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Sünter, Sedat. "A vector controlled matrix converter induction motor drive." Thesis, University of Nottingham, 1995. http://eprints.nottingham.ac.uk/12965/.
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This thesis concerns the design and construction of a closed-loop controlled matrix converter induction motor drive, using transputer parallel processors. The modulation algorithms used for the matrix converter are described. A 2.5 kW experimental matrix converter using IGBT switching devices has been constructed and tested. An analysis of the losses in the converter has been carried out and this gives good agreement with the measured losses. Two modulation algorithms, the Venturini algorithm and the scalar algorithm have been implemented in real-time on a network of parallel transputer processors. Experimental results are presented to compare the operation of these two algorithms. Open-loop constant V/F control of the matrix converter induction motor drive has been demonstrated. A controller has been designed to achieve closed-loop speed control of the drive system, employing the slip regulation technique. The experimental results under various operating conditions have verified the correct operation of both control systems. The indirect vector control technique has also been implemented. The results demonstrate the steady-state and transient performance as well as the regenerative operation of the drive system. The application of a matrix converter to a high performance induction motor servo drive rated at 2.5 kW with true four quadrant capability and minimum passive components has been demonstrated.
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Mushenya, John. "Energy efficiency analysis of converter-fed induction motors." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29301.
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Electric motor systems are the largest consumers of industrial electrical energy. As Variable Speed Drives continue to dominate various industrial processes, there is need for stakeholders to fully understand and quantify the converter-fed motor losses over a wide range of operating conditions. Such knowledge is crucial for both manufacturers and end-users in performing energy-efficiency optimizations for motor-drive applications. Although there is an increase in legislative activities, particularly in Europe, toward classification and improvement of energy efficiency of electric motor-drive systems, the available standards for quantifying the various losses are still in their early stages of development. None of these standards have yet passed through all the required phases for them to be considered full international standards, owing to a lack of consensus on many technical issues. Therefore, the need for researchers to provide feedback to the relevant standards committees cannot be over-emphasized. One of the most challenging issues in estimating the efficiency of converter-fed motors is the accurate determination of additional harmonic losses due to the PWM voltages and currents. Although the recently introduced IEC 60034-2-3 Technical Specification has proposed a method of determining these losses through experimental testing, the approach is still undergoing validation. Moreover, it only considers the rated motor frequency and voltage whereas induction motor drives are usually operated over a wide range of speed and torque. The main emphasis of the work presented in this dissertation was to develop a thorough understanding of various converter-fed induction motor losses, and hence efficiency, when fed from a 2-level Voltage Source Inverter. In particular, the dissertation provides a healthy questioning of some concepts in the proposed IEC method, with a view to providing useful feedback for improving the standard. Comparisons are also drawn between the related standards to identify areas for improvement. This study further attempts to explain some conflicting reports cited in literature regarding the nature of additional harmonic losses. The experimental results obtained by testing three induction motors demonstrate some of the technical issues associated with the determination of additional harmonic losses. To mitigate the adverse effect of varying technical skill and competence levels on efficiency test results, an automated testing procedure was developed and implemented on the 110kW test rig in the UCT Machines Lab. The test rig, which boasts of a Genesis 7i high-speed Data Acquisition System, also provides an energy-efficient platform for investigating the steadystate and dynamic characteristics of converter-fed motors. By utilizing the capability of the Data Acquisition System to segregate the fundamental and harmonic components of measured input electrical power, it was found that a PWM power supply can be used in place of a conventional Variac to estimate the sinusoidal supply efficiency of an induction motor. This is a welcome development for both laboratory and field efficiency testing applications.
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Druyts, Jan. "Control induction motor by frequency converter : Simulation electric vehicle." Thesis, Halmstad University, Energiteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-4968.
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Summary
Today we are probably on a point of change for the car industry. The last century was the century of vehicles with internal combustion engines. Fossil fuels were relative cheap, easy accessible and they have a high specific energy. The pollution and dependency on oil caused the last decade an increasing demand for alternatives. Alternatives for electric power plants and for car drives. Yet the turnover to hybrids is a fact and much research is done for pure electric vehicles. Research about the control of electric motors is by that become a hot topic.
To simulate an electric vehicle drive with an induction motor, a frequency converter is needed. This combination of motor and converter led to many possible experiments. With a few experiments already done and a broad theoretical background report this thesis provides a good bundle of information to start with further experiments. The experiments can become even broader when a flywheel is added as mass inertia momentum and a DC source on the DC-link. Both elements contribute for a better simulation of an electric motor in an electric vehicle.
What is described in this theoretical report about the combination of an induction motor and converter is only the tip of the iceberg. I had too less time to begin experimenting with the flying wheel. The DC-link voltage becomes ca. 540V. From the perspective of safety I could never work alone with the DC-link. Even with a companion it was too dangerous because the equipment of the Halmstad University is not made for such dangerous voltages. That’s why this thesis contains more theoretical background and less actual practical data.
SAMENVATTING
Momenteel bevinden we ons in een tijd van omslag. Na een eeuw waarin de brandstofmotor het transportlandschap domineerde, is er nood aan een alternatief. Fossiele brandstof zorgt voor schadelijke uitlaatgassen bij verbranding en de afhankelijkheid van andere landen voor de bevoorrading van fossiele brandstof blijft altijd een risicofactor. De eerste stap in deze verandering is gezet met de ontwikkeling van hybride wagens. De toekomst zal waarschijnlijk helemaal elektrisch worden. Daarom is het onderzoek naar de controle van elektrische motoren belangrijk.
In de universiteit van Halmstad zijn er verscheidene inductiemotoren aanwezig in het elektriciteitslabo. De doelstelling was dat ik een frequentieomvormer selecteerde, bestelde en parametreerde op basis van deze motoren. Daarnaast kreeg ik de vrijheid om een elektrische wagen te simuleren. Dit zou ik doen door een vliegwiel voor de traagheid en door een batterij na te bootsen om de DC-link te voeden. Al mijn informatie moest ik bundelen in deze thesistekst zodat het eventueel een handige bundel werd voor toekomstige studenten die willen werken met de convertor.
Ik had slechts 2 maanden de tijd om dit uit te voeren, metingen te doen en een theoretisch verslag te schrijven. Vanwege deze korte tijdspanne was het niet mogelijk het vliegwiel te implementeren. Daarnaast was de tussenkringspanning ongeveer 540V DC. Dit is zeer gevaarlijk zodat ze liever hadden dat ik de proeven met een gesimuleerde batterij liet varen. Dit verklaart enigszins waarom uitgebreide meetresultaten ontbreken en deze thesis vooral een bredere theoretische toets heeft.
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Yao, Yanmei. "Study of Induction Machines with Rotating Power Electronic Converter." Doctoral thesis, KTH, Elkraftteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-196054.
