operation principles of PMSG are presented in detail. In Chapter 3, firstly a general presentation of converters components takes place. Then the major existing categories of converter are presented and some basic types of converters, which are generally used in WECS, are mentioned. Moreover, the chapter focuses on the converters that are used in this thesis, explaining the way they operate. After all, their models in Simulink are shown. Emphasis was given to the dc/dc boost converter whose parameters are calculated and its operation is simulated. Finally, there is a presentation of the filter which was placed at the output of the inverter. In Chapter 4, Pulse-width Modulation (PWM) and Sinusoidal Pulse-width Modulation (SPWM) techniques that are used in this thesis are described. Moreover, the control strategy for the generator-side converter with maximum power extraction is presented. The control strategy of the voltage sourced inverter is shown as well. In Chapter 5 simulation results of the grid connected WECS are presented and evaluated. On the first part of the presentation, the WECS is simulated for constant wind speed (12m/s), and in the second part for step-changed wind speed. In Chapter 6 the stand-alone operation of the WECS is studied and supplied with an energy storage system. Initially, there is an analysis of the energy storage system, which was used, and in particular the battery bank, whose characteristics are given. Moreover, a Bi-directional dc/dc Buck-Boost converter which is used to interconnect the battery bank to the dc-link is presented and modeled. Afterwards, there is a detailed description of the control strategy used in order to control charging / discharging of the battery bank. At the end of this chapter, simulation results of two different stand-alone operation modes are presented, one with constant wind speed and variable load and the other one with step-changing wind speed and constant load.

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