Sökning: "Lena Wind"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Lena Wind.

  1. 1. Energy Evaluation for DC/DC Converters in DC-Based Wind Farms

    Författare :Lena Max; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DC DC converter; loss evaluation; measurements; hard switching converters; wind energy; resonant converters; snubber design;

    Sammanfattning : In this thesis the suitability of three topologies for DC/DC converters in a DC wind farm grid is investigated from an energy efficiency and energy production cost point of view. The three selected topologies are the fullbridge converter, the single active bridge converter and the series parallel resonant converter. LÄS MER

  3. 2. Design and control of a DC collection grid for a wind farm

    Författare :Lena Max; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DC collection grid; fault handling; DC DC converter; wind energy; control design; loss evaluation;

    Sammanfattning : In this thesis, the internal DC collection grid for a wind farm is investigated regarding the design, losses and dynamic operation for both normal operating conditions and for different fault conditions. The main advantage for the DC collection grid is the considerably lower weight of the 1 kHz transformers in the DC/DC converters compared to the equivalent 50 Hz transformers. LÄS MER

  4. 3. Vindkraft och lokala förankringsprocesser : Perspektiv på deltagande, förståelse och acceptans

    Författare :Sanna Mels; Lars Aronsson; Lena Grip; Renard S:t Clair; Marie Stenseke; Karlstads universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; local consultation processes; off-shore wind power; planning; legitimacy; participation; förankring; havsbaserad vindkraft; planering; legitimitet; medborgardeltagande; Kulturgeografi; Human Geography;

    Sammanfattning : This study examines different meanings attached to and practices adopted during Swedish local consultation processes on offshore wind power projects. It analyses the role played by those processes in a democratic planning context, as well as the ways in which they are implemented. It also identifies overarching process models. LÄS MER

  5. 4. Dynamics of Energy Systems - Methods of analysing technology change

    Författare :Lena Neij; Internationella miljöinstitutet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energy research; evaluation; market transformation; PV modules; wind power; experience curves; air-distribution; lighting; vintage models; sustainable energy; renewable energy; energy efficiency; Energy; energy system; Energiforskning; Environmental technology; pollution control; Miljöteknik; kontroll av utsläpp;

    Sammanfattning : Technology change will have a central role in achieving a sustainable energy system. This calls for methods of analysing the dynamics of energy systems in view of technology change and policy instruments for effecting and accelerating technology change. In this thesis, such methods have been developed, applied, and assessed. LÄS MER

  7. 5. Alpine lake sediment archives and catchment geomorphology : causal relationships and implications for paleoenvironmental reconstructions

    Författare :Lena Rubensdotter; Gunhild Rosqvist; Ingmar Borgström; Eve Arnold; Jens-Ove Näslund; Catherine Souch; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; alpine lakes; geomorphology; lacustrine sedimentation; slope processes; glaciofluvial; Holocene; Swedish Lapland; Physical geography; Naturgeografi;

    Sammanfattning : Lake sediments are frequently used as archives of climate and environmental change. Minerogenic sediment variability in alpine lakes is often used to reconstruct past glacier and slope process activity. Alpine lake sediments can however have many different origins, which may induce errors in paleoenvironmental reconstructions. LÄS MER