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This thesis investigates a novel induction machine topology that uses a rotating power electronic converter. Steady-state and dynamic performance of the topology is studied to understand its operational principle. Furthermore the potential of improving its efficiency and power factor is investigated. The topology is referred to as wound rotor induction machine with rotating power electronic converter (WRIM-RPEC). The WRIM-RPEC topology offers the possibility to magnetize the induction machine from the rotor side by introducing a reactive voltage in the rotor. Thus, the power factor of the machine can be improved. Constant speed variable load operation can be achieved by setting the frequency of the introduced voltage. Two options of rotor winding and converter configuration in the WRIM-RPEC system are investigated. The wound rotor windings can either be open-ended and fed by a three-phase back-to-back converter or Y-connected and fed by a single three-phase converter. The dc-link in both converter configurations contains only a floating capacitor. These two configurations give different dc-link voltages at the same torque and speed. Two analytical steady-state models of the topology are developed in this thesis. The first model can be used to analyze the operating condition of the motor at specific speed and torque. Particularly, the operating range of speed and torque of the topology is investigated. The second model is used to analyze variable power factor operation, including unity power factor operation. Analytical calculations and measurements are carried out on a 4-pole, 1.8kW induction machine and the results are compared. A dynamic mathematic model is then developed for the WRIM-RPEC system for the back-to-back converter configuration. The mathematic model is then applied in Matlab/Simulink to study the dynamic performance of the system including starting, loading and phase-shifting. The simulation results are compared with measurements on the 4-pole, 1.8kW induction machine. Moreover, the simulation model using the existing Simulink blocks are studied to compare with the results obtained from the mathematic model. Furthermore, the dynamic performance of the WRIM-RPEC system with the single converter configuration is investigated. In addition, harmonic spectra analysis is conducted for the stator and rotor currents. In the last part of the thesis, efficiency improvement is investigated on the 4-pole induction machine when it is assumed to drive a pump load. It is shown that the efficiency can be further improved by decreasing the rotor resistance. Due to space constraints it is however difficult to decrease the rotor resistance in a 4-pole induction machine. An investigation is thus carried out on a standard 12-pole, 17.5kW squirrel-cage induction machine with inherent low power factor. The cage rotor is redesigned to a wound rotor to enable the connection of converter to the rotor windings. An analytical model is developed to design the wound rotor induction machine. The machine performance from calculations is then compared with FEM simulations with good agreement. The analytical model is further used to design several WRIMs with different dimensions and rotor slot numbers. Power factor and efficiency improvement is then explored for these WRIMs. A promising efficiency increase of 6.8% is shown to be achievable.QC 20161111
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Chikwanda, Herbert Simbarashe. "The naturally commutated, converter-fed, variable speed induction machine drive." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/47805.
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Lei, Ting. "Doubly-fed induction generator wind turbine modelling, control and reliability." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/doublyfed-induction-generator-wind-turbine-modelling-control-and-reliability(2ceb051a-a6fb-43e6-be40-a5023dae4bea).html.
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The trend of future wind farms moving further offshore requires much higher reliability for each wind turbine in order to reduce maintenance cost. The drive-train system and power electronic converter system have been identified as critical sub-assemblies that are subject to higher failure rates than the other sub-assemblies in a wind turbine. Modern condition monitoring techniques may help schedule the maintenance and reduce downtime. However, when it comes to offshore wind turbines, it is more crucial to reduce the failure rates (or reduce the stresses) for the wind turbines during operation since the harsh weather and a frequently inaccessible environment will dramatically reduce their availability once a failure happens. This research examines the mechanical, electrical and thermal stresses in the sub-assemblies of a doubly-fed induction generator (DFIG) wind turbine and how to reduce them by improved control strategies. The DFIG control system (the rotor-side and the grid-side converter control) as well as the wind turbine control system are well established. The interactions of these control systems have been investigated. This research examines several further strategies to reduce the mechanical and electrical stresses. The control system's coordination with the protection schemes (crowbar and dc-chopper) during a grid fault is presented as well. An electro-thermal model of the power converter has been developed to integrate with the DFIG wind turbine model, for the evaluation of the thermal stresses under different operating states and control schemes. The main contributions of this thesis are twofold. A first contribution is made by providing all the control loops with well-tuned controllers in a more integrated methodology. The dynamics of these controllers are determined from their mathematical models to minimize the interference between different control-loops and also to reduce the electrical transients. This thesis proposes a coordination strategy for the damping control, pitch control and crowbar protection which significantly reduces the mechanical oscillations. On the other hand, an integrated model of the wind turbine and converter electro-thermal system is established that can illustrate the performance integration with different control strategies.
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Wyllie, Peter Bruce. "Electrothermal modelling for doubly fed induction generator converter reliability in wind power." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/10902/.
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Increased reliance upon renewable energy sources, chiefly wind, places a growing emphasis on the reliability of the technology used in Wind Turbines. The current Wind Turbine fleet is dominated by the Doubly Fed Induction Machine WT, which utilises a partially rated power electronic converter to vary the speed of the rotor and thus ensure the maximum energy capture available from the wind. This converter is associated with a significant percentage of WT failures. This thesis examines the low frequency temperature cycling occurring in one half of the back to back converter which results in a high failure rate of the rotor side converter as compared to the grid side converter. To this end a MATLAB/PLECS model was constructed to demonstrate the temperature cycling occurring in a 2.5MW DFIG WT. Lifetime of the semiconductor devices was extrapolated. An adaptation to the standard Maximum Power Point Tracking control method was suggested in which the lowest operating frequencies (less than 2.33Hz) were avoided. In doing so, lifetime was observed to increase at a minor cost to energy yield from the WT.
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Chileshe, C. M. "A converter compensator for power factor control in 3-phase induction machines." Thesis, Aston University, 1996. http://publications.aston.ac.uk/12244/.
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The advent of the harmonic neutralised shunt Converter Compensator as a practical means of reactive power compensation in power transmission systems has cleared ground for wider application of this type of equipment. An experimental 24-pulse voltage sourced convector has been successfully applied in controlling the terminal power factor of a 1.5kW, 240V three phase cage rotor induction motor, whose winding has been used in place of the usual phase shifting transformers. To achieve this, modifications have been made to the conventional stator winding of the induction machine. These include an unconventional phase spread and facilitation of compensator connections to selected tapping points between stator coils to give a three phase winding with a twelve phase connection to the twenty four pulse converter. Theoretical and experimental assessments of the impact of these modifications and attachment of the compensator have shown that there is a slight reduction in the torque developed at a given slip and in the combined system efficiency. There is also an increase in the noise level, also a consequence of the harmonics. The stator leakage inductance gave inadequate coupling reactance between the converter and the effective voltage source, necessitating the use of external inductors in each of the twelve phases. The terminal power factor is fully controllable when the induction machine is used either as a motor or as a generator.
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Fjällström, Emil. "Impact of Converter Modulation Strategies on the Losses in a Traction Motor." Thesis, KTH, Elektrisk energiomvandling, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-163530.
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With an increased demand on high-efficiency electrical machines in traction applications, better understanding in the losses induced by the converter is needed. The harmonic losses from the converter are non-negligible part of the total losses in an induction machine, and these harmonic losses have been studied here with a focus on iron, skin-effect and proximity losses. The main goal of the thesis is to advise how the modulation method can be changed to lower these time harmonic losses in an induction machine. A model of the induction machine was created in the FEM(Finite Element Method) software FLUX. The iron, the proximity and the skin-effect losses were simulated in the FLUX model with different modulation method to analyse the time harmonic losses due to respective phenomena. The modulation method at higher operation is square-wave modulation, this is due to that maximum fundamental voltage has been reached. At lower operation, pulse width modulation is used, and the switching frequency can be increased to lower the time harmonics losses in the motor. The iron losses simulated in FLUX show that the losses increase with frequency even if the motor enters flux weakening operation at higher frequencies. The proximity phenomena gives rise to a distinct increase of resistive losses in the conductor closest to the air gap in the stator winding. The skin-effect phenomena affects the losses at square-wave modulation of high frequencies mostly as the time harmonics are larger and of low order.Med en ökad efterfrågan på högeffektiva elektriska maskiner i traktionsapplikationer, måste man ha en högre förståelse i de förluster som induceras av frekvensomvandlaren. Förlusterna från frekvensomvandlaren är en icke försumbar del av de totala förlusterna i induktionsmaskinen. Förlusterna har här analyserats med fokus på järn-, skineffekt- och proximityförluster. Huvudsyftet med examensarbetet är att ge råd i hur moduleringsmetoden kan ändras för att sänka övertonsförlusterna i en induktionsmaskin. En modell av induktionsmaskinen skapades i FEM(Finita Elementmetoden) mjukvaran FLUX. Järn-, proximity- och skineffektförlusterna simulerades i FLUX-modellen med olika moduleringsmetoder för att analysera övertonsförluster på grund av respektive fenomen. Moduleringsmetoden vid högre drift är fyrkantmodulering, det är på grund av att maximal fundamental spänning har uppnåtts. Vid lägre drift har pulsbreddsmodulering använts och switchfrekvensen kan ökas för att sänka övertonersförlusterna i motorn. Järnförlusterna som simulerades i FLUX-modellen visar att förlusterna ökar med frekvensen även när motorn utsatts för fältförsvagning vid högre frekvensker. Proximityfenomenet ger upphov till en tydlig ökning av resistiva förluster i ledaren närmast luftgapet i statorlindningen. Skineffektfenomenet påverkar förlusterna på fyrkantsmoduleringen av höga frekvenser, mest på grund av att övertonerna är större och av låg ordning.
