In the telecom industry, one-phase rectifiers are commonly used in base stations and site power systems. The abundant of this one phase loads connected to the three-phase network where three-phase installations are required can enhance the amount of unbalances in the three-phase systems. Unbalanced systems can cause the three-phase connections to be out of the norm, i.e. it can be out of the requirements of the distribution company or installation standards and thus shall not be allowed to be connected to the network. Additionally, unbalance can cause problems in terms of energy loss in kWh, greenhouse emissions, which can also impose specific standards and guidelines for three-phase electricity users and manufacturers. Those problems are addressed in the literature. This thesis investigates the requirements and standards for phase balancing in three-phase installations and uncovers solutions to mitigate these unbalances in the perspective of the telecom industry. Through market investigation, the knowledge and solutions to this day have been found and summarized, which is then used to further dig into the technical understanding of phase balancing techniques. The investigation shows that there is only a small market that requests and has standards for phase balancing of loads. The different solutions evaluated and modelled shows they can mitigate the load balancing issue in three-phase installation likey to a specific limit according to required standards.

This thesis studies a method of measuring ion mobility in insulation liquids for transformers (transformer oil). This method works by using a square wave voltage to make the charged particles (space charge) inside the oil move between two electrodes. By measuring and analysing the resulting current, the ion mobility of the oil can be calculated with an equation derived from the ion drift diffusion model. In order to study this method, different aspects of the technique were tried. Four different oils were involved, their measured ion mobility is presented at the end. Two different electrode materials were tried and the effects of measuring with different voltages and different frequencies were documented. At the end it was concluded that in order to get a good measurement using this method, it requires the right combination of voltage and frequency. These parameters are dictated mainly by the oils resistivity and the distance between the electrodes.

This study was conducted as to attempt to find whether a three-camera setup could improve depth map retrieval as opposed to a two-camera setup. The study is based on three main ideas to exploit information from the additional camera. These are three cameras on one axis, as to exploit wide and short baseline benefits, three cameras on different axes, as to exploit vertical and horizontal scanning of the scene and a third idea of combining the two previous ideas. More than three cameras would impose particular implications on the solution and without sufficient theoretical justification thereof the study was limited to a study of the different three-camera configurations possible. As a practical connection was of interest, the study was further limited by the possibility to perform in real-time. An implementation based on previous research was made such as to evaluate images with specific scenes. Pre-processing by Census transformation of the images, camera calibration and rectification of different camera setups and optimizaton by the SGM algorithm are part of the solution used to retrieve results to analyse. Two tests were then studied, first one with rendered images and then one with images from real cameras. From these tests it was noted that a three-camera configuration can improve upon the results significantly and further, if the third camera was placed in perpendicular axis to the first camera pair, unique information was yielded which improves upon the result in specific cases. Using three cameras on the same axis showed no improvement when considering the error metrics BMP and BMPRE, but offers wider application uses, consistently providing better results than the worst pair.

Heavy metal contamination in environmental applications is particularly important because of its potential impact on associated ecosystems and human health. At present, monitoring of heavy metals is usually done by taking and preparing samples for off-line laboratory measurements. X-ray fluorescence (XRF) analysis is a powerful and widely used tool for determining the elemental composition and concentration of chemical species in materials. This project is a feasibility study for the possibility of on-line XRF systems for continuousand direct analysis of industrial processes and environmental emissions. The feasibility of such measurements depends on the accuracy with which the concentration can be measured within a given response time. Therefore, this project is focused on investigating possible background suppression of the XRF spectrum. First, an XRF setup has been built, and its capability has been compared to a commercial scanning electron microscope with energy dispersive spectroscopy (SEM-EDS). The qualitative analysis and semi-quantitative analysis of heavy metal contamination in fly ash was performed and compared. Due to minimal sample preparation, the developed XRF system is suitable for in-situ measurements. A series of experiments was performed to optimize the signal-to-noise ratio of the spectra achieved from chromium contaminated liquid samples. The most significant factor turned out to be the primary X-ray source filter. Numerical simulation models have been developed in the Monte Carlo N-particle radiation transport code (MCNP), to calculate the X-ray fluorescence intensities and the detection limit for chromium in liquid samples. The experimental results agree with the results predicted by the simulation model, hence the model is used for optimization of the XRF system. Further, XRF mapping of chemical element distributions on a microscopic level has been obtained by using both X-ray scanning microscopy and full-field projection microscopy. The resultingdata from these microscopy measurements can guide further comprehensive environmental and industrial monitoring missions by providing additional spatial distribution information. In conclusion, the first research contribution presented in this thesis is the demonstration of the possibility to perform in-situ XRF measurements of chromium contamination in leachate with a limit of detection below the legal environmental limits. The second is the demonstration of XRF mapping on amicroscopy level, where a polycapillary X-ray optics setup achieves a similar intensity as a geometrically corresponding pinhole optics setup. / <p>Vid tidpunkten för framläggningen av avhandlingen var följande delarbeten opublicerade: delarbete 2 (inskickat), delarbete 3 (accepterat), delarbete 4 (accepterat).</p><p>At the time of the defence the following papers were unpublished: paper 2 (submitted), paper 3 (accepted), paper 4 (accepted).</p>

