Search for dissertations about: "Electrical engineering"

Showing result 6 - 10 of 5845 swedish dissertations containing the words Electrical engineering.

  2. 6. Component and system design of a mild hybrid 48 V powertrain for a light vehicle

    Author : Stefan Skoog; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Extra low voltage; Hybrid Electric Vehicle; 48 V; Li-ion battery; Calorimetric measurement; Oil cooling; Efficiency; Multi-phase; MOSFET; Power Electronics; Permanent Magnet Synchronous Machine; PWM; Inverter; Power density;

    Abstract : This thesis presents contributions in three areas relevant for the development of 48 V mild hybrid electric powertrains for cars. The first part comprises methodologies and extensive testing of lithium-ion battery cells in order to establish the electric and thermal performance using equivalent circuit models. READ MORE

  4. 7. Secure GNSS-based Positioning and Timing : Distance-Decreasing attacks, fault detection and exclusion, and attack detection with the help of opportunistic signals

    Author : Kewei Zhang; Panagiotis Papadimitratos; Erik G. Larsson; Christina Pöpper; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

    Abstract : With trillions of devices connected in large scale systems in a wired or wireless manner, positioning and synchronization become vital. Global Navigation Satellite System (GNSS) is the first choice to provide global coverage for positioning and synchronization services. READ MORE

  5. 8. Prediction horizon requirement  in control and extreme load analyses for survivability : Advancements to improve the performance of wave energy technologies

    Author : Zahra Shahroozi; Jens Engström; Malin Göteman; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; control; optimal velocity; non-causality; maximum power output; extreme waves; wave tank experiment; end-stop compression; wave breaking slamming; PTO damping; return level; return period; peak-over-threshold;

    Abstract : The main objective of wave energy converters (WECs) is to ensure reliable electricity production at a competitive cost. Two challenges to achieving this are ensuring an efficient energy conversion and offshore survivability. READ MORE

  6. 9. Thermal insulation of the combustion chamber in a light duty diesel engine

    Author : Joop Somhorst; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; temperature swing; crevice effect.; porosity; heat transfer; surface roughness; efficiency; diesel engine; surface sealing; thermal barrier coating;

    Abstract : Reduction of heat loss from the combustion chamber in an engine has great potential to decrease fuel consumption and CO2 emissions. Research on thermal barrier coatings (TBC) has been performed since the early eighties to address this potential. READ MORE

  7. 10. Detection of Partial Discharges at Fast Rising Voltages

    Author : Thomas Hammarström; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Partial discharges; cavities; repetitive voltages; high dV dt.; square like voltages; short rise time; measurements;

    Abstract : The present demand for higher efficiency and flexibility in the energy sector has ledto an increased use of power electronic generated waveforms as these allow energyconversion between different frequencies including DC. The generated waveformsare usually synthesized by so called Pulse Width Modulation (PWM) techniques,where the desired waveform is approximated by a number of square shaped pulseswith a short rise time. READ MORE