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Cheng, Siwei. "Utilizing the connected power electronic converter for improved condition monitoring of induction motors and claw-pole generators." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43638.
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This dissertation proposes several simple, robust, and non-intrusive condition monitoring methods for induction motors fed by closed-loop inverters and claw-pole generators with built-in rectifiers. While the flexible energy forms synthesized by power electronic converters greatly enhance the performance and expand the operating region of induction motors and claw-pole generators, they also significantly alter the fault behavior of these electric machines and complicate the fault detection and protection. In this dissertation, special characteristics of the connected closed-loop inverter and rectifier have been thoroughly analyzed, with particular interest in their impact on fault behaviors of the induction motor and the claw-pole generator. Based on the findings obtained from the theoretical and experimental analysis, several sensorless thermal, mechanical, and insulation monitoring methods are proposed by smartly utilizing special features and capabilities of the connected power electronic converter.
A simple and sensitive stator turn-fault detector is proposed for induction motors fed by closed-loop inverter. In addition, a stator thermal monitoring method based on active DC current injection and direct voltage estimation is also proposed to prevent the closed-loop controlled induction motors from thermally overloading. The performance of both methods is demonstrated by extensive experimental results.
Methods to detect serpentine belt slip, serpentine belt defect, rotor eccentricity have been proposed for claw-pole generators using only the available electric sensor information. Methods to detect and protect stator turn faults in claw-pole generators are also presented in this dissertation. Lastly, a novel method to detect the generalized bearing roughness fault is proposed. All the proposed condition monitoring techniques have been validated by experimental results.
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Gori, Paul-Antoine. "Transmission dynamique d'énergie par induction : application au véhicule électrique." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC063/document.
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L’autonomie limitée du véhicule électrique est le premier frein au développement du marché de l’électrique. La charge inductive dynamique répond à ce problème, en offrant de charger son véhicule en roulant. La principale difficulté est de gérer les variations importantes du couplage magnétique lors du déplacement du véhicule, et ce pendant le transfert de puissance. Une précédente thèse dans l’équipe de recherche sur un prototype de 3 kW avait abouti au concept de recopie de tension, qui stabilise la tension en sortie du coupleur malgré la variation de couplage, et facilite notablement la conception du convertisseur DC/DC faisant interface avec la batterie. La thèse présentée ici porte sur l’adaptation du système pour fonctionner de 20 kW à 30 kW. Cette montée en puissance n’est pas évidente, du fait des importantes contraintes électriques sur les bobines du coupleur (1,4 kV sur le système de 3 kW), et du champ rayonné limité par des références normatives. Tout d’abord, nous proposons une nouvelle commande du circuit résonnant, qui permet de modifier le dimensionnement pour aboutir à des contraintes électriques plus faibles tout en conservant la recopie de tension. Ensuite, une forme de bobine en huit est étudiée pour aider à réduire le champ rayonné. Enfin, une démarche de dimensionnement est établie pour la partie électrique du système, ainsi que pour le coupleur magnétique, alliant modèle analytique et simulations à éléments finis et réduisant considérablement les temps de simulations. Les résultats de l’évaluation des performances du système dimensionné pour la haute puissance sont prometteursThe limited electric-vehicle distance range is the main reason hindering the development of the electric transportation market. Dynamic inductive charging solves this problem, offering the possibility to charge while driving. The main issue consists in handling wide magnetic coupling variations when the vehicle is moving, while charging. A previous thesis in the research team on a 3-kW prototype led to the concept of voltage copying, which stabilises the coupler output voltage despite the varying coupling, making it easier to design the DC/DC converter linking the coupler to the battery. The hereby thesis deals with adapting this system to transfer from 20 kW to 30 kW. Raising the power is no small matter, due to the high electrical constraints on the coupled coils (1.4 kV on the 3-kW system), and the radiated field, limited by standardised thresholds. Firstly, a new control of the resonating circuit is proposed, allowing to change the system design to get lower electrical constraints and maintaining voltage copying properties. Then, an eight-shape coil was investigated in order to reduce the radiated field. Finally, a design method was conceived for the electrical part of the system, as well as the magnetic coupler, using jointly analytical models and finite element simulations to reduce simulation times. Results of the evaluated performance for such a high-power system are quite promising
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Molaei, Hamid. "Control of Induction Motor Drives in the Field Weakening Region Fed by a Boost Converter." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Induction motors are usually fed by voltage source inverters. In some cases, it is necessary to increase the speed of the motor beyond the rated speed. This could be done by increasing the supply voltage (which is not always possible) or by field weakening.
Field weakening algorithms are desirable since the current and the voltage of the motor cannot exceed the rated values. However, the range of the controlled speed is limited because of the limitation of the input voltage of the inverter.
In this project, considering the limitation of current and voltage, the fundamentals of the field weakening in induction motor are reviewed. Th motor performance is evaluated under a variable range of the input DC voltage. A three-phase boost converter is used to regulate the input DC voltage of the inverter. In fact, when the requested voltage of the control algorithm is greater than the producible voltage of the inverter, the input DC voltage of the inverter is increased by the boost converter.
The performance of this drive is evaluated in terms of current, torque and speed of induction motor. Besides, the efficiency of the drive is discussed.
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Dòria, Cerezo Arnau. "Modeling, Simulation and Control of Doubly-Fed Induction Machine Controlled by Back-to-Back converter." Doctoral thesis, Universitat Politècnica de Catalunya, 2006. http://hdl.handle.net/10803/5945.
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Aquesta Tesi estudia el control d'un sistema complex, un sistema d'emmagatzement d'energia cinètica, incloent les seves especificacions de control, modelat, disseny de controladors, simulacions, muntatge i validació experimental.Primerament, s'estudia l'interconnexió i control dels sistemes electromecànics. Es presenta el formalisme Hamiltonià (PCHS) en general, i després particularitzant en els sistemes electromecànics, inclòs els sistemes d'estructura variable (VSS).
L'IDA-PBC (Interconnection and damping assignment-passivity based control) és una tècnica de control basat en els PCHS. En aquesta Tesi s'estudien el problemes que apareixen en controlar, per IDA-PBC, sortides de grau relatiu u quan el paràmetres nominals del controlador són incerts. Per evitar-los es proposa introduir una acció integral que pot ésser interpretada dins l'estructura Hamiltoniana.
