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.

The purpose of this thesis was to examine if there where fallacies in the design solutions for the business system IFS Applications from a user perspective, and if so, correct these from a cognitive science approach.Data collection consisted of three main portions. These where; workshop, individual interviews and observations. The collected data was analyzed and resulted in identification of two main areas in the application that where found lacking.The result of the study showed that the usability for processing large amounts of data and the lack of customization where the main flaws in the application. Two low fidelity prototypes where created with the purpose of rectifying the underlying flawed design solutions that where identified from the collected data..

The purpose of this thesis was to examine if there where fallacies in the design solutions for the business system IFS Applications from a user perspective, and if so, correct these from a cognitive science approach.Data collection consisted of three main portions. These where; workshop, individual interviews and observations. The collected data was analyzed and resulted in identification of two main areas in the application that where found lacking.The result of the study showed that the usability for processing large amounts of data and the lack of customization where the main flaws in the application. Two low fidelity prototypes where created with the purpose of rectifying the underlying flawed design solutions that where identified from the collected data..

The purpose of this thesis was to ease the implement of an upcoming intranet for a target group who had used the previous system to an unwanted low extent. After qualitative and quantitative studies I found that the users of the current intranet thought it was hard to navigate and did not understand neither the relevance of it in their own work nor knew which information it contained.Since I did not have access to the new system by the time of the making of this thesis I concentrated on rectifying possible problems with the new system regarding the relevance and the contained information. With basis in a number of theories I produced an information brochure, whose object was to inform about the content and to convince the target group of the relevance and utility of the new intranet. .

The purpose of this degree project was to build laboratory equipment for a new course in power electronics that starts this autumn 2010 at Uppsala University. The equipment is intended for student labs and it covers the most important areas of the course including rectifying, buck-/boost-converters and PWM-modulation. It is built as one sealed unit where all the electronics are built-in but visible and it has a connection board where students safely can connect the different circuits. The project has advanced from theoretical studies of circuit design, choosing of components and simulations to drawing the printed circuit board (PCB), soldering, case building, final testing and troubleshooting - basically most steps from an early idea to a final product. Measurements on the final product gave about the same results as the earlier simulations of the circuits and the result is overall satisfying..