Search for dissertations about: "high dV dt."

Found 4 swedish dissertations containing the words high dV dt..

  1. 1. Detection of Partial Discharges at Fast Rising Voltages

    Author : Thomas Hammarström; Chalmers University of Technology; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Partial discharges; cavities; repetitive voltages; high dV dt.; square like voltages; short rise time; measurements;

    Abstract : The present demand for higher efficiency and flexibility in the energy sector has ledto an increased use of power electronic generated waveforms as these allow energyconversion between different frequencies including DC. The generated waveformsare usually synthesized by so called Pulse Width Modulation (PWM) techniques,where the desired waveform is approximated by a number of square shaped pulseswith a short rise time. READ MORE

  2. 2. Partial Discharges at Repetitive Rapidly Changing Voltages

    Author : Elisabeth Lindell; Chalmers University of Technology; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; high dV dt; oil paper insulation.; repetitive voltages; short rise time; partial discharge measuring techniques; twisted pair; square-like voltages; corona; Partial discharges PDs ;

    Abstract : Electrical insulation can today be exposed to voltages having considerably higherfrequency components than the conventional power frequency AC 50 Hz or 60 Hz,for example due to the increased use of power electronics in power systems. Thishas in a number of cases caused unexpected behaviour, including failures. READ MORE

  3. 3. Partial Discharges at Fast Rising Voltages

    Author : Thomas Hammarström; Chalmers University of Technology; []
    Keywords : TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; short rise time; cavities; high dV dt.; measurements; Partial discharges; square like voltages; repetitive voltages;

    Abstract : The present demand for higher efficiency and flexibility in the energy sector has led to an increased use of power electronic generated waveforms as these allow energy conversion between different frequencies including DC. The generated waveforms are usually synthesized by so called Pulse Width Modulation (PWM) techniques, where the desired waveform is approximated by a number of square shaped pulses with a short rise time. READ MORE

  4. 4. On Gate Drivers for MOS-Controlled Power Devices and dv-dt Filters for Train Traction Converters

    Author : Erik Velander; Hans-Peter Nee; Francesco Iannuzzo; KTH; []
    Keywords : Power semiconductor devices; DC-AC power converters; Silicon carbide; Insulated gate bipolar transistors; P-i-n diodes; Schottky diodes; Traction motors; Power MOSFET; Krafthalvledare; DC-AC kraftomvandlare; kiselkarbid; IGBT; P-i-n dioder; Schottky dioder; traktionsmotorer; Effekt-MOSFET; Electrical Engineering; Elektro- och systemteknik;

    Abstract : In this thesis, low-loss gate-drive solutions and a proposed dv/dt-filter have been investigated with focus on train traction converters with dv/dt constraints.By using the silicon carbide (SiC) junction field-effect transistor (JFET), the switching losses can be significantly reduced compared to the commonly used insulated-gate bipolar transistor (IGBT), but complex gate-driver solutions are required for high utilization in terms of loss reduction. READ MORE