En aquesta Tesi també es presenten dues modificacions que permeten millorar el rang d'aplicacions de la tècnica IDA-PBC. Primer, es demostra que el fet de descomposar la tècnica de l'IDA-PBC en deformar la funció d'energia i una injecció de fregament, redueix el conjunt de sistemes que es poden estabilitzar mitjançant aquest mètode. Per evitar aquest problema, es proposa fer simultàniament els dos passos donant lloc a l'anomenat SIDA-PBC. Per altre costat, el mètode IDA-PBC requereix el coneixement de la funció energia (o Hamiltonià). Això representa un problema perquè, en general, el punt d'equilibri depèn de paràmetres incerts. En aquest treball es desenvolupa una metodologia per seleccionar l'estructura Hamiltoniana que redueix aquesta dependència dels paràmetres. Aquesta tècnica permet millorar la robustesa dels les sortides d'ordre relatiu superior a u.
El sistema d'emmagatzement d'energia cinètica consisteix en una màquina d'inducció doblament alimentada (DFIM) amb un volant d'inèrcia, controlada pel rotor per un convertidor de potència back-to-back (B2B). L'objectiu és gestionar el flux d'energia entre la DFIM i una càrrega local connectada a la xarxa, commutant entre diferents punts de funcionament. Per això es planteja una gestió de l'energia, basada en la velocitat òptima de la DFIM.
Pel què fa al control de la DFIM, es proposa un nou esquema de control que ofereix importants avantatges, i que és considerablement més senzill que el mètode clàssic, el vector control. Aquest nou controlador permet una fàcil descomposició de les potències activa i reactiva de l'estator, i el seu control a través de les tensions de rotor. Aquest disseny s'obté aplicant el procediment que millora la robustesa de l'IDA-PBC.
S'han estudiat d'altres controladors, com el vector control clàssic. També a partir de la tècnica IDA-PBC, on l'equació en derivades parcials que apareix en aplicar el mètode es pot resoldre fixant l'energia en llaç tancat, i afegint nous termes a la matriu d'interconnexió. Per obtenir un controlador definit globalment s'afegeix un terme de fregament depenent dels estats, que desacobla la part elèctrica i mecànica del sistema. Finalment, també es prova que mitjançant el SIDA-PBC es pot modelar l'energia total (elèctrica i mecànica) de la DFIM. Tots aquest controladors han estat simulats i comparats. El controlador robust IDA-PBC s'ha validat experimentalment amb uns resultats satisfactoris.
A la Tesi també es presenta un controlador que permet el flux bidireccional de potència pel B2B. L'estudi de la dinàmica zero adverteix que les tècniques de control estàndard no garanties en l'estabilitat en ambdós direccions, i per això s'utilitza un controlador IDA-PBC. Pel disseny s'utilitza un model basat en GSSA (generalized state space averaging), on es descomposa i es trunca el sistema per determinades freqüències, i que permet expresar els objectius de control (tensió constant al bus de contínua i factor de potència unitari) com un problema de regulació. Les simulacions i els resultats experimentals validen, tant la llei de control, com les simplificacions efectuades.
Els controladors proposats i validats experimentalment són usats, finalment, per implementar la gestió de potència del sistema d'emmegatzement d'energia cinètica. Els resultats confirmen el bon comportament del sistema i dels controladors IDA-PBC proposats.
This Thesis studies a complex multidomain system, the Flywheel Energy Storage System, including the control objectives specification, modeling, control design, simulation, experimental setup assembling and experimental validation stages.
The port interconnection and control of electromechanical systems is studied. The port Hamiltonian formalism is presented in general, and particularized for generalized electromechanical systems, including variable structure systems (VSS).
Interconnection and damping assignment-passivity based control (IDA-PBC) is a well known technique for port Hamiltonian systems (PCHS). In this Thesis we point out the kind of problems that can appear in the closed-loop structure obtained by IDA-PBC methods
for relative degree one outputs, when nominal values are used in a system with uncertain parameters. To correct this, we introduce an integral control, which can be cast into the Hamiltonian framework.
This Thesis also presents two new approaches which improve the range of applicability of the IDA-PBC technique.
First, we show that the standard two-stage procedure used in IDA-PBC consisting of splitting the control action into the sum of energy-shaping and damping injection terms is not without loss of generality, and effectively reduces the set of systems that can be stabilized with IDA-PBC. To overcome this problem we suggest to carry out simultaneously both stages and refer to this variation of the method as SIDA-PBC.
Secondly, we present an improvement of the IDA-PBC technique. The IDA-PBC method requires the knowledge of the full energy (or Hamiltonian) function. This is a problem because, in general, the equilibrium point which is to be regulated depends on uncertain parameters. We show how select the target port-Hamiltonian structure so that this dependence is reduced. This new approach allows to improve the robustness for higher relative degree outputs.
The Flywheel Energy Storage System consists of a doubly-fed induction machine (DFIM), controlled through the rotor voltage by a power electronics subsystem (a back-to-back AC/AC converter (B2B)), and coupled to flywheel. The control objective is to optimally regulate the power flow between the DFIM and a local load connected to the grid, and this is achieved by commuting between different steady-state regimes. A police management based on the optimal speed for the DFIM is proposed.
In this Thesis we propose a new control scheme for the DFIM that offers significant advantages, and is considerably simpler, than the classical vector control method. This controller allows an easy decomposition of the active and reactive powers on the stator side and their regulation, acting on the rotor voltage, via stator current control. This design was obtained applying the new robust IDA-PBC procedure.
Other controllers are also designed along the dissertation. The classical vector control is studied. We also apply the classic IDA-PBC technique. It is shown that the partial differential equation that appears in this method can be circumvented by fixing the desired closed-loop total energy and adding new terms to the interconnection structure. Furthermore, to obtain a globally defined control law we introduce a state--dependent damping term that has the nice interpretation of effectively decoupling the electrical and mechanical parts of the system. This results in a globally convergent controller parameterized by two degrees of freedom. Finally, we also prove that with SIDA-PBC we can shape the total energy of the full (electrical and mechanical) dynamics of the DFIM. These different controllers (vector control, IDA-PBC, SIDA-PBC and robust IDA-PBC) are simulated and compared. The IDA-PBC robust controller is also experimentally tested and shown to work satisfactorily.
A controller able to achieve bidirectional power flow for the B2B converter is presented. Standard techniques cannot be used since it is shown that no single output yields a stable zero dynamics for power flowing both ways. The controller is computed using standard IDA-PBC techniques for a suitable generalized state space averaging truncation of the system, which transforms the control objectives, namely constant output voltage dc-bus and unity input power factor, into a regulation problem. Simulation and experimental results for the full system confirm the correctness of the simplifications introduced to obtain the controller.
The proposed and tested controllers for the DFIM and the B2B are used to implement the power management policy. These results show a good performance of the flywheel energy storage system and also validate the IDA-PBC technique, with the proposed improvements.
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Sae-Kok, Warachart. "Converter fault diagnosis and post-fault operation of a doubly-fed induction generator for a wind turbine." Thesis, University of Strathclyde, 2008. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21980.