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Denna rapport utreder på uppdrag av Norrmontage AB hur kostnader som orsakas av belastningsförluster(Pb) och tomgångsförluster(Po) för en transformator som är ansluten till en fjällby vilket har en ganska extrem skillnad mellan effektuttag vid hög och lågsäsong. Det befintliga transformatorn är märkt 800kVA 22/0,420kV. En teori från Norrmontage AB är att installera ytterligare en transformator som har lägre tomgångsförluster(P0) och belastningsförluster(Pb) jämfört med befintliga transformatorn och att en skiftning mellan dessa kommer att ske beroende på effektuttaget. Mätdata innehåller effektuttag från den befintliga 800kVA transformatorn under perioden 2013-11-14 och 2016-02-29 för dygnets alla timmar. En utredning på mätdata via Excels stapeldiagram ger som resultat att effekt uttaget är väldig lite under perioden 4 april och 31 oktober(Lågsäsong). Det finns också mindre effektuttag under vissa dagar utöver lågsäsongen. Men förstahand har det tagits hänsyn till förhållandena under lågsäsong. De transformatorer som är kandidater för det mindre effektuttag under lågsäsong är CTS 315kVA 22/0,42kV och CTS 500kVA 22/0,42kV vilket båda har betydligt lägre tomgångsförluster(P0) och belastningsförluster(Pb) än den befintliga transformatorn. Investeringskalkylen använder pay-off modellen och denna rapport påvisar att det inte är lönsamt att investera i att installera någon av de kandiderade transformatorer parallellt till den befintliga transformatorn. Tekniklösning har varit utmaning på detta projekt, vilken gjordes åtanke att säkra avbrottfri elleverans till konsumenterna.

With more Electric vehicles (EV) on the street, it will lead to an impact of the electric grid. In this work, the charging process of an EV the high-frequency harmonics will be analysed. A common problem with EV charging is that the AC DC converter produces highfrequency harmonics, which can lead to function loss for electronics at home or reduce the lifetime. Today's environmental goal of reducing CO2 emissions from transport has led to more and more fossil-free cars starting to roll on the road. With more and more battery-powered electric cars on the roads and sales of electric cars pointing up, more and more questions are raised about how electric car charging affects the electric grid and above all how it will affect surrounding equipment that is close or on the same node when electric cars are being charged. This thesis will have a deeper look into the high fervency’s harmonics during charging. The range of interest is 2 kHz and 200kHz. The reason for choosing the range is that there has been a new IES6100 standard that includes harmonics in the range of 2 kHz to 200 kHz. The measurement method was done by measuring a normal Dummy load, the charge box by itself, 2 different cars and with the 2 cars together. 1 car had only the option to charge at 3,7 kWh on one phase and the second car was charge with 11 kWh on 3 phases. Measurement points where the voltage between Phase and Ground together with Neutral and Ground. The current was measured on one Phase and Neutral. The reason to have the ground as a referencing point is to see how much of a voltage the Neutral will get during charging. Due to lack of time and lack of ICE standard combined with the Covid19 situation measurements have been done manually and only on 2 different types of EV’s and during different battery levels. But this thesis has a good base for future evaluations of high frequency’s harmonic analyses of different Electric vehicles. The results of the measurements have been reported in a different section. Together with the spectrum diagram and Diagram of the number of the individual harmonics.

