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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

Akkurate modellering en syferrekenaarsimulasie van drywingselektroniese mutators met pulswydtemodulasie en nie-lineêre netwerkelemente

19 November 2014 (has links)
M.Ing. (Electrical and Electronic) / Please refer to full text to view abstract
2

Planar technology for integrated multi-kilowatt DC-DC power converters

Hofsajer, Ivan William 14 April 2014 (has links)
M.Ing. (Electrical and Electronic Engineering) / In order to increase the overall performance and reduce the cost of power electronic converters, a new technology for the manufacturing of such converters is needed. The aim of this work is to investigate the possibility of the application of planar integrated manufacturing technology, to power electronic converters. A proposal of the definitions, terminology and graphical representation of the integrated structure is discussed together with some examples. A zero-voltage-switching PWM DC-DC converter is used as a case study. A conventionally constructed converter, using conventional component technology is designed and constructed, after a complete mathematical analysis of the converter topology. A similar converter is designed and constructed using the planar integrated manufacturing technology. Full design details and procedures are given for both converters. The two manufacturing technologies are then compared from the point of view of electrical performance, as well as some other aspects.
3

The computer-aided design of voltage source inverters

Swanepoel, Patrick Hendrik 13 March 2014 (has links)
D.Ing. (Electrical and Electronic Engineering) / This thesis presents a series of analyses developed for several voltage source inverter topologies, which are indispensable in aiding the understanding and the design of these circuits. It describes the groundwork that is required for the development of custom design software for voltage source inverters. The different circuits that can be designed by using this program, are analyzed using conventional circuit analysis techniques. The equations are used to simulate the switching behaviour and to specify the required or recommended ratings of the main devices. The custom design program can be used to design three different topologies of voltage source inverters: a) hard switching (snubberless) six pulse bridge; b) hard switching (snubberless) six pulse bridge, equipped with a simple voltage clamp; and c) soft switching (snubbed) six pulse bridge, equipped with a conventional dissipative snubber circuit. The snubberless behaviour of a voltage source inverter leg is both experimentally and analytically investigated. Approximate equations are formulated which can be used to. determine the peak ratings of the main devices in the inverter, taking the reverse recovery of the freewheel diodes into account. The snubberless behaviour of an inverter leg, equipped with a simple voltage clamp across the dc link, is experimentally and theoretically investigated. Equations for design and determining the required peak ratings of the main devices are developed. It is shown that the simple voltage clamp can operate in two different modes, either as a fast discharging or as a slow discharging voltage clamp and that the ranges of applicability of thetwo modes of operation are different. Design rules for both modes of operation are presented. In order to develop the design equations for a snubbed inverter leg a suitable topology had to be identified first. A method for objectively comparing different inverter toplogies is proposed in this thesis, according to which the minimum on- and off-states of the main devices in the different topologies are compared for identical applications. This method is used to compare four different snubbed voltage source inverter topologies both theoretically and experimentally. As both methods indicate that the conventional snubber circuit allows the highest PWM switching frequency of the uncontrolled snubber circuits, this circuit is further investigated in its dissipative topology to develop the equations required for simulation and for inclusion in the program. The influence of snubber circuits on inductive inverter loads is also investigated. It is shown that for normal snubber sizes the effect of dead time forms the larger part of the output voltage distortion and that the effects of the snubber elements are normally of secondary importance. The effect of asymmetry of a specific snubber circuit on inverter loads is investigated and it is found that it introduces a de component in the output voltage. Finally the application of linear snubbers to switches that exhibit tail-forming characteristics is analyzed and optimized. The results allow the designer to minimize the total losses of the converter by identifying the optimal snubber size. The theoretical results are experimentally verified
4

Interference characterization in unlicensed national information infrastructure (U-NII) band /

Masood, Zafar, January 1900 (has links)
Thesis (M.Eng.) - Carleton University, 2001. / Includes bibliographical references (p. 81-84). Also available in electronic format on the Internet.
5

Störningshantering för analog elektronik i en blodperfusionsmätare / Interference Management for Analog Electronics in a Blood Perfusion Monitor

Olergård, Jonathan, Ingeberg, Karoline January 2020 (has links)
Denna rapport utreder skärmning som en metod för att minska störningsupptaget hos en blodperfusionsmätare, och därmed öka dess pålitlighet vid medicinsk användning. Ett nytt kretskort för den analoga elektroniken skapades för att underlätta skärmningen, och samtidigt analyserades kretsens karakteristik och anpassades efter behov. Beräkningar och simuleringar utfördes för att undersöka kretskortets teoretiska störningspåverkan, och jämförelser mellan ett skärmat och ett oskärmat kort visar att skärmning gör att kretskortet tar upp markant mindre störningar. Praktiska tester planerades men utfördes inte eftersom COVID-19-epidemin orsakade tidsbrist. / This report examines shielding as a method to reduce interference absorption in a blood perfusion monitor, and consequently increase its reliability in clinical use. A new circuit board for the analog electronics was created to facilitate shielding, and simultaneously the circuit’s charac­teristics were analyzed and adjusted where necessary. Calculations and simulations were made to examine the circuit board’s theoretical interference impact, and com­parisons between a shielded and an unshielded board shows that shielding causes the circuit board to absorb noticeably less interference. Practical tests were prepared but not per­formed because the COVID-19 epidemic caused lack of time.
6

Enhancing Creative, Learning and Collaborative Experiences through Augmented Reality-compatible Internet-of-Things Devices

Pashin Farsak Raja (15348238) 29 April 2023 (has links)
<p>The "Maker Movement" is a cultural phenomena rooted in DIY culture, which stresses making devices and creations on your own rather than purchasing it ready-made. At the core of the Maker Movement, is the "Maker Mindset"; a collection of attitudes, beliefs and behaviors that emphasize the importance of creativity, experimentation and innovation in the learning process. Since the Maker Mindset embodies constructionist principles at its core that push makers to experiment and problem-solve by collaborating with fellow makers through hands-on activities, it can be said that these activities comprise of Creative, Learning and Collaborative experiences. While Internet-of-Things devices have long been used to enhance these activities, research pertaining to using Augmented Reality in tandem with IoT for the purpose of enhancing experiences core to the Maker Mindset is relatively unexplored. Three different systems were developed with the goal of addressing this -- MicrokARts, ShARed IoT and MechARspace. Each system focuses on enhancing one of the three core experiences through AR-compatible IoT devices, whilst ensuring that they do not require prerequisite knowledge in order to author AR experiences. These systems were evaluated through user studies and testing over a variety of age-groups, with each system successfully enhancing one core experience each through the use of AR-IoT interactions.</p>

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