The subject of this thesis is a design of a precision dual channel laboratory power supply with output voltage range from 0 to 30 V and adjustable current limit up to 1 A. The proposed solution is based on linear regulators and input voltage switching system to minimize power dissipation. Galvanically isolated channels of the power supply share the same microcontroller that processes the user inputs. Microcontroller code allows the calibration of the device or it’s communication with computer. The cover of the device is designed with good cooling performance and 3D printing manufacturing method in mind. The properties of the designed laboratory power supply are verified by the final test measurements.

Die elektrische Energieform gewinnt im Kraftfahrzeug wegen ihrer Nutzungsvielfalt und sehr guten Steuerbarkeit für die Realisierung neuartiger Funktionen zunehmend an Bedeutung. Voraussetzung für ihren Einsatz ist eine zuverlässige und effiziente Bereitstellung durch das Kfz-Energiebordnetz. Dafür ist ein intelligentes Energiemanagement erforderlich, welches mit geeigneten Strategien die Leistungsflüsse im Energiesystem koordiniert. In dieser Arbeit werden die beiden Entwurfsziele der Zuverlässigkeit und der Effizienz bei der Entwicklung von elektrischen Energiemanagement-Strategien systematisch betrachtet. Es erfolgt eine Beschreibung und Zuordnung der einzelnen Ziele und Maßnahmen anhand der Energieflüsse und Wirkungsketten. Ein Schwerpunkt bildet dabei die Beherrschung von Lastwechseln im Bordnetz. Für Aussagen hinsichtlich einer effizienten Erzeugung elektrischer Energie erfolgt eine Untersuchung der Energiewandlungskette anhand analytischer Methoden und mit Hilfe einer simulationsgestützten Optimierung. Ein weiterer Fokus der Arbeit liegt in der Betrachtung zur Anwendung ökonomischer Modelle für eine Energiekoordination. Es werden die theoretischen Grundlagen der Mikroökonomie zusammengestellt und mögliche Funktionsstrukturen eines einseitigen und zweiseitigen Allokationsmechanismus verglichen und bewertet. Abschließend zeigen experimentelle Untersuchungen an einem Bordnetzprüfstand zum Lastwechselverhalten und die Integration eines Energiemanagement-Systems den praktischen Bezug zum realen System.

Trafikverket har genom en kapacitetsutredning och nationell plan fastslagit att de ska satsa på att möta framtida efterfrågeökning av transporter genom att effektivisera den befintliga infrastrukturen i första hand, eftersom utbyggnad är väldigt kostsamt och tar lång tid. För det allmänna nätet har begreppet och konceptet intelligenta elnät diskuterats sedan 2005 som ett sätt att effektivisera användningen av näten för att möta nya politiska krav som innebär en energiomställning samt ökad involvering från kunder. Då detta är ett vedertaget koncept för det allmänna nätet blev det relevant att undersöka hur förutsättningar och behov för ett liknande koncept till järnvägens banmatningssystem kunde tänkas se ut. Målet för studien är därför att identifiera potentialen i att utveckla ett liknande koncept för banmatningssystemet som intelligenta elnät är för det allmänna nätet, men också att föreslå lösningar från dagens tillgängliga intelligenta tekniker. För ÅF Infrastructure AB är målet med examensarbetet att utöka kunskapen på området. Av denna anledning blev syftet med examensarbetet att undersöka just förutsättningar och behov av intelligenta elnät till järnvägens banmatningssystem genom en jämförelse med det allmänna nätet samt en situationsanalys av norra malmbanan. Förutsättningarna beskrivs från en litteraturstudie av forskningen och marknaden samt intervjuer med representanter från systemägarna Trafikverket och Vattenfall. Behovet av intelligenta tekniker till banmatningssystemet beskrivs av en statistisk analys gjord på sträckan mellan Stenbacken och Tornehamn på norra malmbanan i Norrbotten. Resultatet från litteraturstudien visar att forskningen kring intelligenta banmatningssystem mestadels är applikationsinriktad och det beskrivs som ett kaos av applikationer som saknar en grundstomme i ett definierat ramverk. Det finns dock en studie som definierat funktioner till ett koncept kring intelligenta järnvägssystem som tar ett helhetsgrepp om järnvägssystemet och föreslår funktioner som forskningen kan tänkas fokusera på. På marknaden har det uppstått tvärvetenskapliga samarbeten mellan IT-bolag och järnvägsbolag för att ta fram integrerade intelligenta tekniker. Idag finns exempel på energieffektiva tåg, aktiv kompensering av övertoner och reaktiv effekt samt lagringsenheter som hanterar återmatning av effekt. Övertoner, reaktiv effekt och återmatning av effekt är alla parametrar som gör banmatningssystemet ineffektivt idag. Resultatet från intervjuerna visar att Vattenfall ser på intelligenta elnät som det framtida elnätet och har börjat implementera det. Trafikverket ser inte på det framtida banmatningssystemet inom ramen av ett koncept så som intelligenta elnät, men ökar informationsinsamlingen för att skapa förståelse kring systemet. Trafikverket var också del av ett europeiskt samarbete för att skapa ett intelligent energihanteringssystem med interoperabilitet mellan länderna och så har de infört överordnad styrning av effekt med goda resultat. De utvecklar alltså elnäten i samma riktning, där Vattenfall gör det inom ramen för intelligenta elnät medan Trafikverket inte har ett definierat koncept som framtidsscenario. Den statistiska analysen indikerar att den aktiva effekten mellan Stenbacken och Tornehamn slår