Search for dissertations about: "converter efficiency"

Showing result 16 - 20 of 92 swedish dissertations containing the words converter efficiency.

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

    Author : Staffan Norrga; Stefan Östlund; Rik De Doncker; KTH; []
    Keywords : 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;

    Abstract : 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. READ MORE

  4. 17. Grid-Connected Voltage Source Converter - Control Principles and Wind Energy Applications

    Author : Jan Svensson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind turbine; voltage source converter; voltage angle control; frequency response; vector current control; grid-connected; forced-commutated; measurements;

    Abstract : The thesis focuses on a forced-commutated voltage source converter (VSC) connected to a grid in a wind energy application. The work consists of four parts. The first part addresses the type of electrical system which should be used in a wind turbine. READ MORE

  5. 18. On Design of a Compact Primary Switched Conversion System for Electric Railway Propulsion

    Author : Tommy Kjellqvist; Stefan Östlund; Alfred Rufer; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Isolated AC DC converter; Mutual commutation; Soft Switching; Cyclo converter; Medium-Frequency Transformer; Electric Railway Propulsion; Electrical engineering; Elektroteknik;

    Abstract : In this thesis, a compact and light primary switched conversion system for AC-fed railway propulsion is investigated. It is characterized by soft switching of all converter stages and a source commutated primary converter comprising series connected valves. READ MORE

  6. 19. On Reliability of SiC Power Devices in Power Electronics

    Author : Diane-Perle Sadik; Hans-Peter Nee; Per Ranstad; Nando Kaminski; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Silicon Carbide; Metal-Oxide-Semiconductor Field-Effect Transistor MOSFET ; Junction Field-Effect Transistor JFET ; Bipolar Junction Transistor BJT ; Reliability; Failure Analysis; Reliability Testing; Short- Circuit Currents; Humidity; Resonant converter; Series-resonant converter SLR ; Base drive circuits; Gate drive circuits; Life-Cycle Cost Analysis LCCA ; Kiselkarbid; MOSFETar; JFETar; Bipolär Junction Transistor BJT ; Tillförlitlighet; Robusthet; Felanalys; Tillförlitlighetstestning; Kortslutningsströmmar; Luftfuktighet; Resonansomvandlare; Serie-resonansomvandlare SLR ; Basdrivkretsar; Gate-drivkretsar; Felskydd; Livscykelkostnadsanalys; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Silicon Carbide (SiC) is a wide-bandgap (WBG) semiconductor materialwhich has several advantages such as higher maximum electric field, lowerON-state resistance, higher switching speeds, and higher maximum allowablejunction operation temperature compared to Silicon (Si). In the 1.2 kV - 1. READ MORE

  7. 20. Modeling of a Free Piston Energy Converter

    Author : Jakob Fredriksson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Free piston engine; detailed chemistry; variable compression; computational fluid dynamics CFD ; combustion;

    Abstract : ABSTRACTThe Free Piston Energy Converter (FPEC) is a new type of automotive prime mover, offering high efficiency in conjunction with low emissions. The FPEC essentially consists of two opposing cylinders with a linear alternator incorporated in-between that produces electric power directly. READ MORE