Sökning: "commutation"

Visar resultat 1 - 5 av 29 avhandlingar innehållade ordet commutation.

  1. 1. Studies on Current Commutation in Hybrid DC-breakers

    Författare :Jesper Magnusson; Göran Engdahl; Magne Runde; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Commutation; Hybrid DC-breakers; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Compared to conventional AC-circuit breakers, a DC-breaker has to act fast and force the current down to zero. Many different DC-breaker topologies are available, and this thesis is focused on the hybrid DC-breaker comprising a mechanical switch and high power semiconductors. LÄS MER

  3. 2. On soft-switching isolated AC/DC converters without auxiliary circuit

    Författare :Staffan Norrga; Stefan Östlund; Rik De Doncker; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical power technology; voltage source converter; cycloconverter; isolated converter; medium frequency transformer; soft switching; modulation; commutation; wind power; electric traction; Elkraftteknik; Electric power engineering; Elkraftteknik;

    Sammanfattning : The thesis is concerned with a class of power electronic converter systems that permit bidirectional AC/DC conversion with galvanic separation of the AC and DC sides by a transformer operating at elevated frequency. The systems consist of a capacitively snubbered voltage source converter and a cycloconverter, separated by the mentioned transformer. LÄS MER

  4. 3. Ljudstrukturen i dialekten i Rödåliden : Auditiv analys av fonemen i en norrländsk dialekt i början av 2000-talet

    Författare :Rune Westerlund; Lars-Erik Edlund; Eva Strangert; Gjert Kristoffersen; Umeå universitet; []
    Nyckelord :HUMANIORA; HUMANITIES; functional; informants; commutation; distribution; tonal accent; circumflex accent; auditory; cacuminal; Västerbotten; Swedish language; Svenska språket;

    Sammanfattning : This study investigates the sound structure of the dialect of the Rödåliden area in the province of Västerbotten in Northern Sweden. The aim is to describe the phonological system with a structural approach. LÄS MER

  5. 4. Orthogonal Polynomials, Operators and Commutation Relations

    Författare :John Musonda; Sergei Silvestrov; Sten Kaijser; Anatoliy Malyarenko; Natan Kruglyak; Irina Asekritova; Viktor Abramov; Mälardalens högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics Applied Mathematics; matematik tillämpad matematik;

    Sammanfattning : Orthogonal polynomials, operators and commutation relations appear in many areas of mathematics, physics and engineering where they play a vital role. For instance, orthogonal functions in general are central to the development of Fourier series and wavelets which are essential to signal processing. LÄS MER

  7. 5. Ultra-fast electromechanical commutation switch for hybrid breakers

    Författare :Mrunal Parekh; Marley Becerra Garcia; Christian Franck; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : In a power system with the ability to integrate geographically spread diverse renewable energy sources, there is a need for efficient control of the power flow and effective power transmission. Power electronics can provide this controllability, at the expense of conductive losses in the used components. LÄS MER