i taket för maxgräns med dagens trafik, så om trafiken ska utökas som planerat behöver systemet effektiviseras eller byggas ut. Analysen visar också att återmatad effekt tas upp av andra tåg på sträckan, vilket leder till minskad utmatad effekt men högre ledningsförluster. Slutligen visar analysen hur viktigt det är att kvalitetssäkra insamlingen av data. Studien var svår att genomföra på grund av avsaknad av parametrar och osäkerheter kring hur de tagits fram. Sammanfattningsvis visar studien att det finns förutsättningar för ett intelligent banmatningssystem då forskningen efterfrågar ett konceptuellt ramverk i ett kaos av applikationsforskning, men som också börjat närma sig just detta. Dessutom finns intelligenta tekniker på marknaden samt en systemägare som utökar informationsinsamlingen och bidrar till utvecklingen via europeiskt samarbete. Den statistiska analysen visar att det finns ett behov av intelligenta tekniker för att kunna utöka trafiken på norra malmbanan samt ett behov av att kvalitetssäkra insamlingen av data. En föreslagen lösning återfinns inom ramen för intelligenta järnvägssystem med enheter som fångar upp återmatad effekt, vilket skulle minska överföringsförlusterna och osäkerheten kring vart i systemet effekten tar vägen och hur systemet påverkas av den. Om trafiken kunde optimeras med hänsyn till effekttoppar skulle trafiken på norra malmbanan kunna utökas utan att taket för maxgräns slås i då denna gräns endast nåddes, eller var nära att nås, vid några få tillfällen. / The aim of this thesis was to investigate the possibility and need of smart grids to the railway power supply system. The possibilities were investigated through a literature study and interviews, which resulted in a systems perspective of research, market and system, related to smart grids and intelligent transportation systems. The results then constituted a basis for a comparison between smart grids for the national grid and smart grids to the railway power supply system. The need of smart grids to the railway power supply system was investigated through a case study of statistical analysis. The case study was located to the most northern railway in Sweden between Stenbacken and Tornehamn. This thesis concludes that the research and market are focused on developing technical applications to create an intelligent railway transportation system but lacks a well-defined concept like the smart grid concept for the national grid. The owner of the railway power supply system, Trafikverket, is planning on increasing the amount of data collected from the system and has participated in a European collaboration to set standards for an interoperable energy management system. The case study indicates a need to make the railway power supply system more efficient or expand the power grid to be able to meet future requirements of more traffic. With regards to Trafikverkets method of making the system more efficient as a first option to increase capacity, this study suggests to do this with smart grids.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The use of power electronic converters provides a more efficient, accurate and dynamic solution to reactive compensation. In this thesis the application of power electronic converters to shunt reactive compensation will be discussed. In particular voltage dips and voltage unbalance are considered as both can be mitigated by means of shunt reactive compensation. A pre-existing uninterruptible power supply is adapted to operate as a shunt reactive compensator. The uninterruptible power supply consists of a 250 kVA three phase voltage source inverter. The modifications are limited to software and control algorithms that do not alter the normal operation of the uninterruptible power supply. Control algorithms are designed and discussed in detail. A typical double loop control strategy is implemented on the power electronic converter. The inner loop consists of a dead-beat current controller. The outer loop consists of three proportional and integral controllers controlling the DC-bus voltage, AC voltage and voltage unbalance respectively. Voltage dips and unbalance are compensated for using only reactive power. Focus is placed on producing a result can be used easily in practice. / AFRIKAANSE OPSOMMING: Drywings elektroniese omsetters wat gebruik word vir newe reaktiewe kompensasie lewer meer effektiewe, akkurate en dinamiese resultate. In hierdie tesis word die toepassing van drywings elektroniese omsetters vir newe reaktiewe kompensasie bespreek. Daar word meer spesifiek na spannings duike en spannings wanbalans gekyk aangesien albei met newe reaktiewe kompensasie verminder kan word. ’n Bestaande nood kragbron is aangepas om as n newe reaktiewe kompenseerder te funksioneer. Die nood kragbron bestaan hoofsaaklik uit ’n 250 kVA drie fase omsetter spanningsbron. Die aanpassings is beperk tot sagteware en beheer algoritmes wat nie die oorspronklike funksionaliteit van die nood krag bron beinvloed nie. Beheer algoritmes word ontwerp en deeglik bespreek. ’n Tipiese dubbel lus beheer strategie word op die drywings elektroniese omsetter toegepas. Die binnelus bestaan uit ’n voorspellende stroom beheerder. Die buite-lus bestaan uit drie proportioneel en integraal beheerders wat onderskeidelik die GS-bus spanning, WS spanning en spanning wanbalans reguleer. Spannings duike en wanbalans is verminder deur slegs reaktiewe drywing te gebruik. Die doel was ook om ’n prakties bruikbare resultaat te lewer.