In this present world, there is a huge requirement of portable devices for that the analysis of low-dropout or LDO regulators have been on high priority. So, for every respective device, there is a power budget that acts as the main constraint to design an LDO. The LDO design aims to suppress the noise and supply noise-free or low noise output. This thesis paper illustrates several designs of output capacitor-less LDO architecture to enhance Power Supply Rejection (PSR) and optimization of the ideas from different literature to achieve the low quiescent current, stability with fast transient response while the input voltage is low over a wide range of load current. Differ-ent types of transistor schematic designs under definite specifications of the LDOs, which are mostly integrated by major components like Error Amplifier (EA) and pass transistor, feedback resistors, and relatively small output capacitor have mostly considered for the designs. However, some buffer attenuation techniques which can improve the PSR have also been shown with a proper diagram. The design of LDOwith the components and how to design the pass device and their trade off’s have been has been discussed. Different techniques of PSR enhancement among which some of the techniques have been implemented have been illustrated with respective diagrams. A study of executed techniques under the specifications with comparative results has been shown with their trade-off with the other architecture. The contribution is an LDO that has been simulated in Cadence specter and designed in CMOS FinFET process node atVdd= 0.95 V with a load current of 50 mA -75 mA and an output voltage of 0.75 V with a small output capacitor of 200 pF, a PSR of−25 dB at 100 MHz has been achieved whereas the current consumption at the load is 245μA, while meeting the targeted stability analysis of gain margin and phase margin of 47 dB and 63◦respectively. A small voltage droop of 36. 6mV for rising edge and−15.99 mV for falling edge over a 100μA to 75 mA step-change in10 ns has been observed. / I dagens värld finns det stora behov av bärbara enheter och krav på analys avregulatorer (LDO). För varje typ av enhet finns det en energibudget som fungerarsom huvudsaklig begränsning för att utforma en LDO. LDO-konstruktion syftar tillatt leverera brusfri eller lågbrusig utspänning. Detta examensarbete visar på flerakonstruktioner av utgångskondensatorfria LDO-arkitekturer för att förbättra PowerSupply Rejection (PSR). Optimering av idéer från olika litteraturkällor görs för attuppnå låg viloström och stabilitet med snabb respons med låg ingångsspänning överett brett intervall av lastström. Olika typer av konstruktioner schemanivå för precisa LDO-specifikationer, mestadelsintegrerade med de viktigaste komponenter såsom felförstärkare (Error Amplifier,EA) och passtransistor, återkopplingsmotstånd och relativt små utgångskonden-satorer, har studerats. Buffertdämpningstekniker som kan förbättra PSR har ocksåinkluderats. Konstruktion av LDO:er på komponentnivå och man utformar pass-enheten och dess kompromisser diskuteras också. Implementering av några olikatekniker för PSR-förbättring illustreras med schema. En studie av utförda teknikerenligt specifikationerna med jämförande resultat ingår också. Resultat är en LDO som har simulerats i Cadence Spectre i en CMOS FinFETprocess med en matningsspänning på 0,95 V, en belastningsström på 50 mA - 75mA, en utspänning på 0,75 V och med en liten utgångskondensator på 200 pF. PSRpå−25 dB vid 100 MHz har uppnåtts medan strömförbrukningen vid belastningenär 245μA, samtidigt som kraven på marginal för förstärkning på 47 dB och fas 63°har uppnåtts.  Ett litet spänningsfall på 36,6 mV för stigande signal och−15,99 mV för fallande signal under en förändring från 100 μA till 75 mA på 10 ns harobserverats. / <p>ISY </p>

There is a need for increasing speed on external links and harmonics are often seen and are a challenge to master. Especially for products within the space industry where the requirements are narrower due to the harsh environment it needs to withstand. This thesis is investigating a potential leakage path around the interface from the board to harness through Spacewire connectors. This leakage is seen as radiated emission and the focus of this thesis is to see if there is a possibility to decrease these emissions by minimising the ground loop that is potentially causing these issues in the UHF- and S-band. In order to verify that the proposed solution a reverberation chamber was used to analyse the performance of the solution when a twisted cord attached to a ground plane and wrapped around the harness was used to minimise the dierence in potential between the interface of the board to harness. The results showed that the proposed solution was inconclusive, but another discovery was made, it was found that the radiated emissions seen in the S-band can be decreased signicantly by improving the contact between the connector and the frame. This could be done with a beryllium-copper gasket. A decrease could also be seen in the UHF-band but not as substantial as the S-band.

With the growing software technologies companies tend to develop automated solutions to save time and money. Automated solutions have seen tremendous growth in the software industry and have benefited from extensive machine learning research. Although extensive research has been done in the area of automated bug classification, with the new data being collected, more precise methods are yet to be developed. An automated bug classifier will process the content of the bug report and assign it to the person or department that would fix the problem. A bug report typically contains an unstructured text field where the problem is described in detail. A lot of research regarding information extraction from such text fields has been done. This thesis uses a topic modeling technique, Latent Dirichlet Allocation (LDA), and a numerical statistic Term Frequency - Inverse Document Frequency (TF-IDF), to generate two different features from the unstructured text fields of the bug report. A third set of features was created by concatenating the TF-IDF and the LDA features. The class distribution of the data used in this thesis changes over time. To explore if time has an impact on the prediction, the age of the bug report was introduced as a feature. The importance of this feature, when used along with the LDA and TF-IDF features, was also explored in this thesis. These generated feature vectors were used as predictors to train three different classification models; multinomial logistic regression, dense neural networks, and DO-probit. The prediction of the classifiers, for the correct department to handle a bug, was evaluated on the accuracy and the F1-score of the prediction. For comparison, the predictions from a Support Vector Machine (SVM) using a linear kernel was treated as the baseline. The best results for the multinomial logistic regression and the dense neural networks classifiers were obtained when the TF-IDF features of the bug reports were used as predictors. Among the three classifiers trained the dense neural network had the best performance, though the classifier was not able to perform better than the SVM baseline. Using age as a feature did not give a significant improvement in the predictive performance of the classifiers, but was able to identify some interesting patterns in the data. Further research on other ways of using the age of the bug reports could be promising.