Sökning: "frequency converters"

Visar resultat 1 - 5 av 166 avhandlingar innehållade orden frequency converters.

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

   Författare :Michael Lindgren; Chalmers tekniska högskola; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

3. 2. High Frequency (MHz) Resonant Converters using GaN HEMTs and Novel Planar Transformer Technology

   Författare :Hari Babu Kotte; kent Bertilsson; Bengt Oelmann; Noel Shammas; Torbjörn Thiringer; Per Karlsson; Mittuniversitetet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; GaN HEMTs; MHz Frequency; Resonant Converters; Planar Transformer Technology;

   Sammanfattning : The increased power consumption and power density demands of moderntechnologies have increased the technical requirements of DC/DC and AC/DC powersupplies. In this regard, the primary objective of the power supply researcher/engineeris to build energy efficient, high power density converters by reducing the losses andincreasing the switching frequency of converters respectively. LÄS MER

4. 3. Multilevel three-phase dual active bridge dc-dc converters - A study on converter modulation, capacitive energy requirement, ZVS boundaries, MFT's winding connections, and core losses

   Författare :Babak Alikhanzadehalamdari; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; high-voltage power converters; dual active bridge; harmonic analysis; three-phase system; medium-frequency transformer; capacitor sizing; multilevel converters; high power-density systems; transformer winding connection; core loss modeling; dc collector network; soft-switching converters;

   Sammanfattning : The collection and transmission of power from offshore wind turbines using dc have advantages over the ac system. One of the enabling technologies for deploying dc collection is the dc-dc converter that boosts the dc output from the turbine to the medium-voltage dc level of the collection grid. LÄS MER

5. 4. Silicon-Carbide-Based High-Voltage Submodules for HVDC Voltage-Source Converters

   Författare :Keijo Jacobs; Hans-Peter Nee; Staffan Norrga; Marc Hiller; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Silicon carbide; HVDC converters; voltage source converters; modular multilevel converters; submodule topologies; metal-oxide-semiconductor field-effect transistor MOSFET ; insulated-gate bipolar-transistor IGBT ; power semiconductor devices; high-voltage; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : In order to transition to renewable energy sources and simultaneously meet the increasing demand for electrical energy, highly flexible and efficient grids are required. High-voltage direct-current (HVDC) transmission and grids are foreseen to be a vital part of the future electricity grid. LÄS MER

7. 5. Modeling of Modular Multilevel Converters for Stability Analysis

   Författare :Luca Bessegato; Stefan Östlund; Staffan Norrga; Lennart Harnefors; Xiongfei Wang; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Modular multilevel converters MMCs ; stability; admittance; frequency-domain analysis; linearization techniques; current control; voltage control; ac ac converters; railway engineering.; Modulära multinivåomvandlare MMC ; stabilitet; admittans; frekvensanalys; linjäriseringsmetoder; strömreglering; spänningsreglering; ac ac omvandlare; järnvägsteknik.; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Modular multilevel converters (MMCs) have recently become the state-of-the-art solution for various grid-connected applications, such as high-voltage direct current (HVDC) systems and flexible alternating current transmission systems (FACTS). Modularity, scalability, low power losses, and low harmonic distortion are the outstanding properties that make MMCs a key technology for a sustainable future. LÄS MER