Sökning: "Resonance frequency"

Visar resultat 26 - 30 av 313 avhandlingar innehållade orden Resonance frequency.

  1. 26. Assessment of Long-Term Losses in Prestressed Concrete Structures - Application for Nuclear Reactor Containments

    Författare :Peter Lundqvist; Avdelningen för Konstruktionsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; KstrConcrete; Nuclear reactor containments; prestressed concrete; prestress losses; bonded tendons; creep; shrinkage; relaxation; prediction models; resonance frequency; acoustoelasticity.;

    Sammanfattning : Most nuclear reactors, both in Sweden and worldwide, are enclosed by a prestressed concrete containment. The main purpose of the containment is to prevent any radioactive discharge to the environment in the event of a major internal accident. LÄS MER

  3. 27. Aspects on Dynamic Power Flow Controllers and Related Devices for Increased Flexibility in Electric Power Systems

    Författare :Nicklas Johansson; Hans-Peter Nee; Göran Andersson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Adaptive Control; Controlled Series Compensator; Dynamic Power Flow Controller; Frequency Scanning; Phase-Shifting Transformer; Power Controller Plane; Power Flow Control; Power Oscillation Damping; Subsynchronous Resonance; Thyristor Controlled Series Compensator; Thyristor Switched Series Compensator; Transient Stability; Electrical engineering; Elektroteknik;

    Sammanfattning : This thesis studies different aspects of Flexible AC Transmission System (FACTS) devices which are used to improve the power transfer capability and increase the controllability in electric power systems. In the thesis, different aspects on the usage and control of Dynamic Power Flow Controllers (DPFC) and related FACTS devices are studied. LÄS MER

  4. 28. Voltage Transients in the Field Winding of Salient Pole Wound Synchronous Machines : Implications from fast switching power electronics

    Författare :Roberto Felicetti; Urban Lundin; Jon Kjellin; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; apparent resistance; cable modeling; current control; transmission line model; eddy currents; field winding; frequency analysis response; Fourier Transform; impedance mismatch; main inductance; overvoltage; parasitic capacitance; partial discharge; quality factor; ringing; slew rate; stray inductance; voltage gradient; winding resonance frequency;

    Sammanfattning : Wound Field Synchronous Generators provide more than 95% of the electricity need worldwide. Their primacy in electricity production is due to ease of voltage regulation, performed by simply adjusting the direct current intensity in their rotor winding. LÄS MER

  5. 29. Acoustical Measurements of Material Nonlinearity and Nonequilibrium Recovery

    Författare :Kristian Haller; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear acoustics; nondestructive testing; activation density; slow dynamics; nonequilibrium recovery; resonance frequency; nonlinear wave modulation spectroscopy; harmonic generation; trapped modes; open resonator; sweep rate; constant strain sweep;

    Sammanfattning : A damaged material or a material with non perfect atomic geometry, dislocations or cracks, exhibits two types of characteristic responses to acoustic excitations. First is the fast nonlinear dynamics response that is present as long as the material is excited. As soon as the excitation stops the response disappear. LÄS MER

  7. 30. Run-Up Transient Analysis for Salient Pole Wound Field Synchronous Motors : Field winding and power electronics implications for a smoother and cooler asynchronous start

    Författare :Roberto Felicetti; Urban Lundin; Andreas Binder; Uppsala universitet; []
    Nyckelord :apparent resistance; cable modeling; current control; transmission line model; eddy currents; field winding; frequency analysis response; Fourier Transform; impedance mismatch; main inductance; overvoltage; parasitic capacitance; partial discharge; quality factor; ringing; slew rate; stray inductance; voltage gradient; winding resonance frequency; asynchronous start; run-up; torque ripple; reluctance torque; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Salient Pole Wound Field Synchronous Machines have better efficiency at full load than asynchronous machines of the same capability. Moreover, where asynchronous machines need inherently to draw a magnetizing current from the grid, Salient Pole Wound Field Synchronous Machines can work efficiently at unity power factor. LÄS MER