Sökning: "Frequency converters"

Visar resultat 11 - 15 av 166 avhandlingar innehållade orden Frequency converters.

  1. 11. High-Efficiency SiC Power Conversion : Base Drivers for Bipolar Junction Transistors and Performance Impacts on Series-Resonant Converters

    Författare :Georg Tolstoy; Hans-Peter Nee; Stig Munk-Nielsen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Silicon Carbide; Bipolar Junction Transistor BJT ; Resonant converter; Series-resonant converter SLR ; Base drive circuits; High- Efficiency Converters; High-Frequency Converters; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : This thesis aims to bring an understanding to the silicon carbide (SiC) bipolar junction transistor (BJT). SiC power devices are superior to the silicon IGBT in several ways. They are for instance, able to operate with higher efficiency, at higher frequencies, and at higher junction temperatures. LÄS MER

  3. 12. 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

  4. 13. Modelling approaches for audio frequency power transformers

    Författare :Julius Krah; KTH; []
    Nyckelord :power transformer; audio frequency; loss; hysteresis; eddy currents; skin effect. Leakage inductance;

    Sammanfattning : The development of HVDC converters, local generation andtractions systems increases the demand for power converters.While a lot of studies have been conducted on the powerelectronics, there are still open questions concerning thecontained power transformer that operates at a few kilohertz. LÄS MER

  5. 14. Multiantenna Wireless Architectures with Low Precision Converters

    Författare :Yasaman Ettefagh; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; massive MIMO; fronthaul link; normal approximation; random coding union bound with parameter s; data converters; outage probability;

    Sammanfattning : One of the main key technology enablers of the next generation of wireless communications is massive multiple input multiple output (MIMO), in which the number of antennas at the base station (BS) is scaled up to the order of tens or hundreds. It provides considerable energy and spectral efficiency by spatial multiplexing, which enables serving multiple user equipments (UEs) on the same time and frequency resource. LÄS MER

  7. 15. Classical and Quantum Correlations in Microwave Frequency Combs

    Författare :Shan Williams Jolin; David B. Haviland; Pertti Hakonen; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Josephson junctions; parametric amplifiers; multipartite entanglement; microwaves; frequency comb; Gaussian states; bichromatic pump; surface acoustic waves; IQ mixer; fully inseparable states; superconducting circuits; hybrid circuits; intermodulation; nonlinear resonators; Material and Nano Physics; Material- och nanofysik;

    Sammanfattning : Denna avhandling undersöker korrelationer i frekvensdomänen, av både klassiskt och kvantmekaniskt ursprung, i icke-linjära mikrovågskretsar. Syftet är att utveckla en kompakt metod för att generera kvantmekaniska korrelationer mellan harmoniska oscillatorer (s.k. LÄS MER