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Wind energy has become one of the most important alternative energy resources because of the global warming crisis. Wind turbines are often erected off-shore because of favourable wind conditions, requiring lower towers than on-shore. The doubly-fed induction generator is one of the most widely used generators with wind turbines. In such a wind turbine the power converters are less robust than the generator and other mechanical parts. If any switch failure occurs in the converters, the wind turbine may be seriously damaged and have to stop. Therefore, converter health monitoring and fault diagnosis are important to improve system reliability. Moreover, to avoid shutting down the wind turbine, converter fault diagnosis may permit a change in control strategy and/or reconfigure the power converters to permit post-fault operation. This research focuses on switch fault diagnosis and post-fault operation for the converters of the doubly-fed induction generator. The effects of an open-switch fault and a short-circuit switch fault are analysed. Several existing open-switch fault diagnosis methods are examined but are found to be unsuitable for the doubly-fed induction generator. The causes of false alarms with these methods are investigated. A proposed diagnosis method, with false alarm suppression, has the fault detection capability equivalent to the best of the existing methods, but improves system reliability. After any open-switch fault is detected, reconfiguration to a four-switch topology is activated to avoid shutting down the system. Short-circuit switch faults are also investigated. Possible methods to deal with this fault are discussed and demonstrated in simulation. Operating the doubly-fed induction generator as a squirrel cage generator with aerodynamic power control of turbine blades is suggested if this fault occurs in the machine-side converter, while constant dc voltage control is suitable for a short-circuit switch fault in the grid-side converter.
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Oliveira, Ãtila GirÃo de. "Neural classifier aplied in stator winding inter-turn short circuit in three-phase induction motors driven by frequency converter." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12285.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorThis dissertation reports applications of artificial neural networks to detect stator winding interturn fault of three phase induction motor drived by frequency inverter. The artificial neural networks, like Simple and Multilayer Perceptron, served as off-line classifiers to short-circuit fault condition or healthy condition. In the training of Multilayer Perceptron, two different algorithms are used: the error back-propagation, which is a classic algorithm, and the extreme learning machine, as a relative new alternative for the classic back-propagation. The new one is more worthwhile because of its implementation easiness and higher speed of computation. The database used on the training and validation of the networks is created from an experimental setting, therefore it is composed by true data. The attributes used as failuresâ indicators are selected from certain frequencies of the spectrum, based on some theories of current signature analysis. In the second instance, the technique of principal components analysis is employed. The results obtained for the designed classifiers are shown, and some considerations are made on their use in real time embedded applications, which is the most important projection for future researches.
Este trabalho deriva da aplicaÃÃo de redes neurais artificiais para a detecÃÃo de curto-circuito entre espiras em motor de induÃÃo trifÃsico, acionado por inversor de frequÃncia. As redes neurais artificiais, do tipo Perceptron Simples e Multicamadas, sÃo usadas para detectar falhas de curto-circuito no bobinamento estatÃrico de motores de induÃÃo trifÃsicos de forma off-line. Para treinamento do Perceptron Multicamadas sÃo usados dois algoritmos distintos: o error back-propagation, que figura como o algoritmo clÃssico na literatura especializada, e o extreme learning machine, que à uma alternativa, relativamente recente, ao algoritmo clÃssico. Este algoritmo à uma opÃÃo atraente para o desenvolvimento rÃpido de classificadores. O banco de dados usado para treinamento e validaÃÃo das redes à obtido a partir de experimentaÃÃo laboratorial, portanto composto de dados reais. Os atributos utilizados para a detecÃÃo da falha sÃo componentes de frequÃncia do espectro harmÃnico da corrente estatÃrica do motor. O critÃrio de escolha destas componentes, a priori, à fundamentado em resultados de investigaÃÃes prÃvias da assinatura de corrente e, em segunda instÃncia, à aplicada a tÃcnica de anÃlise de componentes principais. SÃo apresentados os resultados obtidospelos classificadores projetados, e feitas algumas consideraÃÃes quanto à utilizaÃÃo destes em aplicaÃÃo embarcada e em tempo real, que à a principal projeÃÃo de futuros trabalhos a partir do atual.
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Hu, Xiao Ming. "Development of a System for Testing Grid-connected Doubly Fed Induction Generators with Implementation of a Three-level Neutral-Point-clamped Converter." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29443.
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Consistent international efforts have been made over the past few decades to move the world towards an environmentally sustainable society. Wind energy conversion systems (WECSs) are one of the largest contributors within this movement. Furthermore amongst existing wind turbine power generation technologies, the doubly fed induction generator (DFIG) has been distinctively popular for its lower capital costs especially in higher power applications. In order to study the integration of this type of generator into the grid, a laboratory based DFIG test rig was developed where its complete design process is presented in this dissertation. Mathematical modelling of related system components were thoroughly investigated so as to facilitate controller design based on the internal model control (IMC) methodology. In addition, a complete soft grid synchronisation procedure for the DFIG was investigated. It was found that the application of active damping within the IMC control law resulted in reduced stator current transients during synchronisation. Control voltage excitation for the DFIG rotor circuit was achieved by the implementation of two voltage source converters (VSC’s) connected in a back-to-back configuration via a common DC-link. The rotorside converter (RSC) was responsible for regulating the machine speed whereas the grid-side converter (GSC) was responsible for regulating the DC-link voltage. In addition, these converters provided decoupled and bidirectional power flow control which enabled the DFIG to operate at sub synchronous and super synchronous speeds. A three-level VSC was chosen for the GSC control, where a resource conservative modulation algorithm that eliminates DC-link neutral voltage unbalance was implemented. The DFIG system design was simulated, and the results were verified through experimental tests performed on a 1.5kW wound rotor induction machine (WRIM). A detailed description of the laboratory setup of the DFIG is presented, and various practical limitations are discussed. It was found that the performance of the developed DFIG test rig correlated well with results of the simulations. Stable operation was achieved for various system test conditions, which indicated the system’s robustness to serve as a practical platform for future DFIG related research.
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Petrovas, Andrius. "TRIFAZIŲ ASINCHRONINIŲ VARIKLIŲ DINAMINIAI MODELIAI." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2007. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20070629.143203-98148.
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Disertacijoje siekiamas tikslas: sudaryti trifazio asinchroninio variklio matematinius modelius fazinėje koordinačių sistemoje, esant įvairiems variklio apvijų jungimo būdams, sukurti modelį tiesiaeigio asinchroninio variklio dinamikos tyrimui, jo pagrindu sudaryti kompiuterinius modelius dažniu valdomiems asinchroniniams varikliams tirti.The aim of dissertation is to develop mathematical and computer models of induction motor in phase coordinate system at various ways of stator windings connection, transform this model for investigation of dynamics of linear induction motor, and carry out computer models for investigation of frequency-controlled induction motors.
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MÖRÉE, GUSTAV. "Experimental Comparison of Losses in a Grid-connected and M2C-fed 11kW Induction Motor." Thesis, KTH, Elektrisk energiomvandling, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160705.
