Avancerad sökning

Hittade 4 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Experimental Vertical Axis Wind Turbine System

   Författare :Jon Kjellin; Uppsala universitet; []
   Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Vertical axis wind turbines may have mechanical advantages compared to conventional horizontal axis wind turbines, which make vertical turbines interesting to study. A 12 kW straight-bladed Darrieus turbine has been designed and constructed by the Division of Electricity at Uppsala University. LÄS MER

3. 2. 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

4. 3. Improving the functionality of synchronous machines using power electronics

   Författare :Fredrik Evestedt; Urban Lundin; C. Johan. D. Abrahamsson; Jon Kjellin; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Power electronics; Synchronous machines; Excitation systems; Magnetic thrust bearing; Starting synchronous machines; Split rotor; Rotating electronics; Magnetic fields; Measurement systems; Unbalanced magnetic pull; Harmonics; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Sammanfattning : With the advent of modern power electronics there is reason to explore what can be achieved when it is applied to a mature technology like synchronous machines. In this text several concepts will be presented on how it is possible to control forces and how to get better performance out of synchronous machines by using power electronics. LÄS MER

5. 4. Voltage Transients in the Field Winding of Salient Pole Wound Synchronous Machines : Implications from fast switching power electronics

   Författare :Roberto Felicetti; Urban Lundin; Jon Kjellin; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; apparent resistance; cable modeling; current control; transmission line model; eddy currents; field winding; frequency analysis response; Fourier Transform; impedance mismatch; main inductance; overvoltage; parasitic capacitance; partial discharge; quality factor; ringing; slew rate; stray inductance; voltage gradient; winding resonance frequency;

   Sammanfattning : Wound Field Synchronous Generators provide more than 95% of the electricity need worldwide. Their primacy in electricity production is due to ease of voltage regulation, performed by simply adjusting the direct current intensity in their rotor winding. LÄS MER