This thesis deals with the issue of switching power supply in terms of noise ratios in the output voltage. In the theoretical part analyzes the basic principle of classical and resonant topology switching power converters in terms of output voltage ripple and switching noise. There are also some possibilities of compensation to minimize switching noise and output ripple. The second part describes the custom design a low noise switching power supply, which is composed of an active power factor corrector, power converters and ripple limiter. The main power converter is designed as an LLC resonant converter. The last part deals with the actual construction of the proposed source, its measurement and presentation of the results.

The work generally deals with the possibilities of preparing hot water in household and analyzes saving posibilities. At the beginning of work the history of hot water preparation is briefly indicated. Chapter 3 deals with different ways of heating. Described in more detail electric storage heating is in chapter 4, where can be found the effect of heating to the power network, especially to the daily load diagram. The following are the information of the tariff policy, as a tool for motivation of consumers, for using the storage heating. In the next part, beginning with the fifth chapter, is written about the possibility of energy saving by means of intelligently controlled boiler. That eliminates the disadvantage of storage heating, which are the tank thermal losses. Heating is based on a certain regularity in the behaviour of the user and manages the preparation of water according to expected consumption. The sixth chapter then contains design of own algorithm for economical control of heating and also energetic and economic assessment of potential savings.

This thesis deals with analysis and implementation of Power-HIL system that is designed to simulate real DC motor with comutator and permanent magnets. For problem analysis were used simulations of real components in Matlab / Simulink. The electronic parts of system were simulated with using the SimElectronic library. Idividual hardware components were designed according to simulation results. The outcome of this thesis is a power electronic simulator of real DC motor, which is implemented on dSPACE platform. The system allows software to setup parameters and behavior of simulated motor. The final system can be used for testing DC motor ECU (electronic control units).

The aim of this thesis is to determine the size of overshoot produced at the output of a linear continuous second order system controlled by pulse width modulation depending on the period and duty cycle of the modulation and system parameters. This thesis contains analytic calculation of the size of overshoot produced at the output of the second order system with damping ratio > 0, except the damping ratio equals to 1 (i.e. both underdamped and damped system) depending on period and duty cycle of the modulation. This thesis also includes a comparison of partial analytic results to numerical simulation in Matlab program and also with measurement at second order system model.

In der Arbeit wird das Reibungsverhalten an Polymerbürsten im nanoskopischen und makroskopischen Kontakt beschrieben. Besonderes Augenmerk liegt auf den durch Reibung hervorgerufenen Deformationen.

The displacement of the variable displacement pumps can be adjusted by changing the swivel angle of the swash plate. In fact, the swivel angle oscillates because of the oscillating torque on the swash plate, which caused by the pressure fluctuation of the piston chamber. The swivel angle is most often considered as a constant value in previous studies. However, the oscillation of the swash plate leads to an additional movement of the piston, which has an impact on the pressure fluctuation and the flow ripple. In this study, an improved model of a self-supplied variable displacement pump is established. The swash plate oscillation under different operating conditions is presented. In order to investigate the effect of the swash plate oscillation on the pressure ripple, a comparison between the case of the fixed swash plate and the oscillated swash plate is conducted. Results show the pressure ripple with an oscillated swash plate shows a smaller pressure ripple. It also shows that the nine pistons and the control mechanism both affect the pressure ripple and flow fluctuation.

This paper builds on the study Prices on the Second-hand Market for Swedish Family Housesconducted by Lennart Berg, economist and associate professor emeritus from UppsalaUniversity in 2002. This study attempts to identify inter-and intraregional pricedependencies in Sweden for the second hand market for family houses. The house priceindices used in this econometric analysis commences in 1990:1 and ends in 2018:4 for allregions in accordance to NUTS 2 in Sweden.This thesis models the change of the regional prices for one-and two family houses indicatingthat the metropolitan area of Stockholm contributes predominantly to all other regionsthroughout the country. In addition, the capital city also shows cointegrated relationshipswith all regions although not the contrary. Shocks to the housing market of Stockholmindicate that Gothenburg, the Western region and Malmö are affected contemporaneouslyfollowed by the other regions nationwide with a certain time lag leading to say that thecontribution and influence of the capital city´s house price development leads the pricedevelopment throughout the country, Sweden. / Detta examensarbete ligger till grund av den tidigare studien Prices on the Second-handMarket for Swedish Family Houses av Lennart Berg, nationalekonom och professor emerituspå Uppsala Universitet, 2002. Denna studie har som mål att finna de inter-och intraregionala pris förhållanden i Sverige på den inhemska andrahandsmarknaden för en-och tvåfamiljhus. Med hjälp av ekonometriska analyser har fastighetsprisindex använts i rapportenmellan år 1990:1 till 2018:4 för samtliga regioner i landet enligt indelning av NUTS 2.Denna uppsats skattar de regionala prisförändringar för en-och två familjehus därindikationer tyder på att Stockholms län verkar vara prisledande i relation till alla andraregioner och storstadsområden i Sverige. Därutöver, visar det sig att huvudstaden harkointegrerande samband med resten av landets regioner dock ej tvärtom. Simuleradeekonomiska chocker på Stockholms län visar att att Stor-Göteborg, Västsverige och Stor-Malmö är påverkade samtidigt med hänsyn till tid följd av de resterande regionerna med ettvisst lag. Detta kan tyda på att Stockholms regionala utveckling samt prispåverkan lederprisutvecklingen i landet.