Ce mémoire de thèse est consacré à la mise en place d'un système opto-électronique générique basé sur une liaison toute optique bidirectionnelle de 10km. L'architecture étudiée et développée est dédiée à l'extension d'un observatoire câblé de fond de mer afin d'atteindre de nouvelles zones d'exploration. Les travaux de recherche rapportés dans ce manuscrit présentent la réalisation d'un démonstrateur, qui permet la récupération de données, issues d'un instrument connecté à un module opto-alimenté, via une seule fibre optique où transitent simultanément deux voies de données en bande C et la puissance optique d'alimentation (à 1480nm) égale à 33dBm permettant de récupérer 180mW électrique sur le module opto-alimenté.Le contexte de cette thèse de doctorat est présenté au travers d'un état de l'art sur les moyens utilisés pour l'observation des océans et sur les systèmes électroniques à faible consommation. Après un rappel des caractéristiques essentielles de l'architecture de la liaison optique préalablement établie, nous nous concentrons sur la structure opto-électronique qui a pour but d’assurer la communication entre l’observatoire et l’instrument déporté de l’extension. La définition du cahier des charges a abouti au choix du capteur (hydrophone), du débit des données (5Mbit/s) et du protocole de communication (SPI 3-fils) utilisé entre les deux modules opto-électroniques, chacun à une extrémité de la fibre optique. L'effort a été porté sur la conception d'un module opto-alimenté faible consommation (66mW) où s'intègre l'instrument. Tout au long de ce document, les choix technologiques retenus lors de la conception des deux modules opto-électroniques sont argumentés. Le banc d'essai du démonstrateur a permis de valider la conception de cette extension et d'évaluer la qualité de la transmission des données (BER inférieur à 10-6). Le fonctionnement d'un premier prototype destiné à être marinisé a été présenté au travers de la détection et de la transmission de signaux acoustiques générés en bassin d'essai. De manière à rendre le système encore plus générique, une solution alternative à base d'un FPGA, permettant l'utilisation d'une interface SPI 4-fils sans modifier la liaison optique a été présentée et validée. / This PhD thesis is devoted to the design of an opto-electrical and generic system which uses a 10km long all-optical and bidirectional link. The studied and developed system is dedicated to extend a current cabled seafloor observatory, in order to reach new exploration areas. The research work described in this thesis presents the development and the realization of a demonstrator. This later collects data from an instrument connected to its optically powered unit. The optical power supply (33dBm at 1480nm), which provides up to 180mW electrical for the optically powered unit, and the optical data in C band, are transmitted simultaneously through the same single optical fiber.The thesis context is first presented through an overview of ocean observation systems and low consumption electronic devices. After a brief review on the main characteristics of the optical architecture, we focused on the opto-electrical structure which permits the communication between the observatory and the remote instrument. The desired requirements have led us to the choice of the sensor (hydrophone), the data bit rate (5Mbit/s) and the communication protocol (SPI 3-Wire) used between both opto-electrical units, each one located at the both ends of the optical link. A special attention was devoted to the conception of the optically powered which must be low power consumption (66mW). All along this document, technical choices involved in the realization of both opto-electrical units are presented. We could evaluate the performance of the data transmission (BER less than 10-6) by using a demonstrator's test bench. Then, a first prototype designed for the ocean environment was presented through experimental measurements. Those tests were conducted in a test pool and have consisted in the detection of acoustic signals. In order to increase the range of compatible instruments, an alternative solution based on a FPGA was described and approved. This new design allows the SPI 4-Wire to be employed without any change of the current optical architecture.

