Search for dissertations about: "switching frequency"

Showing result 1 - 5 of 178 swedish dissertations containing the words switching frequency.

  2. 1. Modeling and Control of Voltage Source Converters Connected to the Grid

    Author : Michael Lindgren; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; voltage source converter; switching frequency; pulse width modulation; IGBT valve; power electronics; small-signal; L-filter; LCL-filter; transfer function; line filter; active filtering; frequency response; sampling frequency;

    Abstract : This thesis deals with the modeling and control of pulse width modulated (PWM) voltage source converters connected to the grid. When voltage source converters are connected to the grid, the power quality and the dynamic performance are affected by the line filter connected between the converter and the grid, and by nonlinearities caused by the switching converter. READ MORE

  4. 2. On high-frequency soft-switching DC-converters for high-voltage applications

    Author : Per Ranstad; KTH; []
    Keywords : soft-switching; dc-converter; high-frequency; high-voltage;

    Abstract : .... READ MORE

  5. 3. Resonant switching and vortex dynamics in spin-flop bi-layers

    Author : Sergiy Cherepov; Vladislav Korenivski; Thomas Silva; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; spin-dynamics; MRAM; vortex; switching; Condensed matter physics; Kondenserade materiens fysik; Magnetism; Magnetism; Mesoscopic physics; Mesoskopisk fysik;

    Abstract : This thesis is a study of the static and dynamic behavior of the magne-tization in spin-flop bi-layers, which consist of two soft ferromagnetic layerscoupled by dipolar forces through a thin nonmagnetic spacer. The focus ofthe work is three fold: collective spin dynamics in the anti-parallel groundstate; resonant switching in the presence of thermal agitation; and static anddynamic behavior of the system in the vortex-pair state, with a particularemphasis on the interlayer core-core interaction. READ MORE

  6. 4. Voltage Transients in the Field Winding of Salient Pole Wound Synchronous Machines : Implications from fast switching power electronics

    Author : Roberto Felicetti; Urban Lundin; Jon Kjellin; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; apparent resistance; cable modeling; current control; transmission line model; eddy currents; field winding; frequency analysis response; Fourier Transform; impedance mismatch; main inductance; overvoltage; parasitic capacitance; partial discharge; quality factor; ringing; slew rate; stray inductance; voltage gradient; winding resonance frequency;

    Abstract : Wound Field Synchronous Generators provide more than 95% of the electricity need worldwide. Their primacy in electricity production is due to ease of voltage regulation, performed by simply adjusting the direct current intensity in their rotor winding. READ MORE

  7. 5. 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