Sjöfarten är idag dominerad av förbränningsmotorer som är beroende av fossila drivmedel. Elektrifiering är en av huvudstrategierna för att möjliggöra fossilfri energiförsörjning inom internationell sjöfart. Polymerelektrolytbränslecellen (PEMFC) omvandlar vätgas till elektricitet med hög verkningsgrad och är för närvarande kommersiellt tillgängligt upp till MW-skala för ett fartyg. Vätgas är en utmärkt energibärare för att tillgodose hög energidensitet hos ett fraktfartyg. Rippelströmmar från elkraftskomponenter påstås accelerera åldring av materialen i PEMFC och kan därför skapa negativa effekter över tid som påverkar livslängden av systemet.  De tillgängliga studier som utvärderar rippelströmmars påverkan på åldring i PEMFC är begränsade. Resultaten i dessa studier är tvetydiga och saknar tydliga kopplingar mellan rippelströmmarnas inverkan på åldringsfenomen, som på sikt kan påverka den tekniska livslängden. Målet med examensarbetet var att identifiera effekten av rippelströmmar på åldring av bränslecellen vid typiska körförhållanden för ett fraktfartyg. Tester genomfördes på en PEMFC genom att applicera en sinusformad (70 Hz, 50 % amplitud) rippelström på en dynamisk last som simulerar ett fraktfartyg. En konstant lastcykling vid 0.4 A/cm2 utfördes som ett komplement för att verifiera den dynamiska lastens inverkan på bränslecellen.  Alla tester resulterade i prestandaförluster både under den konstanta och dynamiska lasten, med eller utan rippelström. Men resultaten indikerade att effekten av en sinusformad rippelström inte orsakade någon signifikant åldring varken vid konstant respektive dynamisk lastcykel. / The marine shipping industry is dominated by fossil fuel driven propulsion. Electrification of marine vessels is one of the main strategies to enable emission-free propulsion. Hydrogen is an excellent energy carrier to meet the power demand of a marine vessel. Proton exchange membrane fuel cells (PEMFC) is a commercially available alternative for converting hydrogen into electricity. However, durability issues of the PEMFC is a constraint with the technology which limits technical lifetime. Research around ripple currents impact on degradation of PEMFC is scarce and the reported results are ambiguous and lack clear correlation between the effects of the ripple current on the lifetime of a PEMFC. This master thesis evaluates the impact on degradation of a single cell PEMFC by imposing a sinusoidal (70 Hz, 50 % amplitude) AC ripple to a dynamic load cycle. The dynamic load cycle is designed to simulate typical operating conditions of a marine vessel. Constant load cycling at 0.4 A/cm2 with the same ripple characteristics was also conducted to verify the dynamic load cycling impact on the performance losses of the PEMFC. The in-situ characterization showed performance losses both during the dynamic and constant load cycling, for the ripple current and reference tests. To conclude, no significant effects on degradation by the sinusoidal ripple current of 70 Hz and 50% amplitude is found when applied to a single cell PEMFC despite of performance losses for all cases.

Light detection and ranging (lidar) is used for various applications such as remote sensing, altimetry and imaging. In this talk, a linearly chirped pulse source is introduced that generates wavelength-swept pulses exhibiting ~6 nm optical bandwidth with > 20 km coherence length. The chirped pulses are used in an interferometric lidar setup to perform distance measurements with sub-millimeter resolution (using pulses that are a few meters long), at target distances > 10 km, with at least 25 dB signal-to-noise ratio at the receiver. A pulse repetition rate of 20 MHz provides fast update rates, while chirped pulse amplification allows easy amplification of optical signals to high power levels that are required for long range operation. A pulse tagging scheme based on phase modulation is used to demonstrate unambiguous, long range measurements. In addition to this, simultaneous measurement of target range and Doppler velocity is performed using a target moving at a speed of over 330 km/h (205 mph) inside the laboratory. In addition to this, spectral phase modulation of the chirped pulses is demonstrated to compensate for the undesirable ripple in the group delay of the chirped pulses. Moreover, spectral amplitude modulation is used to generate pulses with Gaussian temporal intensity profiles and a two-fold increase in the lidar range resolution (284 um) is observed.

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