Sökning: "Energy Modulation"

Visar resultat 1 - 5 av 218 avhandlingar innehållade orden Energy Modulation.

  1. 1. Modulation, efficiency and lifetime of two-level and multilevel converters for a hydropower application

    Författare :Chengjun Tang; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Pumped-storage hydropower; pulse width modulation; losses; modular multilevel converter; efficiency; variable speed; converter; lifetime; space vector modulation; thermal modelling; neutral point clamped converter;

    Sammanfattning : Along with the integration of the renewable energy in the electrical grid, the pumped-storage hydropower has gained more and more attention due to its fast response and energy storage ability. To have a higher overall efficiency and more flexibility of the system, variable speed is preferred in the operation of the pumped-storage hydropower applications. LÄS MER

  3. 2. 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

  4. 3. First Principles Modelling of Clean Energy Materials

    Författare :Pjotrs Žguns; Natalia Skorodumova; Andrei Ruban; Susanne Mirbt; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DFT; energy; catalysis; ionic conductors; SOFC; adatom charging; anharmonicity; configurational energy; Materials Science and Engineering; Teknisk materialvetenskap;

    Sammanfattning : This licentiate thesis presents the density functional theory study on clean energy materials relevant for catalysis applications, and for solid oxide fuel cells.In the first part of the thesis the metal supported ultrathin films, namely ScN/Mo, MgO/Mo and NaF/Mo are considered, and the Cu atom adsorption and charging on them is explored. LÄS MER

  5. 4. Using Low Energy Light to Enable High Energy Photochemistry

    Författare :Wera Larsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; triplet-triplet annihilation; solar energy conversion; photochemistry; molecular photoswitches; photochemical upconversion; triplet sensitization; fluorescence modulation;

    Sammanfattning : Manipulating light to meet human needs is pivotal in various research fields and technological applications, ranging from solar energy conversion to photodynamic therapy and fluorescence imaging of cells and tissues. This thesis addresses the spectral mismatches between available light and the specific energy requirements of target photochemical reactions by employing low-energy light to control high-energy photochemistry. LÄS MER

  7. 5. Free energy calculations of G protein-coupled receptor modulation : New methods and applications

    Författare :Willem Jespers; Hugo Gutiérrez-de-Terán; Johan Åqvist; Jonathan Essex; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; G protein-coupled receptor; adenosine receptor; molecular dynamics; free energy perturbation; homology modeling; computer simulations; conformational selectivity; binding free energy.; Biology with specialization in Molecular Biotechnology; Biologi med inriktning mot molekylär bioteknik;

    Sammanfattning : G protein-coupled receptors (GPCRs) are membrane proteins that transduce the signals of extracellular ligands, such as hormones, neurotransmitters and metabolites, through an intracellular response via G proteins. They are abundant in human physiology and approximately 34% of the marketed drugs target a GPCR. LÄS MER