Sökning: "optimum efficiency"

Visar resultat 1 - 5 av 127 avhandlingar innehållade orden optimum efficiency.

1. 1. High efficiency power amplifiers for wireless communications

   Författare :Hossein Mashad Nemati; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; load modulation; GaN; supply modulation; LDMOS; efficiency; Power amplifier; MMIC; mHEMT; transmitter architecture;

   Sammanfattning : This thesis presents state-of-the-art high efficiencyharmonically-tuned power amplifiers (PAs) and investigates thecharacteristics and potentials of such amplifiers in two of the mostpromising efficiency enhancement techniques, dynamic supply and load modulation.In this work, a 10 W LDMOS harmonically-tuned PA with 80% power-added-efficiency (PAE) isrealized at 1 GHz. LÄS MER

3. 2. Study of Induction Machines with Rotating Power Electronic Converter

   Författare :Yanmei Yao; Chandur Sadarangani; Zi-Qiang Zhu; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Brushless induction machine; efficiency improvement; optimum efficiency; rotating power electronic converter; unity power factor; variable power factor; wound rotor induction machine; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis investigates a novel induction machine topology that uses a rotating power electronic converter. Steady-state and dynamic performance of the topology is studied to understand its operational principle. Furthermore the potential of improving its efficiency and power factor is investigated. LÄS MER

4. 3. Increasing Energy Efficiency in Electric Trains Operation : Driver Advisory Systems and Energy Storage

   Författare :Nima Ghaviha; Erik Dahlquist; Markus Bohlin; Fredrik Wallin; Rob M.P. Goverde; Mälardalens högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Driver Advisory System; Catenary-free Operation; Electric Train; Electric Multiple Unit; Battery; Energy Efficiency; Energy Storage; Speed Profile Optimization; Energy- and Environmental Engineering; energi- och miljöteknik;

   Sammanfattning : Electric traction is the most efficient traction system in the railway transportation. However, due to the expensive infrastructure and high power demand from the grid, the share of electric trains in the railway transportation is still lower than other trains. LÄS MER

5. 4. Voyage optimization algorithms for ship safety and energy-efficiency

   Författare :Helong Wang; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energy efficiency; Dijkstra’s algorithm; Voyage optimization algorithms; Genetic algorithm; Ship safety; Expected time of arrival;

   Sammanfattning : Currently, over 90% of the world’s trade is transported by sea. The environmental impacts from shipping and societal challenges of human and property losses caused by ship accidents are pressuring the shipping industry for more energy efficiency and enhanced safety. LÄS MER

7. 5. Numerical Optimization of a propeller in a given wake and behind a ship

   Författare :Kaijia Han; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; propeller geometry; pressure fluctuation; correction; full scale; efficiency; RANS; cavitation; grid density; verification; delivered power; optimization; Hamburg test case; iteration number;

   Sammanfattning : The work presented in this thesis includes two stages in a research project at the Rolls-Royce University Technology Center (UTC) at Chalmers Technology University. The objective of the project is to develop an optimization technique for ship/propeller interaction. LÄS MER