Sökning: "Mode Stability Analysis"

Visar resultat 1 - 5 av 100 avhandlingar innehållade orden Mode Stability Analysis.

1. 1. Control and Analysis of Pulse-Modulated Systems

   Författare :Stefan Almér; Ulf Jönsson; Gilead Tadmor; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Pulse-width modulation; Periodic systems; Stability analysis; Harmonic analysis; Lyapunov methods; Dynamic phasors; Harmonic transfer function; Switched mode power converters; Sampled data modeling; H-infinity synthesis; Optimization; systems theory; Optimeringslära; systemteori;

   Sammanfattning : The thesis consists of an introduction and four appended papers. In the introduction we give an overview of pulse-modulated systems and provide a few examples of such systems. Furthermore, we introduce the so-called dynamic phasor model which is used as a basis for analysis in two of the appended papers. LÄS MER

3. 2. Receptivity, Stability and Sensitivity analysis of two- and three-dimensional flows

   Författare :Guillaume Chauvat; Ardeshir Hanifi; Dan S. Henningson; Ulrich Rist; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary-layers; stability; receptivity; sensitivity; transition; mode decomposition; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : This work deals with various aspects of boundary-layer stability. Modal and non-modal approaches are first used in the study of the global stability of a jet in crossflow. LÄS MER

4. 3. Reliability-based Assessment of Concrete Dam Stability

   Författare :Marie Westberg; Avdelningen för Konstruktionsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; assessment; stability; concrete dam; structural reliability analysis; probability; uplift; system reliability;

   Sammanfattning : Risk management is increasingly used in dam safety and includes risk analysis, risk evaluation and risk reduction. Structural Reliability Analysis (SRA) is a probabilistic methodology that may be used in the risk assessment process. LÄS MER

5. 4. Thermo-Acoustic Properties in Combustion Chambers

   Författare :Guillaume Jourdain; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mode Stability Analysis; Computational Aeroacoustics; Screech mode; Arnoldi s Method; Buzz mode; Afterburner; Gas turbine combustor; Combustion instabilities;

   Sammanfattning : Design and analysis methods for gas turbine combustors or afterburners have to be improved in particular regarding the prediction of combustion instabilites. A methodology, which combines the use of a linearized flow solver and an Arnoldi algorithm performing the eigenmode extraction procedure, resolves eigenmodes which are candidates to these instabilities. LÄS MER

7. 5. Wind Power - Added Value for Network Operation

   Författare :Nayeem Ullah; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; torsional oscillation; reactive power ancillary service; voltage stability; power system simulator.; STATCOM; non-minimum phase system; Variable speed wind turbine; frequency control; sensitivity analysis; transient stability; small-signal stability;

   Sammanfattning : This dissertation deals with the investigation on different value added properties of variable speed wind turbines (VSWT) that stem from the flexible controllability of converter interfaced wind turbines (WT). Improvements in voltage and transient stability of a nearby grid, small-signal stability improvement on the power system, frequency control support for the network operation, as well as thetechnical and the economic issues related to the reactive power ancillary service provision, are among the issues covered. LÄS MER