Sökning: "Power Coefficient"

Visar resultat 1 - 5 av 156 avhandlingar innehållade orden Power Coefficient.

1. 1. Frequency response by wind farms in power systems with high wind power penetration

   Författare :Mattias Persson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; inertia estimation; frequency control; power system stability; wind power integration; Power system; synthetic inertia;

   Sammanfattning : The integration of variable speed wind turbines (VSWT) in power systems is increasing in order to reduce the emission of green house gases. This increase of power electronic converter interfaced generation causes a decrease of power system inertia, increasing the risk of load shedding and system frequency instability. LÄS MER

3. 2. Roller skis' rolling resistance and grip characteristics : influences on physiological and performance measures in cross-country skiers

   Författare :Mats Ainegren; Peter Carlsson; Marko Laaksonen; Mittuniversitetet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Adjustable grip; blood lactate; centre of pressure; cycle length; cycle rate; economy; efficiency; friction coefficient; heart rate; normal force; OBLA; oxygen uptake; power; ratcheted wheel; ratings of perceived exertion; roller skis; rolling resistance; tangential force; time to exhaustion;

   Sammanfattning : The aim of this thesis was to investigate roller ski characteristics; classical and freestyle roller skis’ rolling resistance coefficients (μR) and classical style roller skis’ static friction coefficients (μS), and to study the influence of different μR and μS on cross-country skiers’ performance and both physiological and biomechanical indices. The aim was also to study differences in skiing economy and efficiency between recreational skiers, female and male junior and senior elite cross-country skiers. LÄS MER

4. 3. Combined Electrical Power Generation using Solar and Wind

   Författare :Ingemar Mathiasson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wave length bands; atmospheric transmittance; energy storage; Wind turbine; wind speed; quantum dots; electrical load.; extinction coefficient; silicon solar cell; solar cell;

   Sammanfattning : The need for systems for renewable electrical power production is enormous worldwide.This applies to systems of varying size and capacity. From small systems for household purposes up to large systems for regional purposes. If possible, all systems should be linked in a common power grid. LÄS MER

5. 4. Numerical Modelling and Statistical Analysis of Ocean Wave Energy Converters and Wave Climates

   Författare :Wei Li; Isberg Jan; Jens Peter Kofoed; Uppsala universitet; []
   Nyckelord :Wave power; Wave energy converter; Gravity-based foundation; Power absorption; Wave spectrum; Linear generator; Frequency domain; Wave climate; Ocean wave modelling; Mixed-distribution model; Bivariate distribution; Archimedean copula;

   Sammanfattning : Ocean wave energy is considered to be one of the important potential renewable energy resources for sustainable development. Various wave energy converter technologies have been proposed to harvest the energy from ocean waves. This thesis is based on the linear generator wave energy converter developed at Uppsala University. LÄS MER

7. 5. Vertical Axis Wind Turbines : Electrical System and Experimental Results

   Författare :Jon Kjellin; Hans Bernhoff; Mats Leijon; Jonny Hylander; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VAWT; H-rotor; start-up; all-electric control; Power Coefficient; stall; tip speed ratio; Renewable energy; Measurement systems; PM-generator;

   Sammanfattning : The wind power research at the division of Electricity at Uppsala University is aimed towards increased understanding of vertical axis wind turbines. The considered type of wind turbine is an H-rotor with a directly driven synchronous generator operating at variable speed. LÄS MER