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Design of a robust speed and position sensorless decoupled P-Q controlled doubly-fed induction generator for variable-speed wind energy applicationsGogas, Kyriakos. January 2007 (has links)
Wind energy is a relatively young but rapidly expanding industry. In order for wind generation to be cost effective, it must produce energy at a minimum cost per dollar of investment. Performance characteristics such as power output versus wind speed must be optimized in order to compete with other energy sources. Also, if the utility uses wind power for a part of its generation, the output power of these turbines must have the same high quality and reliability when it enters the utility grid. The ability to vary operating speed is important in wind generation because it allows for an optimization of the transfer of power from the wind to the turbine shaft. Doubly-fed induction generators (DFIG) are an interesting solution for variable-speed systems with limited variable speed range, and are typically used in wind energy conversion systems. / The objectives of this thesis are to implement a decoupled P-Q control of a DFIG that does not rely on mechanical sensors and to design a speed and position sensorless algorithm that is robust to variations of the values of the machine parameters. The sensorless DFIG control algorithm presented in this thesis is based on a modified phasedlock loop with an improved positioning algorithm. With the measured stator voltages, stator and rotor currents, the speed and position of the DFIG are estimated. The speed is estimated independent of machine parameters, which results in a significant improvement in speed control robustness to parameter variations. In addition, the algorithm avoids using differentiation, which significantly improves its immunity to noise and does not require the measurement of the rotor voltages. Also, it is shown that the positioning algorithm has an improved operation in generator mode. Although the accuracy of the positioning algorithm is depended on machine parameters; it is shown with the designed controller that the P-Q decoupled control is robust to changes of machine parameters. Theoretical and simulation results are validated on an experimental setup.
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Mesh generation and equipotential plotting in 3-DForghani, Behzad. January 1981 (has links)
No description available.
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Position-sensorless control of permanent magnet synchronous machines over wide speed rangeChi, Song. January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 152-158).
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Power and mutualism in Japanese supply networksAhmadjian, Christina Linn. January 1995 (has links)
Thesis (Ph. D.)--University of California at Berkeley, 1995.
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Adaptive sliding mode observer and loss minimization for sensorless field orientation control of induction machineLi, Jingchuan. January 2005 (has links)
Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 120-126).
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Drehgeberlose Lageidentifikation bei elektrischen Asynchronmaschinen /Juliet, Jorge. January 2006 (has links)
Wuppertal, Universiẗat, Thesis (doctoral).
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Design of tapered and straight stator pole switched reluctance machinesSitsha, Lizo M. M. 04 1900 (has links)
Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: This thesis deals with the design and optimisation of medium power traction switched
reluctance machines with tapered and straight stator poles. Only the prototype of the
tapered stator pole machine is constructed and evaluated in this study.
A non-commercial finite element package is used in the design and optimisation
of the machines. The finite element method is applied directly in the optimisation
procedure to optimise the design of the machines in multi-dimensions. The lumped
circuit analysis method is used only for the purpose of verifying some of the finite
element calculated. It is not used in the optimisation procedure.
The performance characteristics of the tapered and straight stator pole machines
are compared and discussed and the tapered stator pole machine is found to have
better torque performance. Also the calculated and measured static torque versus rotor
position characteristics of the tapered stator pole machine are compared and discussed. / AFRIKAANSE OPSOMMING: Die tesis beskryf die ontwerp en optimering van medium drywing trekkrag geskakelde
reluktansie masjiene met tapse en reguit stator pole. Slegs 'n prototipe van die tapse
stator pool masjien is gebou en geëvalueer.
Die masjiene is ontwerp en geoptimeer met behulp van 'n nie-kommersiële eindige
element metode pakket. Die eindige element metode is direk in die optimerings algoritme
gebruik vir die optimering van die masjiene in multi-dimensies. Die gekonsentreede
parameter stroombaananalise is slegs gebruik om sommige van die eindige
element berekenings te verifeer.
Die vermoës van die tapse en reguit stator pool masjiene is vergelyk en bespreek.
Die resultate toon dat die tapse stator pool masjien se draaimoment vermoë beter is as
die van die reguit stator pool masjien. Die berekende en gemete statiese draaimoment
teenoor rotorposisie van die tapse stator pool masjien is ook vergelyk en bespreek.
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Some design aspects of the multi flux barrier rotor reluctance synchronous machineBomela, Xola B. 12 1900 (has links)
Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: This thesis deals with different design aspects of the multi-flux barrier rotor of the reluctance synchronous
machine (RSM). The effect of the different designs on the performance of the RSM is
investigated by means of two-dimensional finite element analysis. The finite element analysis is also
directly used in the optimum design of the rotor of the RSM. The importance of the use of the finite
element analysis in the design and performance calculations of the RSM is illustrated in this thesis.
The design aspects of the RSM which are focussed on in this thesis are, amongst other things,
the chording of the stator winding, the skewing of the rotor and the ratio of the number of rotor flux
barriers to the number of stator slots of the RSM. The effects of these design aspects on the average
torque and torque ripple of the RSM are investigated and general design directives are given. The
occurrence of flux pulsations in the stator teeth and rotor iron segments of the RSM are also studied
to some extent.
