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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.
1

Avbrottsfri Kraft med användning av ultrakondensatorer

Bergkvist, Jonas, Gustafsson, Fredrik January 2014 (has links)
The supply of uninterruptible power can be applied to many areas where continuous operation is highly prioritized. The application of uninterruptible power for motor operation is facilitated using a frequency converter. Direct current operated frequency converters can be applied directly to the power reserve which removes the need for additional power-converting. Batteries have long constituted the power reserve but advancements in the development of ultracapacitors have created a viable substitution. Ultra-capacitors have high energy storing capabilities and can be applied to high power applications. Maxwell is a leading manufacturing company of ultracapacitors and pro-vide different modules with built-in solutions for voltage balancing. Uneven voltages between series-connected capacitors is a phenomenon caused by vary-ing capacitance. A configuration containing Maxwell’s 56V module is created and constitutes the power reserve in the simulations. The discharge simulation shows a significant current that could damage the system. A current limiting transistor is introduced in the circuit to provide a safer course of discharge. The result of the simulations confirms that the application of ultracapacitors in uninterruptible power for motor operation is viable.
2

Energibesparingspotential i UPS-system : Byggnad 13 i SÄS / Energy saving measures in UPS-system : Building 13 in SÄS

Diaz, Damaris, Johansson, Margaretha January 2009 (has links)
Arbetet utfördes för Västfastigheter på Södra Älvsborgs Sjukhus i Borås. Studiengenomfördes i byggnad 13 där dagens UPS-aggregat börjar bli överbelastat. UPS:en i dennabyggnad har 120kVA kapacitet och försörjer med avbrottsfri kraft övriga avdelningar.Studien gjordes på följande avdelningar: Röntgenklinik, MAVA, KAVA, HIA, Dialys,Medicinavdelning 4, Dagkirurgi, Hudmottagning och AVC (Akutvårdcentral). Syftet meddetta examensarbete är att hitta orsakerna till att befintligt UPS-system är överbelastat ochvilka åtgärder som kan vidtas för att komma till rätta med problemet. Metoden har varit attgöra en grundlig inventering av lokalernas utformning samt en analys av personalenskunskaper i korrekt anslutning av el-förbrukande apparater.Resultatet visar att personalens kunskaper i hur man prioriterar rätt anslutning av elförbrukandeapparater är bristfällig, samt att förutsättningarna för att alltid kunna göra enkorrekt anslutning ibland saknas p.g.a. att korrekt vägguttag inte är åtkomlig.
3

Konstruktion av UPS-modul / Design of an UPS module

Olsson, Fredrik January 2002 (has links)
This master thesis describes the development of an UPS module. UPS is an acronym for Uninterruptable Power Supply. The UPS module has been developed at the company AerotechTelub AB. The UPS module delivers the necessary voltage and current in case of a power interrupt. If a power interrupt occur, the computer system has one to three minutes available to store data and shut down correctly. The UPS module consists of two parallel systems. Every system is built out of four parts. Part one consists of batteries and safety circuits, part two charges the batteries, partthree is a control unit, and part four delivers the voltage and current. The delivered voltage is 5 V and the current is 4 A. Tests and verifications showed that the UPS module could supply a computer system with power for about one minute. The tests have been performed in a lab at AerotechTelub AB. The UPS module is supposed to be mounted in a cassette. The cassette is then inserted in the computer system through a hole in the chassis. Thereby an opening of the computer system is avoided when the module is connected.
4

Konstruktion av UPS-modul / Design of an UPS module

Olsson, Fredrik January 2002 (has links)
<p>This master thesis describes the development of an UPS module. UPS is an acronym for Uninterruptable Power Supply. The UPS module has been developed at the company AerotechTelub AB. The UPS module delivers the necessary voltage and current in case of a power interrupt. If a power interrupt occur, the computer system has one to three minutes available to store data and shut down correctly. </p><p>The UPS module consists of two parallel systems. Every system is built out of four parts. Part one consists of batteries and safety circuits, part two charges the batteries, partthree is a control unit, and part four delivers the voltage and current. The delivered voltage is 5 V and the current is 4 A. </p><p>Tests and verifications showed that the UPS module could supply a computer system with power for about one minute. The tests have been performed in a lab at AerotechTelub AB. </p><p>The UPS module is supposed to be mounted in a cassette. The cassette is then inserted in the computer system through a hole in the chassis. Thereby an opening of the computer system is avoided when the module is connected.</p>
5

Implementering av PV-system på Trafikverkets teknikhus / Implementation of PV-systems at the Swedish Transport Administration’s signal boxes

