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Dynamic Analysis of Harmonics in Electrical Systems

Möllerstedt, Erik LU (2000) In PhD Theses TFRT-1060.
Abstract
Frequency domain analysis and design of power systems is complicated in the presence of harmonics, switching dynamics, nonlinearities, unbalances, and for systems with mixed ac/dc dynamics. The reason is that linearization of the system does not lead to a time invariant system, but a system with periodically time varying dynamics, which implies that there is coupling between different frequencies. Often one has to rely on simplifying assumptions and simulation.



The thesis uses linear time periodic (LTP) models to analyze power systems. The harmonic transfer function (HTF) for LTP systems is introduced. Using the HTF, the system can be treated as an infinitely dimensional linear time invariant system, which means that the... (More)
Frequency domain analysis and design of power systems is complicated in the presence of harmonics, switching dynamics, nonlinearities, unbalances, and for systems with mixed ac/dc dynamics. The reason is that linearization of the system does not lead to a time invariant system, but a system with periodically time varying dynamics, which implies that there is coupling between different frequencies. Often one has to rely on simplifying assumptions and simulation.



The thesis uses linear time periodic (LTP) models to analyze power systems. The harmonic transfer function (HTF) for LTP systems is introduced. Using the HTF, the system can be treated as an infinitely dimensional linear time invariant system, which means that the system, under certain convergence conditions, can be analyzed using the well developed theory for LTI systems.



The thesis contains four papers with power system applications. Paper I describes the modeling and analysis of networks including components with switching dynamics, such as diodes and thyristors. An algorithm for parameter estimation from experimental data is presented. Papers II and III treats modeling and analysis of single-phase railway systems. The modeling of the locomotives is performed in collaboration with industry. Paper IV treats analysis and control aspects of a converter for grid connection of a micro-turbine used for distributed power generation. This is a three-phase application done in collaboration with the industry. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof. Hill, David, Sydney University, Australia
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Automation, converter control, modeling, linear time periodic systems, frequency domain analysis, harmonics, power systems, small signal stability, robotics, control engineering, Automatiska system, robotteknik, reglerteknik
in
PhD Theses
volume
TFRT-1060
pages
153 pages
publisher
Department of Automatic Control, Lund Institute of Technology (LTH)
defense location
room M:a, the M-building, Lund Institute of Technology
defense date
2000-11-10 10:15
ISSN
0280-5316
language
English
LU publication?
yes
id
7f52fae0-d275-4cc5-b337-60294fc6173f (old id 40974)
date added to LUP
2007-07-31 16:30:22
date last changed
2016-09-19 08:44:58
@phdthesis{7f52fae0-d275-4cc5-b337-60294fc6173f,
  abstract     = {Frequency domain analysis and design of power systems is complicated in the presence of harmonics, switching dynamics, nonlinearities, unbalances, and for systems with mixed ac/dc dynamics. The reason is that linearization of the system does not lead to a time invariant system, but a system with periodically time varying dynamics, which implies that there is coupling between different frequencies. Often one has to rely on simplifying assumptions and simulation.<br/><br>
<br/><br>
The thesis uses linear time periodic (LTP) models to analyze power systems. The harmonic transfer function (HTF) for LTP systems is introduced. Using the HTF, the system can be treated as an infinitely dimensional linear time invariant system, which means that the system, under certain convergence conditions, can be analyzed using the well developed theory for LTI systems.<br/><br>
<br/><br>
The thesis contains four papers with power system applications. Paper I describes the modeling and analysis of networks including components with switching dynamics, such as diodes and thyristors. An algorithm for parameter estimation from experimental data is presented. Papers II and III treats modeling and analysis of single-phase railway systems. The modeling of the locomotives is performed in collaboration with industry. Paper IV treats analysis and control aspects of a converter for grid connection of a micro-turbine used for distributed power generation. This is a three-phase application done in collaboration with the industry.},
  author       = {Möllerstedt, Erik},
  issn         = {0280-5316},
  keyword      = {Automation,converter control,modeling,linear time periodic systems,frequency domain analysis,harmonics,power systems,small signal stability,robotics,control engineering,Automatiska system,robotteknik,reglerteknik},
  language     = {eng},
  pages        = {153},
  publisher    = {Department of Automatic Control, Lund Institute of Technology (LTH)},
  school       = {Lund University},
  series       = {PhD Theses},
  title        = {Dynamic Analysis of Harmonics in Electrical Systems},
  volume       = {TFRT-1060},
  year         = {2000},
}