The finite element optimum design of a4-pole RSM-rotor with a high number of flux barriers is
described in the thesis. This optimum designed rotor is built and the RSM with this rotor is tested
in the laboratory. Its calculated and measured performances are studied and compared with a conventional,
low number rotor flux barrier RSM. It is found, amongst other things, that the RSM with
the high number of rotor flux barriers has a slightly higher average torque with a significantly lower
torque ripple. / AFRIKAANSE OPSOMMING: Hierdie tesis handeloor verskillende ontwerp-aspekte van die reluktansie sinchroonmasjien (RSM)
met 'n multi-vloedversperringsrotor. Die effek van die verskillende ontwerpe op die vermoë van die
RSM is met behulp van twee-dimensionele eindige element analise ondersoek. Die eindige element
analise is ook direk in die optimum ontwerp van die rotor van die RSM gebruik. Die belangrikheid
van die gebruik van die eindige element analise in die ontwerp en vermoë-berekening van die RSM
word in die tesis geïllustreer.
Die ontwerp-aspekte van die RSM waarop in hierdie tesis gefokus word, is onder andere die spoelsteekverkorting
van die statorwikkeling, die skuinsing van die rotor en die verhouding van die
getal rotor-vloedverperrings tot die getal statorgIeuwe van die RSM. Die effek van hierdie ontwerpaspekte
op die gemiddelde draaimoment en draaimoment-rimpel van die RSM word ondersoek en
algemene riglyne vir die ontwerp van die RSM word gegee. Die voorkoms van vloedpulsasies in die
statortande en rotor yster segmente van die RSM word ook deels ondersoek.
Die eindige element optimum ontwerp van 'n 4-pool RSM-rotor met 'n hoe getal vloedversperrings
word in die tesis beskryf. Hierdie optimum ontwerpte rotor is gebou en die RSM met hierdie rotor is
in die laboratorium getoets. Die berekende en gemete vermoë is bestudeer en vergelyk met die vermoë
van 'n RSM met 'n konvensionele, lae getal vloedversperrings rotor. Dit is onder andere gevind
dat die RSM met die hoë getal rotor-vloedversperrings 'n effens hoër gemiddelde draaimoment het
met 'n behuidende laer draaimoment-rimpel.
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Critical evaluation of a position sensorless control technique for the reluctance synchronous machine driveSmuts, Johan L. (Johan Leodolf) 03 1900 (has links)
Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The aim of this study is to critically evaluate the voltage injection position sensorless
control technique as applied to the reluctance synchronous machine (RSM) drive and
to implement the technique on a 5.5 kW RSM and a 110 kW RSM. The technique is
evaluated by using an accurate mathematical model of the RSM in a simulation
package, called Simuwin. The negative effects that cross-magnetisation and the
slotted air-gap have on the technique are intensively investigated. It was showed that
these effects can cause an error in the position estimation of up to 30°. The
TMS320F240 DSP was used as the controller for the RSM drives to implement the
position sensorless control technique. Measurements on both RSM drives confirm the
simulated results. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om die spannings-injeksie posisie sensorlose beheer
tegniek soos toegepas op die reluktansie sinchroon masjien (RSM) aandryfstelsel,
krities te evalueer en te implementeer op 'n 5.5 kW RSM en op 'n 110 kW RSM. Die
tegniek is geevalueer deur 'n akkurate wiskundige model van die RSM saam te stel en
die model te gebruik in 'n simulasie pakket, genaamd Simuwin. Daar is veral klem
gele op die negatiewe invloed wat kruis-magnetisering en 'n gegleufde lug-spleet op
die tegniek het. Dit is bewys dat hierdie eienskappe van die RSM 'n fout in die posisie
afskatting van tot 30° kan veroorsaak. Die TMS320F240 DSP is gebruik as beheerder
vir die RSM aandryfstelsels om sodoende posisie sensorlose beheer op altwee
masjiene toe te pas. Metings op albei stelsels bevestig die simulasies.
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Proteção Diferencial de Transformadores Usando a Transformada Wavelet /Silva, Paulo Henrique Gonçalves Leonel da. January 2014 (has links)
Orientador: José Roberto Sanches Mantovani / Banca: Fábio Bertequini Leão / Banca: José Carlos de Melo Vieira Junior / Resumo: Neste trabalho apresenta-se um algoritmo numérico de proteção diferencial de transformadores de potência. Neste algoritmo tem-se como principal objetivo a busca por uma eficiente discriminação entre correntes de faltas e correntes de magnetização, também conhecidas como correntes de inrush, que podem provocar a atuação indevida do relé diferencial. A transformada wavelet é utilizada para discriminar correntes de faltas de correntes de inrush utilizando o princípio de conservação de energia presente na análise multirresolução para esse tipo de transformada. O algoritmo numérico foi desenvolvido no MATLAB e a simulação do circuito elétrico usado como teste é realizada em software ATP/EMTP pela sua já consolidada utilização e confiabilidade de resultados quando se dispõe de dados técnicos reais de sistemas elétricos de potência. As simulações e resultados apresentados indicam que a técnica desenvolvida mostra-se eficiente de acordo com os comportamentos esperados de relés de proteção típicos / Abstract: In this work it is presented a numerical algorithm for transformer differential protection. The principal objective of this algorithm is the search of an efficient distinction between fault currents and magnetization currents, also known by inrush currents that can induce false tripping of differential relays. The wavelet transform is used to discern fault currents from inrush currents, using the energy conservation principle that is available in this kind of transform. The numerical algorithm was developed in the software MATLAB and the electric circuit, used as a test, is simulated in software ATP/EMTP due to its already consolidated use and reliability of results when real technical data from power electric systems are available. The presented simulations and results indicates that the developed technique is shown efficient according to typical protection relay behaviours / Mestre
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