Thesis (D. Tech. Engineering : Electrical ; Dept. Applied Electronics and Electronic Communications) -- Vaal University of Technology / Two methods to convert an AC current source to an AC voltage source are presented. Both methods make use of a current transformer to provide energy extraction from the main system while maintaining galvanic isolation between the main system and the output system. Control is via a pulse width modulation scheme in both instances. The ftrst method uses a storage element to provide a DC voltage, which feeds an inverter that supplies the AC load with a voltage source. The second method does not use a storage element but is a direct AC current source to AC voltage source converter employing a current transformer. This has not been done before. A possible application of this study is in the extraction of power from high voltage transmission lines without the conventional substation and rural grid to supply small users such as the telecommunication industry.

M. Tech. (Engineering Department Applied Electronics and Electronic Communication, Faculty of Engineering) Vaal University of Technology / This study presents the design of a proton exchange membrane fuel cell stack that can be used to replace conventional sources of electrical energy in an uninterruptible power supply system, specifically for use in the telecommunications industry. One of the major concerns regarding the widespread commercialization of fuel cells is the high cost associated with fuel cell components and their manufacturing. A fuel cell design is presented in which existing, low-cost, technologies are used in the manufacture of cell components. For example, printed circuit boards are used in the manufacturing of bipolar flow plates to significantly reduce the cost of fuel cells. The first objective was to design, construct and test a single fuel cell and small fuel cell stack in order to evaluate the use of printed circuit boards in bipolar plate manufacturing. Since the use of copper in a fuel cell environment was found to reduce the lifetime of the cells, the bipolar plates were coated with a protective layer of nickel and chrome. These coatings proved to increase the lifetime of the cells significantly. Power outputs of more than 4 W per cell were achieved. The second objective was to analyze a small fuel cell stack in order to obtain a model for predicting the performance of larger stacks. A mathematical model was developed which was then used to design an electronic circuit equivalent of a fuel cell stack. Both models were adapted to predict the performance of a fuel cell stack containing any number of cells. The models were proven to be able to accurately predict the performance of a fuel cell stack by comparing simulated results with practical performance data. Finally, the circuit equivalent of a fuel cell stack was used to evaluate the capability of a switch mode boost converter to maintain a constant voltage when driven by a fuel cell stack, even under varying load conditions. Simulation results showed the ability of the boost converter to maintain a constant output voltage. The use of supercapacitors as a replacement for batteries as a secondary energy source was also evaluated.

A research report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the degree of Master of Science in Engineering, Johannesburg, August 2017 / The objective of this research work is to investigate the use of a high reliability micro grid to supply emergency electrical power to a nuclear facility following loss of offsite power (LOOP) accident. Most of the nuclear facilities around the world utilize diesel generators and battery banks as emergency power to back up the grid power supply. This power supply configuration represents the concept of the micro-grid system. The research work proposes reliability improvement of the emergency power supply by introducing diverse energy sources and energy storage systems. The energy sources and storage systems that were investigated include renewable energy sources, decay heat recovery system and large scale energy storage systems. The investigation results presented include information on the suitable energy sources and energy storage system, establishment of the reliable architectural layout and evaluation of the micro-grid system in terms of capacity adequacy and reliability. / XL2018

Certaines applications haute température telles que le forage, l’aéronautique ou l’aérospatial, amènent à repenser la conception des alimentations isolées permettant la commande des éléments de puissance. Ce mémoire s’articule autour de l’étude de la faisabilité et de l’enfouissement d’un convertisseur isolé possédant une forte isolation statique (10kV) et dynamique (<10 pF), pouvant travailler sous de hautes températures (>250°C), dans les gammes de tension de sortie de la dizaine de volts et de puissance de l’ordre du Watt. Pour ne pas être contraint par la température de Curie d’un matériau magnétique, cette alimentation DC/DC se base sur un transformateur à air. Dans un premier temps, cette thèse détaille l’origine, la mesure et l’estimation des éléments du modèle électrique choisi pour le transformateur. Ensuite, afin de maximiser la transmission de puissance, nous constituons un système résonnant en ajoutant des condensateurs en parallèle ou en série avec le transformateur, puis nous développons une méthode permettant d’accorder l’ensemble. La comparaison