Sökning: "weak ac systems"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden weak ac systems.

  1. 1. Modeling and Control of VSC-HVDC Links Connected to Weak AC Systems

    Författare :Lidong Zhang; Hans-Peter Nee; Alan Wood; KTH; []
    Nyckelord :Control; modeling; multivariable feedback control; HVDC; power systems; stability; subsynchronous torsional interaction; voltage-source converter; weak ac systems;

    Sammanfattning : For high-voltage direct-current (HVDC) transmission, the strength of the ac system is important for normal operation. An ac system can be considered as weak either because its impedance is high or its inertia is low. LÄS MER

  3. 2. Cooling of a Suspended Nanowire by an ac Josephson current

    Författare :Milton Eduardo Peña-Aza; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanoelectromechanical systems; nanowire; metallic carbon nanotubes; quantum ground state cooling of nanomechanical resonators; superconduting weak links; nanoelectromechanical Josephson junction;

    Sammanfattning : Nanoelectromechanical systems have been used for the exploration of the quantum limit of mechanical motion. There is hope that the quest for the quantum regime of these systems will shed light on fundamental questions in physics and lead to new quantum technologies. LÄS MER

  4. 3. Quantum mechanical effects on charge transport in two mesoscopic systems

    Författare :Gustav Sonne; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanoelectromechanical systems; NEMS; carbon nanotubes; carbon peapods; excess current; superconducting weak links; suspended carbon nanotubes; non-linear resonances;

    Sammanfattning : Carbon nanotubes are one of the most promising building blocks for the developing field of nanoelectromechanics. Due to their unique electronic and mechanical properties, these all-carbon systems have been suggested for a range of applications where one wishes to utilse the coupling between mechanical and electronic degrees of freedom on the nanometer length scale. LÄS MER

  5. 4. Dynamics of complex magnetic systems

    Författare :Kristian Jonason; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Materialvetenskap; Materials science; Teknisk materialvetenskap; Solid State Physics; fasta tillståndets fysik;

    Sammanfattning : Dynamic magnetic properties of disordered and frustrated magnetic systems have beenexperimentally investigated utilising SQUID (Superconducting Quantum Interference Device)magnetometry. The studied systems are spin glasses, reentrant ferromagnets, reentrantantiferromagnets and diluted Ising antiferromagnets. LÄS MER

  7. 5. Voltage and power stability of HVDC systems

    Författare :Denis Hau Aik Lee; KTH; []
    Nyckelord :;

    Sammanfattning : This research work had been motivated by the emergence of multiple HVDC links in close proximity within a power system area, such as those in Southem Scandinavia and Northem Europe. Such system tonfigurations, generally known as multi-infeed HVDC systems, are expected to exhibit voltage and power stability problems when one or more of the constit uent AUDC interconnections are weak. LÄS MER