Sökning: "electric conduction"

Visar resultat 1 - 5 av 43 avhandlingar innehållade orden electric conduction.

  1. 1. Modular Battery Systems for Electric Vehicles based on Multilevel Inverter Topologies - Opportunities and Challenges

    Författare :Anton Kersten; Chalmers tekniska högskola; []
    Nyckelord :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; Dynamic reconfiguration; Energy storage; Energy efficiency; Drive cycle efficiency; Power MOSFET; vehicles; H-bridge; Multilevel systems; Electromagnetic compatibility; Modular battery systems; Battery system performance; Modular multilevel converters; Conduction losses; Electric vehicles; Batteries; Dual battery pack; Cascaded converters; DC-AC power converters; BMS; Common mode noise; Battery modeling; vehicle electrification;

    Sammanfattning : Modular battery systems based on multilevel inverter (MLI) topologies can possibly overcome some shortcomings of two-level inverters when used for vehicle propulsion. The results presented in this thesis aim to point out the advantages and disadvantages, as well as the technical challenges, of modular vehicle battery systems based on MLIs in comparison to a conventional, two-level IGBT inverter drivetrain. LÄS MER

  3. 2. Surface potential dynamics on insulating polymers for HVDC applications

    Författare :Shahid Alam; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric spectroscopy; silicone rubber; intrinsic conduction; surface potential decay; activation energy; electric conductivity; HVDC insulation;

    Sammanfattning : The use of high voltage direct current (HVDC) technology in power transmission systems is continuously expanding. Nowadays, HVDC transmissions operate at voltages up to 800 kV and higher levels are being developed. LÄS MER

  4. 3. Dielectric Properties of Liquid-Impregnated Porous Solids

    Författare :Bo Nettelblad; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fluid-solid interface; porous microstructure; temperature; ion-containing liquid; transport properties of porous media; brine; salinity; electric conduction; models of composite media; interface phenomena; dielectric relaxation; rock;

    Sammanfattning : Dielectric spectroscopy is a versatile tool that can often be used as a non-destructive, indirect way of measuring other important properties (such as content of crude oil or degree of curing of a resin). The dielectric properties of materials are thus of interest in several circumstances and not only for materials used for electrical purposes (such as electrical insulation). LÄS MER

  5. 4. Studium av de dielektriska egenskaperna hos impregnerade porösa material

    Författare :Bo Nettelblad; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fluid permeability; interface phenomena; brine; dielectric relaxation; permittivity; rock; fluid-solid interface; transport properties of porous media; electric conduction; grain size distribution;

    Sammanfattning : .... LÄS MER

  7. 5. Point defects and ion conduction in solid oxides: a first-principles case study of La2Zr2O7

    Författare :Joakim Nyman; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; proton; self compensation; hydrogen economy; DFT; La2Zr2O7; acceptor doping; lanthanum zirconate; oxygen vacancy; SOFC; pyrochlore; point defect; trapping; computational methods; solid oxide; charge compensation; first principles; ion conduction; solid oxide fuel cell; ceramic electrolyte; defect cluster; fuel cell; hydrogen;

    Sammanfattning : In the endeavor to attain a clean environment and sustainable energy consumption, the notion of a future hydrogen economy stands out as one of the grandest visions. Striving for this vision, a critical task lies in optimizing the performance of the fuel-cell devices responsible for extracting electric power from the energy stored in hydrogen molecules. LÄS MER