Sökning: "Frequency-domain analysis"

Visar resultat 1 - 5 av 102 avhandlingar innehållade orden Frequency-domain analysis.

  1. 1. On the Frequency Domain Analysis of Nonlinear Systems

    Författare :Karin Ståhl; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Frequency domain; Nonlinear systems; Oscillations; Volterra series;

    Sammanfattning : In this report we study how the Volterra series description of nonlinear systems can be applied to some different problems.We study oscillations in nonlinear systems. LÄS MER

  3. 2. Fast Numerical Techniques for Electromagnetic Problems in Frequency Domain

    Författare :Martin Nilsson; Per Lötstedt; Abderrahmane Bendali; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fast Multipole Method; Minimal Residual Interpolation; Sparse Approximate Inverse preconditioning; Method of Moments; fast solvers; iterative methods; multiple right-hand sides; error analysis; Numerical Analysis; Numerisk analys;

    Sammanfattning : The Method of Moments is a numerical technique for solving electromagnetic problems with integral equations. The method discretizes a surface in three dimensions, which reduces the dimension of the problem with one. A drawback of the method is that it yields a dense system of linear equations. LÄS MER

  4. 3. Analysis of VSC-based HVDC systems

    Författare :Georgios Stamatiou; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HVDC; MMC; MTDC; Poor damping; Symbolic eigenvalue expressions; Droop control; Passivity Analysis; Net damping; Frequency Domain Analysis; VSC;

    Sammanfattning : The main objective of this thesis is to perform stability and control studies in the area of VSC-HVDC systems. A major part of the investigation focuses on the development of procedures, whose aim is to understand, explain and avoid poorly-damped conditions or instability that may appear due to dc-side resonances, which stem from the interaction of converters and passive elements in such systems. LÄS MER

  5. 4. Hybrid Methods for Computational Electromagnetics in Frequency Domain

    Författare :Stefan Hagdahl; Björn Engquist; Lars Pettersson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Maxwell s equations; Geometrical Theory of Diffraction; Smooth Surface Diffraction; Boundary Element Method; Hybrid methods; Electromagnetic Scattering; Numerical analysis; Numerisk analys;

    Sammanfattning : In this thesis we study hybrid numerical methods to be used in computational electromagnetics. The purpose is to address a wide frequency range relative to a given geometry. We also focus on efficient and robust numerical algorithms for computing the so called Smooth Surface Diffraction predicted by Geometrical Theory of Diffraction (GTD). LÄS MER

  7. 5. Iterative solution of Maxwell's equations in frequency domain

    Författare :Martin Nilsson; Per Lötstedt; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical Analysis; Numerisk analys;

    Sammanfattning : We have developed an iterative solver for the Moment Method. It computes a matrix–vector product with the multilevel Fast Multipole Method, which makes the method scale with the number of unknowns. The iterative solver is of Block Quasi-Minimum Residual type and can handle several right-hand sides at once. LÄS MER