Sökning: "power conversion system"

Visar resultat 21 - 25 av 217 avhandlingar innehållade orden power conversion system.

1. 21. Enhanced District Heating Technology : Maintaining Future System Feasibility

   Författare :Helge Averfalk; Sven Werner; Urban Persson; Mei Gong; Patrick Lauenburg; Kerstin Sernhed; Per-Olof Johansson Kallioniemi; Louise Ödlund; Högskolan i Halmstad; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : When heat demand and high temperature heat supply gradually decreases in the future, then it will effect district heating systems ability to compete on the heat market. A good way to mitigate less district heating feasibility is to operate systems with lower temperature levels and the most conceivable way to achieve lower temperature levels is to decrease return temperatures. LÄS MER

3. 22. A novel solar-driven system for two-step conversion of CO2 with ceria-based catalysts

   Författare :Bo Wei; Reza Fakhrai; Torsten Fransson; Nader Jand; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CO2 conversion; solar; ceria; thermogravimetric test; exergy analysis; simulink; fluidized bed; gas-solid flow; simulation; Energiteknik; Energy Technology;

   Sammanfattning : Global warming is an unequivocal fact proved by the persistent rise of the average temperature of the earth. IPCC reported that scientists were more than 90 % certain that most of the global warming was caused by increasing concentrations of greenhouse gases (GHG) produced by human activities. LÄS MER

4. 23. Hybrid Solar Gas-Turbine Power Plants : A Thermoeconomic Analysis

   Författare :James Spelling; Andrew Martin; Björn Laumert; David Tomas Sanchez Martinez; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; solar thermal power; hybrid gas-turbine; thermoeconomics; koncentrerad solenergi; gas-turbiner; ekonomisk analys;

   Sammanfattning : The provision of a sustainable energy supply is one of the most importantissues facing humanity at the current time, and solar thermal power hasestablished itself as one of the more viable sources of renewable energy. Thedispatchable nature of this technology makes it ideally suited to forming thebackbone of a future low-carbon electricity system. LÄS MER

5. 24. On soft-switching isolated AC/DC converters without auxiliary circuit

   Författare :Staffan Norrga; Stefan Östlund; Rik De Doncker; KTH; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

7. 25. All Digital Polar Transmitter Design for Software Defined Radio : Architecture and Low Power Circuit Implementation

   Författare :Liang Rong; Li-Rong Zheng; Henrik Sjöland; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Switching Power Amplifier; All Digital Polar Transmitter; Lowpass Sigma Delta Modulation; Software Defined Radio; RFID; H-Bridge Architecture; Resonating; Filter Matching Network.; SRA - ICT; SRA - Informations- och kommunikationsteknik;

   Sammanfattning : The evolving wireless communication technology is aiming highdata rate, high mobility, long distance and at the meantime, co-existwith various different standards. This developing trend requires ahighly linear transceiver system and it causes the problem of lowefficiency due to the large crest factor of signals. LÄS MER