Sökning: "combined AC and DC"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden combined AC and DC.

1. 1. On Stability Enhancement in AC/DC Power Systems through Multi-terminal HVDC Controllers

   Författare :Omar Kotb; Mehrdad Ghandari; Oriol Gomis Bellmunt; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; AC DC power system; hybrid MTDC; multi-terminal HVDC; small signal stability; VSC-MTDC; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Due to the increasing share of renewable energy sources in modern power systems and electricity market deregulation, heavy inter-regional and cross-border power flows are becoming a commonplace in system operation. Moreover, large-scale integration of renewable energy sources is expected to pace up, therefore new solutions have to be developed to integrate these intermittent sources, which are also characterized by being distributed over large geographical areas, such as offshore wind farms. LÄS MER

3. 2. Enhanced Dielectric Response Methods for the Characterization of Dielectric Materials

   Författare :Jing Hao; Nathaniel Taylor; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; FDS; non-contact; dielectric response; combined AC and DC; space-charge polarization;

   Sammanfattning : Dielectric response measurement is widely used for condition assessment of high voltage equipment and for characterizing candidate materials. Measurement with high accuracy and reliability is important in all stages of the lifetime of high voltage equipment, from manufacture to replacement decision. LÄS MER

4. 3. Stark Spectroscopy, Lifetimes and Coherence Effects in Diatomic Molecular Systems

   Författare :Annie Hansson; Peder Royen; Michel Herman; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diatomic; dipole moment; Stark effect; lifetimes; transition moment; coherence effects; EIT; Autler-Townes; Chemical physics; Kemisk fysik;

   Sammanfattning : In this dissertation is exemplified how different laser based methods are applied in high-resolution spectroscopic studies of internal properties of diatomic molecules.A molecular beam apparatus assembly is described, where a laser ablation source is combined with a time-of-flight mass spectrometer. LÄS MER

5. 4. Modelling and control of a line-commutated HVDC transmission system interacting with a VSC STATCOM

   Författare :Paulo Fischer de Toledo; Hans-Peter Nee; Gustaf Ohlsson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Keywords : HVDC transmission; LCC – Line-commutated Current-source Converter; STATCOM; VSC – Voltage Source Converter; Space-Vector complex vector ; transfer-function; frequency-domain analysis; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Sammanfattning : The interaction of an HVDC converter with the connected power system is of complex nature. An accurate model of the converter is required to study these interactions. The use of analytical small-signal converter models provides useful insight and understanding of the interaction of the HVDC system and the connected system components. LÄS MER

7. 5. Microwave Power Devices and Amplifiers for Radars and Communication Systems

   Författare :Sher Azam; Qamar ul Wahab; Erik Janzén; Georg Boeck; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Semiconductor physics; Halvledarfysik;

   Sammanfattning : SiC MESFETs and GaN HEMTs posses an enormous potential in power amplifiers at microwave frequencies due to their wide bandgap features of high electric field strength, high electron saturation velocity and high operating temperature. The high power density combined with the comparably high impedance attainable by these devices also offers new possibilities for wideband power microwave systems. LÄS MER