Eriksson, Jimmy, Klasson, Niklas January 2021 (has links)
Solcellstekniken har funnits sedan lång tid tillbaka och har med en kontinuerlig utveckling vuxit fram till att bli ett rimligt alternativ för kraftförsörjning. Fördelen med solpaneler är dess installationsmöjligheter vilket tillåter installation på outnyttjade ytor så som fasader och tak. Västlänken är ett stort pågående projekt i Göteborg, projektet innefattar byggnation av nya tågstationer och förläggning av ny järnväg. Detta innebär upprättning av nya teknikhus i anslutning till järnvägen. I samband med detta väcker Sweco Sverige frågan om hur takytorna bäst kan användas på dessa teknikhus. Syftet med arbetet är att tillsammans med Sweco undersöka vilken effekt som kan genereras av en solcellsanläggning som installeras på teknikhus som är belägna i Göteborg, huruvida installation av ett PV-system är möjlig med den befintliga utrustningen som finns i ett teknikhus och hur stor del av utrustningen i ett teknikhus som kan drivas av den genererade effekten från PV-systemet. För beräknandet av potentiell uteffekt från PV-system användes ett simuleringsprogram framtaget av Energiforsk AB. Gällande installationsmöjligheter fördes direktkontakt med företaget som levererar rectiverters till Trafikverket. Resultatet visar att effekten från ett PV-system är direkt beroende av installationsytan samt verkningsgraden på solcellsmodulerna där uteffekten varierar från 0,10 kW vid lägst verkningsgrad och minst installationsyta till 1,62 kW vid högst verkningsgrad och störst installationsyta. Installation av ett PV-system är ej genomförbar till den befintliga utrustningen i teknikhusen utan måste kompletteras med tilläggsmoduler och solladdare för att systemet ska fungera på ett tillfredställande sätt. Med resultatet kunde lasteffekten för den avbrottsfria kraften och uteffekten från PV-systemet jämföras för Scenario 1 och Scenario 2, då det var för dessa två scenarier som lasteffekten var känd. Andelen av lasteffekten för den avbrottsfria kraften som kan tillgodoses av ett PV-system beräknades till 1,6 % ̶ 10,1 % för Scenario 1 och 2,3 % ̶ 18,2 % för Scenario 2. / Solar cell technology has been around for a long time and has with continuous development grown to become a viable alternative for power supply. The advantage of solar panels comes with the possibilities for installations on surfaces such as facades and roofs. Västlänken is a large ongoing project in Gothenburg, the project includes the construction of new train stations and the construction of a new railway. This includes the establishment of new signal boxes along the railway. In conjunction with this, Sweco Sweden has raised the question of how to best utilize the roof of these signal boxes. The purpose of this thesis is, in cooperation with Sweco Sweden, to investigate the potential output power that can be generated by a photovoltaic system once installed on the signal boxes located in Gothenburg, whether installation of a PV system is possible with the existing equipment in a signal box and how much of the equipment in the signal box that can be powered by the PV-system. For the calculation of potential output power from PV-systems, a simulation program designed by Energiforsk AB was used. Regarding the installation options a direct contact with the company that supplies rectiverters to the Swedish Transport Administration was established. The results shows that the output power of PV-systems depends on the installation area and the efficiency of the photovoltaic modules. The output power varies from 0.10 kW at the lowest efficiency and the smallest installation area to 1,62 kW at the highest efficiency and largest installation area. Installation of a PV-system is not feasible with the existing equipment in the signal boxes as additional modules and solar chargers are needed for a working system. With the result, the load for the uninterruptible power and the output power from the PV system could be compared for Scenario 1 and Scenario 2, as the load was known for just these two. The part of the load that can be met by the PV-system was calculated to be 1,6 % ̶ 10,1 % for Scenario 1 and 2,3 % ̶ 18,2 % for Scenario 2
6

Elkvalitetsmätning på en av Trafikverkets signalanläggningar inom ERTMS : En undersökning av elkvalitet

Poppe, Sebastian January 2018 (has links)
The thesis work was carried out within the Swedish Transport Agency's ERTMSproject to assist in deciding on the power supply of the facilities along the railways related to the project. This work applies to areas such as the implementation of the new rectifier, the Rectiverter, and power supply design with focus on redundancy and the overall electricity quality. The work was carried out by processing data from one week's power quality measurement at one of the signal plants where there was an installed Rectiverter. The results were set against current standards and causes of events discussed. The work indicates that the tested facility where power quality was measured meets the applicable standards. However, measures can be made to increase the efficiency of the facility, concerning both redundancy and direct power losses. This refers to the choice of power supply at facilities around the country and the conversion of AC to DC before the UPS and DC to AC-voltage after UPS to the Rectiverter. In chapter one terminology and abbreviations are listed. Chapter two contains an introduction to the report where background, purpose and objectives are formulated. Theory of power quality concepts, data processing, prevailing standards and information about the facilities of the Swedish Transport Administration can be found under chapter three. In chapter four, the methodology used for the power quality measurement and how it was carried out is presented. This includes the collection of sources, used equipment, practical set-up and used method for analysis. In chapter five, the results from the measurement are presented, which are then discussed further in the discussion (chapter six). The report is then summarized with conclusions and suggestions for further work in chapters seven and eight.

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