Search for dissertations about: "m2c"

Showing result 1 - 5 of 8 swedish dissertations containing the word m2c.

2. 1. Control, Modulation and Implementation of Modular Multilevel Converters

   Author : Antonios Antonopoulos; Hans-Peter Nee; Colin Oates; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Modular Multilevel Converter; Modulation; Feedback Control; Open-Loop Control; Implementation; Prototype; High-Performance Motor Drives; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Abstract : Denna avhandling behandlar analys och styrning av den modulära multinivå omvandlaren (M2C). M2C är en lovande omvandlarteknologi för högspända högeffekttillämpningar. Anledningen till detta är låg distorsion i utstorheterna kan uppnås med låg  medelswitchfrekvens per switch och utan utgångsfilter. READ MORE

4. 2. On the Internal Dynamics and AC-Motor Drive Application of Modular Multilevel Converters

   Author : Antonios Antonopoulos; Hans-Peter Nee; Lennart Harnefors; Hirofumi Akagi; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Capacitor-Voltage Control; Controller Interaction; Converter Control; Energy Balance; Lyapunov Stability; Medium-Voltage Drives; Modular Multilevel Converter; Modulation; Open-Loop Control; Optimization; Variable-Speed Drives; Voltage-Source Converter.; Energibalans; Kondensatorspänningsstyrning; Lyapunov-stabilitet; Mellan-spänning drivsystem; Modulation; Modulär multinivåomvandlare; Omvandlarstyrning; Optimering; Regulatorväxelverkan; Spänningsstyva omvandlare; Varvtalsstyrda motordrifter; Öppen styrning.; Electrical Engineering; Elektro- och systemteknik;

   Abstract : This thesis is an effort to investigate the operation and the performanceof modular multilevel converters (M2Cs). Proven to be the most promisingtopology in high-voltage high-power applications, it is necessary to put aneffort in understanding the physical laws that govern the internal dynamicsof such converters, in order to design appropriate control methods. READ MORE

5. 3. Secondary hardening in some low-chromium hot-work tool steels

   Author : Jörgen Andersson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LEAP; coarsening; nitriding; SEM; TEM; vanadium; precipitation hardening;

   Abstract : Low-chromium hot-work tool steels combine good heat conductivity with excellent tempering resistance. This property combination has made these steels ideal for die casting and extrusion. READ MORE

6. 4. Microstructure and Mechanical Properties of High Chromium Steel Weld Metals

   Author : Guang-Jun Cai; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : The microstructure of three types of Cr steel weld metals, containing 5%, 9% and 12% chromium, was studied in different heat treated conditions using optical microscopy, analytical transmission electron microscopy and atom probe field-ion microscopy. The mechanical properties of the weld metals were investigated. READ MORE

7. 5. Some aspects of convection as well as graphite and carbide formations during casting

   Author : Fareed Ashraf Khan; Michael Vynnycky; Pär Jönsson; Bo Rogberg; Hasse Fredriksson; Jessica Elfsberg; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; carbides; heat treatment; cast iron; ball bearing steel; casting; cooling rate; structure analysis; nodule distribution; melt stirring; nuclei; karbider; värmebehanding; gjutjärn; kullagerstål; gjutning; kylningshastighet; strukturanalys; nodulefördelning; smältrörelse; kärnor.; Metallurgical process science; Metallurgisk processvetenskap;

   Abstract : It is an established fact that segregation during casting affects the physical properties of carbon-based ferro alloys; this motivates the study of the segregation behaviour of carbon and carbide-forming solute elements. In this context, this thesis investigates two different situations: the effects of cooling rate and turbulence on the precipitation behaviour of the graphite nodules in nodular cast iron; the nature of carbide precipitation in a bearing steel grade and the effects of subsequent soaking on these carbides. READ MORE