Sökning: "dc 3"

Visar resultat 1 - 5 av 296 avhandlingar innehållade orden dc 3.

  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. On the design of hybrid DC-breakers consisting of a mechanical switch and semiconductor devices

    Författare :Jesper Magnusson; Göran Engdahl; Staffan Norrga; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DC; circuit breaker; hybrid breaker; DC systems; DC; brytare; hybridbrytare; likström;

    Sammanfattning : The interest of using direct current in networks for both transmission and distribution of power is increasing due to the higher efficiency compared to the alternating current used today. As no natural zero crossings exist in direct current, the interruption of fault currents becomes a challenge. LÄS MER

  4. 3. Highly-Efficient Energy Harvesting Interfaces for Implantable Biosensors

    Författare :Janko Katic; Ana Rusu; Saul Rodriguez; Gabriel Rincón-Mora; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energy harvesting interface; thermoelectric generator; glucose biofuel cell; power management; dc-dc converter; boost converter; zero-current switching; zero-voltage switching; implantable biosensor; Energiskördsgränssnitt; termoelektrisk generator; glukosbiobränslecell; energihantering; DC-DC-omvandlare; boost-omvandlare; inplanterbar biosensor; Informations- och kommunikationsteknik; Information and Communication Technology;

    Sammanfattning : Energy harvesting is identified as an alternative solution for powering implantable biosensors. It can potentially enable the development of self-powered implants if the harvested energy is properly handled. This development implies that batteries, which impose many limitations, are replaced by miniature harvesting devices. LÄS MER

  5. 4. 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

  7. 5. Thin films of YBa2Cu3O7 deposited by co-evaporation, Josephson junctions, and DC-SQUIDS

    Författare :Per-Åke Nilsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; microbridge; Josephson junction; BaF2< sub>; co-evaporation; sub- #956; YBa2< sub>Cu3< sub>O7< sub>; bi-crystal; DC-SQUID; thin film; m;

    Sammanfattning : .... LÄS MER