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This thesis analyzes the power losses in induction machines and how the losses depend on the harmonic content of the applied voltages. Two cases are compared, one case where a machine is fed with a sinusoidial voltage and one case with a modular multilevel converter (M2C). The sine is representing an ideal grid while the M2C represents a case with harmonic content. The usage of converters for electrical drive systems is increasing due to advantages when the rotor speed could be variable by changing the frequency of the voltage. This is usually increasing the efficiency of the overall system, but is also adding harmonics fed to the machine and switching losses in the converter. Low switching losses in the inverter usually create higher harmonic content that instead increases the losses of the machine. The M2C is then proposed as a converter topology that can keep the harmonic content low while keeping the switching losses relatively low. This study focuses on the iron losses, the part of the total losses that is most hard to predict or measure. Today’s methods used to calculate the iron losses are often rough approximations that do not take the impact of the harmonic content of voltage into consideration, even though the iron losses are dependent on the harmonics. Experimental results in the study show that the losses of a M2C-fed case do not differ much from a sine-fed case. The difference could be explained by low increase of iron losses caused by the small harmonic content from the M2C. The increase of iron losses was linked to the harmonic content of the voltage.Detta examensarbete analyserar effektförluster i induktionsmaskiner och hur förlusterna beror på övertonsinnehållet i den matande spänningen. Två fall kommer att jämföras, ett fall där en maskin är matad från en sinus spänning och ett fall med en modulär multinivå omvandlare (M2C). Sinusen representerar ett idealt nät medan M2C representerar ett fall med övertonsinnehåll. Användning av omvandlare för elekriska drivsystem ökar på grund av fördelarna när rotorhastighet kan varieras genom att ändra frekvensen från den matande växelriktaren. Detta ökar vanligtvis verkningsgraden på det sammanlagda systemet, men detta bidrar även med övertonsinnehåll matat till maskinen och switchförluster i omvandlaren. Låga switchförluster i omvandlaren medför oftast ett högt övertonsinnehåll som istället ökar förlusterna i maskinen. M2C är därför föreslaget som en teknik som håller övertonsinnehållet lågt medan switchförlusterna är relativt låga. Denna studie fokuserar på järnförluster, den del av de totala förlusterna som är som svårast att förutse eller mäta. De metoder som finns för att beräkna järnförlusterna är vanligtvis grova skattningar som inte tar hänsyn till inverkan från spänningens övertoninnehåll, även om järnförluster beror på övertonerna i stor utsträckning. Experimentella resultat i studien visar att förlusterna i ett M2C-matat fall inte avviker i stor utsträkning jämte ett sinusmatat fall. Skillnanen kan förklaras utifrån den lilla ökningen av järnförluster från det låga övertonsinnehållet från M2C:n. Järnförlusterna ses vara kopplade till övertonsinnehållet i spänningen.
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Trapp, Jordan Gustavo. "Gerador de indução isolado com tensão e freqüência reguladas por conversor matricial esparso." Universidade Federal de Santa Maria, 2008. http://repositorio.ufsm.br/handle/1/8454.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe induction generator has characteristics making it interesting for alternative sources of energy, such as low cost, ruggedness, low maintenance, high availability and good dynamic behavior. So, it is very much applied in alternative energy systems, where low cost, low maintenance and easy availability are essential characteristics. Although this generator is very attractive, its operation presents problems related to a poor voltage regulation, load dependent variable frequency, and the need of large size self-excitation capacitors, for standalone induction generator systems. In order to minimize these problems, this study proposes a sparse matrix converter associated to an induction generator as a way to regulate the generated voltage, fix the frequency and increase the system reliability. Moreover, it allows the reduction of the self-excitation capacitors by draining out of the generator, mostly resistive current thus, reducing capacitor costs and of the whole system size. In this dissertation is presented some simulation and practical results of a sparse matrix converter connected to the induction generator prototype developed in CEEMA laboratories. These results confirm the here presented theory and validate this work.
O Gerador de Indução é atrativo para geração de energia elétrica com fontes alternativas por apresentar baixo custo, robustez, baixo índice de manutenção, grande disponibilidade e bom comportamento dinâmico. Por isso, ele é muito aplicado em sistemas alternativos de geração de energia onde o baixo custo, baixo índice de manutenção, disponibilidade e facilidade de substituição do gerador, são características bastante apreciadas. Particularmente, no caso dos geradores de indução auto-excitados por bancos de capacitores, apesar de também eles serem atrativos, sua operação isolada apresenta problemas relacionados à regulação de tensão insatisfatória e freqüência variável dependentes da carga, e pela necessidade de capacitores de auto-excitação de tamanho e custo elevados. Os custos elevados dos bancos de capacitores ainda limitam o uso isolado do gerador de indução a pequenas unidades apenas, com potência inferior à 50kW. Esta dissertação propõe o uso do Conversor Matricial Esparso como forma de regular a tensão no gerador de indução e fixar a freqüência na carga. Além disso, o uso deste conversor possibilita drenar uma corrente do gerador em fase com sua respectiva tensão, reduzindo assim o custo dos capacitores e do sistema como um todo. São apresentados resultados de simulação e resultados práticos de um protótipo do conversor matricial esparso, desenvolvido nos laboratórios do CEEMA-UFSM para conexão ao gerador de indução. Estes resultados servem de base para a comprovação e validação da teoria desenvolvida para a integração do gerador de indução auto-excitado e do conversor matricial esparso apresentada nesta dissertação.
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Šmarda, Vladislav. "Zařízení pro Indukční ohřev pro účely uměleckého kovářství." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413148.
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This Diploma thesis deals with the design of induction heating inverter. The main subject is optimalization for blacksmiths. There is described the designing procedure for power components and also designing of control part. Then prototype of 10 kW induction heater was made.
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Suppioni, Vinicius Prado. "Métodos de compensação de desequilíbrios de tensão da rede elétrica com o uso de geradores de indução duplamente alimentados." reponame:Repositório Institucional da UFABC, 2016.
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Profa. Dra. Ahda Pionkoski Grilo PavaniTese (doutorado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, 2016.
Neste trabalho foi desenvolvida uma metodologia de controle que permite ao gerador de indução duplamente alimentado, do inglês: doubly fed induction generator - DFIG, compensar os desequilíbrios de tensão do ponto de conexão do gerador com a concessionária. Para isso, foram consideradas a configuração série do DFIG, em que o conversor do lado da rede está conectado em série, e a configuração tradicional do DFIG com um restaurador dinâmico de tensão associado a ela. A metodologia de controle proposta permite compensar o desequilíbrio de tensão e minimiza as oscilações de torque produzidas por correntes desequilibradas no gerador, as quais podem reduzir a sua vida útil. Além disso, foi proposta uma solução para a operação no regime subsíncrono do DFIG na configuração série, na qual a saturação do fluxo concatenado, devido à elevação da tensão do estator, é uma limitação. A modelagem das metodologias propostas e simulações foram feitas em ambiente Matlab - Simulink, onde foram gerados os resultados necessários para sua validação.
In the present work it has been developed a control methodology allowing to the Doubly Fed Induction Generator (DFIG) to compensate the voltage unbalance at the Point of Commom Coupling (PCC). This methodology was implemented in the series configuration of the DFIG, which the Grid Side Converter is series connected to the grid, and in the traditional configuration of the DFIG with a Dynamic Voltage Restorer associated. The proposed methodology allows compensating the voltage unbalance at the PCC and reduces the electromagnetic toque oscillations produced by the unbalanced currents at the generator windings, which can compromise the machine service life. Furthermore, it has been proposed a solution to avoid increasing the stator voltage at the subsynchronous operation of the series configuration of the DFIG, which is a limitation due to the saturation of the electromagnetic flux. The proposed methodologies were modeled and simulated at the Matlab - Simulink environment, where the results required for the methodology validation was obtained.
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Vývoda, Marek. "Kompenzace účiníku a posouzení zpětných vlivů indučního ohřevu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219077.
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This Diploma thesis deals with design of for power factor correction device for mid-frequency-range induction heating and also with assessment of correction device influence in harmonically distorted environment from the distribution net point of view. Research chapters contain of main characteristics of electrical power quality and theoretical background of reactive power, which is in our case caused by driven non-linear elements. Further, the heating power supply block is explained and simulations of power consumption in Matlab - Simulink is done, within the prove of corrective tools design. After the build of corrective tool assemblies, measurements are matched with the simulation results.
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Болюх, Володимир Федорович. "Науково-технічні основи створення електромеханічних імпульсних перетворювачів індукційного типу з кріорезистивними обмотками." Thesis, НТУ "ХПІ", 2003. http://repository.kpi.kharkov.ua/handle/KhPI-Press/30142.
