This thesis is performed in collaboration with Kraftpowercon AB in Surte, Sweden. Focus has been on to identify the powerlosses in one of Kraftpowercons halfbridge DC-DC converters. First theoretical calculations are made, the calculations is verified with measurements of six different operation modes. In a later stage, methods like soft switching and Synchronous rectifying are proposed to increase the efficiency for the converter. To achieve softswitching for the halfbridge, the LLC resonant converter topologies are implemented and examined.

Heat, clock scew and frequency optimization are some of the problems a semiconductor designer must face. By splitting a synchrounous block into multiple pieces which comunicates aSynchronously with eachother and provide them with independent clocks, these problems may be reduced. GALS (Global ASynchronous Local Synchronous) is a wrapper that wraps a Synchronous block and provides it with a clock. Multiple GALS-elements will make the whole system. The clockfrequency may be independently adjusted between each block.

This report describes a Synchronous machine model with magnetic saturation in d-axis, neutralconnection and electrical exciter interface for the transient simulator PSCAD/EMTDC. It hasbeen designed and verified in comparison to the regular machine model in EMTDC.The performance of the model is very good when incorporating a linear as well as a saturatedmagnetising inductance. The dynamic deviation is only thousandths to ten thousandths perunit. By using a cubic interpolation of the saturation curve, the model gives a good representationof the saturation effect. The open source code implementation of the Synchronousmachine model gives the possibility to easily adapt the model to specific requirements.The derived model makes it possible to simulate a Synchronous machine with its excitationsystems, e.g.

This report describes a Synchronous machine model with magnetic saturation in d-axis, neutralconnection and electrical exciter interface for the transient simulator PSCAD/EMTDC. It hasbeen designed and verified in comparison to the regular machine model in EMTDC.The performance of the model is very good when incorporating a linear as well as a saturatedmagnetising inductance. The dynamic deviation is only thousandths to ten thousandths perunit. By using a cubic interpolation of the saturation curve, the model gives a good representationof the saturation effect. The open source code implementation of the Synchronousmachine model gives the possibility to easily adapt the model to specific requirements.The derived model makes it possible to simulate a Synchronous machine with its excitationsystems, e.g.

This two years master?s thesis in Library and Information Sciences aims to investigate and put the services of 118100 Svar På Allt (SPA, an SMS mobile question and answer service) and Fråga biblioteket (FB, a library operated e-mail reference service) into the context of the reference encounter. Questions sent to SPA and their subsequent answers are analysed, and part of these questions are forwarded to FB for comparative studies. Both of the formats are compared to the reference encounter as a whole. The framing of the question originates in the assumption that there may be a need for further negotiation of the questions submitted to the aforementioned formats.

This master thesis has been performed at Vattenfall Power Consultant in Gothenburg and Trollhättan for Vattenfall Vattenkraft. In this report vacuum circuit breaker in small-scale hydropower stations with the rated power 4 MVA and below has been studied. Models of the stations are modeled and analyzed in PSCAD/EMTDC to study the high voltage transients that are created after current chopping with vacuum circuit breaker. Vacuum circuit breaker may chop the current before it reaches zero value, which means that high voltage transients can be created. The equipment of the stations can be destroyed by high voltage transients.The purpose of this thesis is to examine the use of vacuum circuit breaker in small-scale hydropower stations and the risk for high voltage transients from current chopping.According to the results there is a risk of high voltage transients after current chopping with small Synchronous generators in stations with the operating voltages 0.4 kV and 3.6 kV.

This two years master?s thesis in Library and Information Sciences aims to investigate and put the services of 118100 Svar På Allt (SPA, an SMS mobile question and answer service) and Fråga biblioteket (FB, a library operated e-mail reference service) into the context of the reference encounter. Questions sent to SPA and their subsequent answers are analysed, and part of these questions are forwarded to FB for comparative studies. Both of the formats are compared to the reference encounter as a whole. The framing of the question originates in the assumption that there may be a need for further negotiation of the questions submitted to the aforementioned formats.

