Search for dissertations about: "voltage instability"

Showing result 16 - 20 of 39 swedish dissertations containing the words voltage instability.

  2. 16. Electronic Control of Flexural Nanowire Vibrations

    Author : Fabio Santandrea; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nanoelectromechanical systems; Carbon nanotubes; Coulomb blockade; Shuttle instability; Ground-state cooling;

    Abstract : “Nanoelectromechanical systems” (NEMS) are nanometer-sized mechanical structures coupled to electronic devices of comparable size. The coupling between mechanical and electronic degrees of freedom, combined with their mesoscopic size, provide these systemswith some unique properties that make them interesting from both the fundamental and technological point of view. READ MORE

  4. 17. The Electrochemistry of LiNi0.5-xMn1.5+xO4-δ in Li-ion Batteries : Structure, Side-reactions and Cross-talk

    Author : Burak Aktekin; Kristina Edström; Daniel Brandell; Wolfgang Zipprich; Fernanda Lodi Marzano; Christian Masquelier; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; LNMO; High-voltage spinel; FEC; Cross-talk; Cation ordering; Oxygen deficiency; Anionic redox; Chemistry with specialization in Inorganic Chemistry; Kemi med inriktning mot oorganisk kemi;

    Abstract : The use of Li-ion batteries in portable electronic products is today widespread and on-going research is extensively dedicated to improve their performance and energy density for use in electric vehicles. The largest contribution to the overall cell weight comes from the positive electrode material, and improvements regarding this component thereby render a high potential for the development of these types of batteries. READ MORE

  5. 18. Transport Properties of Superconducting d-wave junctions

    Author : Tomas Löfwander; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : At surfaces and interfaces of d-wave superconductors, quasiparticle bound states with zero energy, midgap states (MGS), are necessarily formed as a consequence of the sign change of the d-wave order parameter upon 90° rotation. The MGS can never exist at s-wave superconductor surfaces and are therefore true fingerprints of unconventional superconductivity. READ MORE

  6. 19. On the Analysis of DC Network Dynamics of VSC-based HVDC Systems

    Author : Gustavo Pinares; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Frequency Domain Analysis; VSC Admittance; Eigenvalue Analysis; DC Grid Impendance; DC Grid Resonance; VSC; HVDC; DC Side Dynamics;

    Abstract : In this thesis, the dc network dynamics of VSC-HVDC systems is investigated through eigenvalue and frequency domain analysis. The eigenvalue analysis has been used to identify the factors that have an impact on the system stability. READ MORE

  7. 20. On Control of Back-to-Back Converters and Sensorless Induction Machine Drives

    Author : Rolf Ottersten; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; active filtering; flux estimation; sensorless control; induction motor; back-to-back converter; pulsewidth-modulated rectifier; virtual flux; vector current control;

    Abstract : This thesis focuses on design and analysis of the control system structure for back-to-back converter squirrel-cage induction machine drives. Particularly, sensorless control of induction machines, meaning vector control without a mechanical shaft sensor, and vector control of pulsewidth-modulated (PWM) rectifiers are considered. READ MORE