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Дисертація на здобуття наукового ступеня доктора технічних наук за спеціальністю 05.09.01 - електричні машини і апарати. - Національний технічний університет «Харківський політехнічний інститут», м . Харків, 2003. Дисертація присвячена проблемі створення електромеханічних імпульсних перетворю вачів індукційного типу з кріорезистивними обмотками, що охолоджуються рідким азотом. Розроблена методика розрахунку кріогенних ЕІПІТ, яка враховує комплекс взаємопов’язаних електричних, магнітних, теплових та механічних процесів з урахуванням нелінійності основ-них параметрів. Визначені основні закономірності функціонування силових та енергетичних ЕІПІТ, що забезпечують лінійний рух якоря при збудженні від ємнісного накопичувача та джерела постійної напруги. Запропоновані структурно геометричний, схемний і конструктив-ний підходи удосконалення одно- та багатосекційних ЕІПІП з обґрунтуванням їх параметрів. Отримано експериментальні дані, які підтверджують достовірність прийнятих математичних моделей і технічних рішень. Основні результати досліджень використані при виконанні 7 держбюджетних і хоздоговірних науково-дослідних робіт, у науково-виробничих фірмах та в навчальному процесі.Thesis for a Doctor's degree in Engineering Sciences by specialty 05.09.01 – Electrical Machines and Apparatus. – National Technical University “Kharkov Polytechnic Institute”, Kharkov, 2003. The dissertation deals with designing electromechanical impulse induction converters (EIIC) with liquid-nitrogen-cooled cryoresistive windings. On the basis of generalization of accumulated data in impulse electromechanics, a technique for designing cryogenic EIICs has been developed which takes into account interrelated electrical, magnetic, thermal, and mechanical complex processes with nonlinear critical parameters. The basic mechanisms of power and energy EIIC functioning which result in linear motion of the armature when the converter is excited from a capacitive accumulator or a constant-voltage source have been revealed. Structure-geometry, circuit, and design approaches for perfecting single- and multi-stage EIICs with valid parameters have been suggested. Experimental data have been obtained to validate developed mathematical models and engineering solutions. The main research results have been utilized and implemented at execution of seven state and commercial research projects, in research enterprises, and for students’ training.
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Malik, Naveed ur Rehman. "Modelling, Analysis, and Control Aspects of a Rotating Power Electronic Brushless Doubly-Fed Induction Generator." Doctoral thesis, KTH, Elektrisk energiomvandling, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174349.
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This thesis deals with the modeling, analysis and control of a novel brushlessgenerator for wind power application. The generator is named as rotatingpower electronic brushless doubly-fed induction machine/generator (RPEBDFIM/G). A great advantage of the RPE-BDFIG is that the slip power recoveryis realized in a brushless manner. This is achieved by introducing an additionalmachine termed as exciter together with the rotating power electronicconverters, which are mounted on the shaft of a DFIG. It is shown that theexciter recovers the slip power in a mechanical manner, and delivers it backto the grid. As a result, slip rings and carbon brushes can be eliminated,increasing the robustness of the system, and reducing the maintenance costsand down-time of the turbine. To begin with, the dynamic model of the RPE-BDFIG is developed andanalyzed. Using the dynamic model, the working principle of the generatoris understood and its operation explained. The analysis is carried out atspeeds, ±20% around the synchronous speed of the generator. Moreover, thedynamics of the generator due to external load-torque disturbances are investigated.Additionally, the steady-state model is also derived and analyzed forthe machine, when operating in motor mode. As a next step, the closed-loop control of the generator is considered indetail. The power and speed control of the two machines of the generator andthe dc-link voltage control is designed using internal model control (IMC)principles. It is found that it is possible to maintain the stability of thegenerator against load-torque disturbances from the turbine and the exciter,at the same time maintain a constant dc-link voltage of the rotor converter.The closed-loop control is also implemented and the operation of the generatorwith the control theory is confirmed through experiments.In the third part of the thesis, the impact of grid faults on the behaviourof the generator is investigated. The operation of the generator and its responseis studied during symmetrical and unsymmetrical faults. An approachto successful ride through of the symmetrical faults is presented, using passiveresistive network (PRN). Moreover, in order to limit the electrical and mechanicaloscillations in the generator during unsymmetrical faults, the dualvector control (DVC) is implemented. It is found that DVC to a certain extentcan be used to safeguard the converter against large oscillations in rotorcurrents. Finally, for completeness of the thesis, a preliminary physical design ofthe rotating power electronic converter has been done in a finite elementsoftware called ANSYS. The thermal footprint and the cooling capability,with estimates of the heatsink and fan sizes, are presented. Besides, another variant of a rotating electronic induction machine whichis based on the Lindmark concept and operating in a single-fed mode is also investigated. It’s steady-state model is developed and verified through experiments.QC 20151006
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Caillierez, Antoine. "Etude et mise en oeuvre du transfert de l'énergie électrique par induction : application à la route électrique pour véhicules en mouvement." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC010/document.
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La transmission d’énergie par induction est devenue un sujet extrêmement porteur compte tenu du contexte géopolitique et environnemental du moment ; ainsi que des possibilités technologiques. Les enjeux de l’alimentation électrique d’un véhicule en roulant sont importants : réduction de la taille de la batterie embarquée, du poids et du coût du véhicule, limitation des importations de cellules de batteries et réduction des importations pétrolières au profit d’investissements locaux et extension du rayon d’action des véhicules électriques voire hybrides rechargeables pouvant aller d’un simple bonus à un rayon d’action infini selon le dimensionnement de l’infrastructure.La solution développée utilise le vecteur magnétique. Elle fait donc appel à des bobines faiblement couplés qui impliquent de fortes inductances de fuite et des chutes de tensions associées hors du commun. Un nouveau type de convertisseur « continu-continu » a été imaginé afin de répondre à ces contraintes. Celui-ci se fonde sur le concept de symétrie ; l’analyse détaillée basée sur les diagrammes de Fresnel, a conduit à l’élaboration d’un fonctionnement particulier qui a été appelé la « recopie de tension ». Le prototype réalisé fonctionne avec un entrefer réaliste de 15 centimètres, une tolérance au décentrage de +/-50% sur l’axe longitudinal, une tension de sortie stable avec de faibles pertes malgré d’importantes variations de couplage. Le tout sans aucune communication entre la partie au sol et la partie mobile. Ces résultats permettent d’envisager sérieusement un fonctionnement en roulant.Celui-ci nécessite de pouvoir séquencer l’alimentation d’une multitude de bobines de petite taille enfouies sous la chaussée, au bon moment et à la bonne position. La mise en court-circuit résonnant des bobines inactive permet d’utiliser la mesure des courants pour déterminer précisément l’instant d’activation de la bobine suivante. Cette solution originale, qui s’affranchi de tout capteur de position, conserve la propriété de recopie de tension et le principe de dimensionnement développés dans la première partieInductive power transfer has become a flourishing subject, considering the current geopolitical and environmental situation and the new technological possibilities. The electric road may lead to important and valuable consequences: extended range for electric vehicles and even hybrids, from a simple bonus to an infinite range, depending on the infrastructure set up, down-sized on-board batteries, reduction of the weight and cost of the vehicle and lowered importations of both battery cells and oil for the benefit of local investments .The solution developed uses a magnetic medium for the transfer. Therefore, it involves loosely coupled coils, implying inevitably strong leakage inductances and outstanding associated voltage drops. A new type of DC-DC converter was imagined to answer those issues. It is based on the concept of symmetry; a detailed analysis conducted with phasor diagrams leads to a specific working principle, which has been named the “voltage copying”. Thus, the DC/DC converter designed works with a realistic air-gap of 15 centimeters, a longitudinal tolerance to displacement up to +/-50% and a stable output voltage with low losses despite large coupling variations. And it all works without any communication between the ground part and the mobile part. These results make a dynamic charging seriously worth investigating.It requires to sequence the power supply of a multitude of small coils buried beneath the road surface, at the right time and for the right position. Putting inactive coils in a resonant short-circuit mode enables to use current measures to precisely detect the switching time from one coil to the next. This original solution, free of any position sensor, does not prevent the specific “voltage copying” property and the design principles developed in the first part
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Engström, Staffan. "Wind Farms Influence on Stability in an area with High Concentration of Hydropower Plants." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-158447.
