Sökning: "electromechanical oscillations"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden electromechanical oscillations.

1. 1. Non-intrusive Methods for Mode Estimation in Power Systems using Synchrophasors

   Författare :Vedran Peric; Luigi Vanfretti; Xavier Bombois; Cristian Rojas; Mani V. Venkatasubramanian; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Synchrophasors; Phasor measurement units; system identification; mode estimation; electromechanical oscillations; prediction error; signal selection; experiment design; probing; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Real-time monitoring of electromechanical oscillations is of great significance for power system operators; to this aim, software solutions (algorithms) that use synchrophasor measurements have been developed for this purpose. This thesis investigates different approaches for improving mode estimation process by offering new methods and deepening the understanding of different stages in the mode estimation process. LÄS MER

3. 2. Electromechanical Instability in Suspended Nanowire-Based NEMS

   Författare :Fabio Santandrea; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NEMS; Shuttle instability; Coulomb blockade; Carbon Nanotubes; Electronic Transport; Nonlinear Dynamics;

   Sammanfattning : "Nanoelectromechanical systems'' (NEMS) are a class of nanometer-sized mechanical structures coupled to electronic device of comparable dimensions. Their peculiar features make them interesting both from the technological and fundamental research viewpoints. LÄS MER

4. 3. Electromechanical Phenomena in Superconducting and Normal Nanostructures

   Författare :Milton Eduardo Peña-Aza; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanoelectromechanical systems; nanoelectromechanical Josephson junctions; metallic carbon nanotubes; ground-state cooling; chaos;

   Sammanfattning : This thesis summarizes a series of theoretical studies on the electromechanical properties of nanostructures made of superconducting and/or metallic elements. The first part of the work is devoted to the analysis of the interactions between the electronic and mechanical degrees of freedom in suspended nanowires. LÄS MER

5. 4. Self Oscillations and Cooling of Carbon Based NEMS Devices

   Författare :Anders Nordenfelt; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nano electro-mechanics; carbon nanotubes;

   Sammanfattning : We investigate the electromechanical properties of a number of system geometries featuring a doubly clamped Carbon Nanotube or Graphene sheet with a deflection sensitive resistance and an electronic feedback in the form of a Lorentz force or an electrostatic attraction. The nanotube is subjected to a constant current- or voltage bias and it is shown that when the electro-mechanical coupling exceeds a certain critical value the system becomes unstable to self-excitations of the mechanical vibrations accompanied by oscillations in the voltage drop and current through the nanotube. LÄS MER

7. 5. Control of Energy Storage Equipped Shunt-connected Converter for Electric Power System Stability Enhancement

   Författare :Mebtu Bihonegn Beza; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; transient stability.; energy storage; recursive least square RLS ; electromechanical oscillation; Signal estimation technique; static synchronous compensator; power oscillation damping POD ;

   Sammanfattning : Flexible AC Transmission System (FACTS) controllers, both in shunt and series configuration, are widely used in the power system for power flow control, to increase the loading capability of an existing line and to increase the security of the system by enhancing its transient stability. Among the FACTS controllers family, the Static Synchronous Compensator (STATCOM) is a key device for the reinforcement of the stability in an AC power system. LÄS MER