The interest for power and energy measurement has greatly raised with todays increasing electricity prices and enviromental awareness. In the search for energy efficient solutions, the measurements are more complex due to increasing of non linear components. Harmonics and non sinusoidal voltages put high demands on sampling and filtering. Meanwhile, the price must be controlled so the customer still will find it interesting to invest in smaller plants. ITT W&WW asks for a robust, heat resistant power meter with compact dimensions to allow mounting inside the casing of a pump.

This master thesis is one part of a project, called ?StabSim?, with the purpose to develop a simulation model for the align and stabilisation system in main battle tank 122. The origin of this project is that it should be possible to make control analysis without risking any hardware. Besides that it will be easy to change components in order to investigate the behaviour of the system. The report includes modelling of tower and weapon mechanics and also the modelling of the Synchronous motors, which control these.

Vid implementeringar av FIFO-arkitekturer har asynkrona FIFO-konstruktioner använts. Denna lösningsmetod har visat sig innehålla en del brister vid tillämpning på höghastighets system, vilket ledde till att synkrona FIFOn började ersätta asynkrona FIFOn. Den synkrona arkitekturen har samma funktonalitet som de asynkrona typerna med fördelar som högre hastighet och enklare gränssnitt. I rapporten har olika FIFO-konstruktioner behandlats och jämförelser har gjorts mellan synkrona och asynkrona arkitekturer. Det vid ISY konstruerade SRAM-minnet har sedan avgjort vilken typ av FIFO-arkitektur som varit bäst lämpad för implementering.

At the Division of Electricity at Uppsala University there is an experimental rig forhydroelectric generators. The experimental rig?s vital part is a 12-pole Synchronousmachine, whose electrical characterizing parameters (resistances, inductances andtime constants) are unknown. The aim of this thesis is to characterize the machine inits current state by perform a Standstill Frequency Response (SSFR) test. From theanalysis of the measurement data, which is a part of the test, a set of basic parametershave been received.

A design methodology to mitigate timing problems due to long wire delays is proposed. The timing problems are taking care of at architecture level instead of layout level in this design method so that no change is needed when the whole design goes to backend design. Hence design iterations are avoided by using this design methodology. The proposed design method is based on STARI architecture, and a novel initialization mechanism is proposed in this paper. Low frequency global clock is used to synchronize the communication and PLLs are used to provide high frequency working clocks.

Dysfunction of the upper respiratory tract is a common cause of impaired performance and intolerance to exercise in racehorses and include several upper airway obstructions. The ones termed dynamic obstructions are primarily seen during physical exertion and affected horses often appear to be normal during endoscope examination at rest. The correlation between diagnoses made at rest respectively exercise is low, suggesting that an examination at rest alone is likely to be insufficient. The upper respiratory tract is exposed to great differences in pressure throughout the respiratory cycle; variations that are further altered during strenuous exercise and affect the rigidity of upper airway structures. In presence of great fluctuations in pressure, stability is achieved through coordinated and Synchronous neuromuscular mechanisms. Due to nerve damage or anatomical abnormalities, these functions may be disrupted and further cause a dynamic collapse of the upper respiratory tract when pressure changes become too severe. The etiology behind the neuromuscular dysfunction is not yet fully understood.

The climate affects animal populations through several processes. These processes includereproduction, phenology and the success of hunting. By influencing the phenology of species theclimate also affects the way species interact. If a climate-induced phenology change promotes abasal species to bud earlier in the spring for example, this will affect the links to other species inthe food web due to a time lag in the tropic levels above. This dependence, that a predator has tobeing Synchronous to its prey, is called the match/mismatch hypothesis (MMH).

The use of spread spectrum signals has increased dramatically in military applications. Finding methods for detecting and positioning of these signals have become interesting research areas for signal intelligence purposes. One method is to measure the time difference of arrival (TDOA) that occurs when two receivers are Synchronous and spatially separated. Based on the TDOA-technique an audio-demonstrator has been developed and implemented. This report describes the theory for how sound received in microphones can be used to extract information about the transmitter?s position from the measured time difference.