Sökning: "snubber"

Visar resultat 1 - 5 av 7 avhandlingar innehållade ordet snubber.

  1. 1. Cost-effective Cells for High-power Modular Multilevel Converters

    Författare :Matthijs Heuvelmans; Staffan Norrga; Hans-Peter Nee; Rik De Doncker; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MMC; modular multilevel converter; ARCP; IGCT; soft-switching; ZVS; ZCS; snubber; thyristor; SCR; silicon controlled rectifier; HVDC; STATCOM; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : The modular multilevel converter (MMC) topology was introduced in 2003and has since been receiving considerable attention from industry and academia.Notable benefits compared to two- or three-level voltage source convertersare its scalability, low switching losses, low output filter requirementsand ease of adding redundancy combined with fail-safe operation. LÄS MER

  3. 2. 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. 3. 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

  5. 4. High Frequency Model of Electrified Railway Propulsion System for EMC Analysis

    Författare :Kelin Jia; Rajeev Thottappillil; Hans Bängtsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electromagnetic compatibility; railway; propulsion system; multitransmission line; ac motor modeling; vector fitting; fast transient;

    Sammanfattning : A model of the electrified railway propulsion system working in a wide frequency range is studied in this thesis. The high frequency modeling is the first stage to study and predict the Electromagnetic compatibility (EMC) problems in the electrified railway propulsion system, which are safety and reliability issues of high concern. LÄS MER

  7. 5. 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