Sökning: "frequency response analysis"

Visar resultat 1 - 5 av 342 avhandlingar innehållade orden frequency response analysis.

  1. 1. The Frequency of the Frequency : On Hydropower and Grid Frequency Control

    Författare :Linn Saarinen; Urban Lundin; Per Norrlund; Bengt Carlsson; Kjetil Uhlen; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; hydropower; frequency control; governors; power system stability; inertia; primary control; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Variations in the electricity consumption and production connected to the power system have to be balanced by active control. Hydropower is the most important balancing resource in the Nordic system, and will become even more important as the share of variable renewable energy sources increases. LÄS MER

  3. 2. Two-Dimensional Signal Root Estimation in Blind Multichannel Impact Response Analysis

    Författare :Joakim Axmon; Matematisk statistik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; forestry; Silviculture; detection of decay.; Norway spruce; X-texture mode; signal subspace enhancement; partial forward-backward averaging; ESPRIT; state-space; Prony; frequency analysis; SIMO; impact response; Modal analysis; impact excitation; forestry technology; Skogsvetenskap; skogsbruk; skogsteknik; Electrical engineering; Elektroteknik; Signal processing; Signalbehandling;

    Sammanfattning : This doctoral dissertation concerns two-dimensional frequency estimation for modal analysis of single-input multiple-output impact responses from circularly cylindrical objects. The application is within detection of internal defects in trunks of spruce. LÄS MER

  4. 3. Trapezius muscle fatigue and electromyographic frequency analysis

    Författare :Tommy Öberg; Linköpings universitet; []
    Nyckelord :EMG; Spectrum; Frequency; Fatigue; Trapezius; Myalgia; MEDICINE; MEDICIN;

    Sammanfattning : This study, comprising 6 separate articles, is concerned with different validity and reliability aspects of the electromyogram mean power frequency (MPF) as an estimator of localized musele fatigue in the trapezius muscle. A series of new, and partly controversial and problematic findings are reported. LÄS MER

  5. 4. Effect of Dielectric and Magnetic Material Characteristics on Frequency Response of Power Transformers

    Författare :Nilanga Abeywickrama; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; frequency response analysis; dielectric insulation; Complex permeability; core magnetization; finite element method; transformer diagnosis.; high frequency modelling; magnetic viscosity; silicon steel;

    Sammanfattning : Frequency response analysis (FRA) technique has become increasingly popular for the assessment of mechanicalintegrity in power transformers. This method is based on the fact that the shape of the frequency response at higher frequencies is uniquely determined by the geometrical construction of the transformer. LÄS MER

  7. 5. Modelling the transient response of windings, laminated steel coresand electromagnetic power devices by means of lumped circuits : With special reference to windings with a coaxial insulation system

    Författare :Pär Holmberg; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Transient response; frequency response; electromagnetic transient analysis; circuit modeling; eddy currents; skin effect; windings; coils; magnetic cores; cables; electric machines; rotating electric machines; transformers; Fysik; Physics; Fysik; Electricity; Esp The Study Of Transients and Discharges; elektricitetslära; ssk studiet av transienter och urladdning;

    Sammanfattning : Electromagnetic transients impinging on electromagnetic power devices - such as electric machines, transformers and reactors - can stress the design severely. Thus the magnitudes of the transients are often decisive for the design of the devices. Further, the operation of a device can be transient in itself. LÄS MER