entre les topologies nous amène ensuite à choisir compensation série-série. Puis nous constatons que la technologie choisie pour les condensateurs, la contrainte d’isolation statique et dynamique peuvent diviser par plus de deux la puissance transmise au travers d’une surface. Enfin, nous abordons comment redresser et réguler la tension de sortie sans affecter la résonnance ou l’isolation apportée, tout en minimisant les pertes générées. Une dernière partie montre que, moyennant un système de dissipation un processus de fabrication adapté, il est possible d’intégrer la structure complète sur silicium / High temperature applications such as deep drilling, aeronautics or aerospace, lead to rework the isolated power supplies used for the control of the power elements. This work study the feasibility of an embedded converter with high static (10kV) and dynamic (<10 pF) insulation, able to work under high temperatures (> 250 ° C), in the ranges of dozens volts for the output voltage and several Watt of transmitted power. To avoid being constrained by a magnetic material Curie temperature of, we use a coreless transformer based DC/DC power supply. First of all, this thesis details the origin, the measurement and the estimation of the elements of the chosen transformer electric model. Then, to maximize the transferred power, we form a resonant structure by adding capacitors in parallel or in series with the transformer, then we develop a method to tune the whole. The comparison between the topologies leads us to choose a serial-serial compensation. Then we note that the technology chosen for capacitors, the static and dynamic insulation constraint can divide by more than two the power transmitted through a surface. Finally, we discuss how to rectify and regulate the output voltage without affecting the resonance or insulation provided, while minimizing the losses generated. A last part exhibit that with a suitable dissipation system and manufacturing process, it is possible to integrate the complete structure on silicon chips

O presente trabalho trata da análise da dinâmica de um pêndulo simples excitado em seu suporte por um mecanismo biela-manivela de forma ideal e não-ideal. No caso ideal, verifica-se que o resultado da excitação por este tipo de mecanismo se aproxima do resultado da excitação harmônica de suporte do pêndulo quando o raio da manivela é suficientemente pequeno em comparação com o comprimento da biela. A equação diferencial do sistema é resolvida numericamente e resultados do comportamento pendular são obtidos através de mapas de fase, histórico no tempo e seções de Poincaré. Expoentes de Lyapunov são, também, obtidos para a análise de casos caóticos posteriormente comparados com diagramas de bifurcação. Bacias de atração são desenhadas para os resultados estáveis do pêndulo: oscilatórios ou rotativos. Os resultados obtidos para a excitação por biela-manivela são dos mesmos tipos de movimento observados no caso do pêndulo excitado harmonicamente no suporte, entre eles: ponto fixo, oscilação, rotação pura, oscilação-rotação e o caos. Para a frequência de ressonância principal observam-se resultados caóticos em faixas mais largas de amplitude quando o raio de manivela se aproxima do comprimento da biela. Em frequências ressonantes menores nenhuma relação desse tipo pôde ser estabelecida. Uma análise utilizando o mesmo mecanismo é também feita com excitação por potência limitada de um motor elétrico linear de corrente contínua onde se investigou o efeito de feedback dado pelo pêndulo sobre o motor. Esses resultados são comparados com o caso ideal com a manivela acionada com rotação constante. Observa-se uma supressão do caos no caso não-ideal em casos de menor potência no motor. Entretanto, quando a potência de motor é maior, o modelo ideal coincide com o não-ideal. / In this analysis it was studied the dynamics of a simple pendulum excited by a crank-shaft-slider mechanism in the support ideally and non-ideally. In the ideal case, it was verified the result for an excitation by a crank-shaft-slider approaches to the result of the harmonically excited pendulum when the radius of the crank is sufficiently small in comparison with the length of the shaft. The resultant differential equation is solved numerically and the results of pendulum behavior are obtained by phase portraits, time histories and Poincaré sections. It is also calculated the Lyapunov exponents for the chaotic cases in analysis and a comparison is performed with bifurcation diagrams in the same regions. Basins of attractions are plotted for stable results like oscillatory and rotational solutions. In the results observed for the crank-shaft-slider excitation there are kinds of motion similar to those observed in the harmonic excitation: fixed points, oscillation, pure rotations, oscillation-rotations and chaos. However, in the principal resonance zone, chaotic results were more frequent when the radius of crank approaches the shaft length. A brief analysis is done concerning the same mechanism, but considering the excitation by limited power supply of a linear DC motor. In the sequence it is checked the feedback effect from the pendulum over the motor and comparison with the respective ideal excitation is accomplished where differences are commonly observed. With greater power the ideal model coincides with the nonideal model. In cases of lower power, the two models diverge in the results.