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The number of large-scale wind farms integrated to the power system in Sweden is increasing. Two generator concepts that are widely used are Doubly-Fed Induction Generators (DFIG) and Full Power Converters (FPC). The study is of a quantitative character and the aim of the Master thesis is to compare DFIG-models with FPC-models integrated in an area with high concentration of hydropower. Then it is possible to examine how the dynamics in the power system change depending on the selection of technology (DFIG or FPC) when connecting a wind farm. The power system is simulated during a summer night, i.e., a low load is connected. The Master thesis covers stability analysis of the power system by using rotor angle stability that are split into small-signal stability and transient stability (time-domain simulations) and finally voltage stability to see how the hydropower generators react when varying the power production in the wind farm. The Master thesis concludes that independently of wind turbine technique, integration of a wind farm has slight impact on the stability in the power system compared to a power system without a wind farm, even though the load is low. Further, an integration of a wind farms affects the reactive power production in neighbouring hydropower plants. Finally, when increasing the size of the wind farm the neighbouring hydropower station consume less reactive power which can induce problem with the voltage stability.
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LIMA, Nelio Neves. "Operação do gerador de indução em conexão assíncrona com a rede monofásica." Universidade Federal de Goiás, 2010. http://repositorio.bc.ufg.br/tede/handle/tde/999.
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Previous issue date: 2010-03-26This text reports the effort to present a proposal of a power generation system based on cage rotor Induction Electrical Machine associated to a sinusoidally-switched PWM (Pulse Width Modulation) frequency converter responsible for maintaining constant 60 Hz frequency at the generator leads. DC side at the PWM converter is nonsynchronously connected to a single-phase utility line by means of a full-bridge current-fed thyristor inverter, employing a step-down DC-DC converter in order to turn the grid injected current into a sinusoidal waveform. The proposed system allows for the operation as cogenerator in sites fed by single-phase utility net where there is availability of energetic resources. The DC capacitor voltage (Vdc) is controlled through the DC side energy balance adjusting the amplitude of the active current sent to the utility grid. The control strategy employed was the analogic proportional-integral (PI) error compensation. The system is also able to act as reactive power compensator to the AC loads as the Cdc capacitor represents a voltage source to the inverter and the three-phase diode bridge allows for bidirectional power flow between AC and DC sides. Simulation and experimental results has corroborated system viability to provide three-phase balanced regulated voltages complying with ANEEL 505/2001 Resolution and with IEEE Std 519-1992.
Este trabalho apresenta a proposta de um sistema para geração de energia elétrica baseado na Máquina de Indução Trifásica (MIT) com rotor tipo gaiola de esquilo associada a um conversor de freqüência chaveado no modo PWM (modulação por largura de pulsos na sigla em inglês) senoidal. O lado CC do conversor de frequência é conectado assincronamente à rede monofásica da concessionária através de um inversor monofásico em ponte completa a tiristores, alimentado em corrente, e de um conversor CC-CC abaixador de tensão, utilizado para modular senoidalmente a corrente injetada na rede via inversor. Este sistema permite a operação como co-gerador em localidades alimentadas por linhas monofásicas e com disponibilidade de recursos energéticos. O conversor de freqüência é responsável por manter a freqüência fundamental nos terminais do gerador de indução fixa em 60 Hz. A tensão no capacitor Ccc (Vcc) é controlada através da manutenção do balanço energético no lado CC do conversor PWM, ajustando a amplitude da corrente ativa injetada na rede monofásica em um valor adequado. A estratégia empregada para implementação do controle foi a compensação analógica tipo proporcional-integral (PI) do erro de Vcc. O sistema é ainda capaz de atuar como compensador de potência reativa para as cargas CA, já que o capacitor Ccc representa uma fonte de tensão contínua para o inversor e a ponte trifásica a diodos permite o fluxo bidiredional de energia entre os lados CA e CC do sistema. Os resultados de simulação e experimentais sustentam a viabilidade do sistema para prover tensões trifásicas equilibradas e reguladas, satisfazendo os requisitos da resolução 505/2001 da ANEEL e da norma IEEE Std 519-1992 do IEEE/ANSI.
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Žižka, Pavel. "Trakční měniče velkých výkonů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217585.
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This master thesis is based on realization of the previous university project, design of locomotive reconstruction and solving accompanying problems. In this thesis there are described all parts of a converter. The end of thesis involved theory about driver circuits of power transistors IGBT. Nowadays is still more often to think about reconstruction of the old technology rather than design a complete new construction. Investors take this decision from the financial reasons and because to the old technology designer can add only the converter. In this instant we talk about electrical locomotive, there should be kept a supply transformer and a driving unit (DC engine). The aim of this thesis is to design the converter between these two basic parts. The converter must taking the quasi-sinusoidal current which is in the phase with the input voltage, also must be able to control the engine and recuperate energy back to the network. For realization of these conditions, the converter must contain the active rectifier working in the DC-link and from which the step-down DC/DC converter is fed. Converter output is connected to the driving unit. The digital control of the power transistors is provided by processor MOTOROLA DSP56F. The control impulses, switching the power transistors, go through the driver circuits to transistors. All problems are described in the following text.
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Chadha, Ankit. "Tapped-Inductor Buck DC-DC Converter." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1578488939749599.
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Mitka, Darius. "Roboto valdymo sistema." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2004. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2004~D_20040621_172148-76217.
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The final work of master studies reviews various industrial robots constructions and parameters, from which they are characterized. Robotics systems and control of flexible production have been discussed in here. Various robots’ drives and their control advantages and disadvantages are analyzed. In the practical part original robot global movement platform is suggested and algorithm of two flexible production bays handling is created. Static characteristics of linear drive used in platform are calculated. Using software package “Matlab Simulink” model of symmetrical linear induction motor (LIM) is created and dynamic characteristics are gained. Concluding part presents inferences and suggestions.
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Сабокар, Олег Сергійович. "Удосконалення магнітно-імпульсного обладнання для технологій ремонту транспортних засобів." Thesis, Харківський національний автомобільно-дорожній університет, 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/39634.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.09.13 – техніка сильних електричних та магнітних полів. Національний технічний університет "Харківський політехнічний інститут", Харків 2019.
Дисертація присвячена вирішенню завдання поліпшення технічних показників обладнання магнітно-імпульсної обробки металів (міоми) для використання в технологіях металообробки і технологіях ремонту транспортних засобів. У роботі представлена розробка альтернативної конструкції вузла заряду ємнісних накопичувачів енергії та розробка системи індукційного нагріву. Дано числові показники нагріву при варіації часових параметрів збуджуючого струму і конструктивних параметрів інструменту індуктора. Розглянута модель системи збудження струму індуктора доповнена експериментальними дослідженнями системи в режимі резонансу напруги. Запропоновано використання модифікованої часової форми біполярного меандру сигналу збудження для зменшення кількості спектральних складових. Сконструйована система індукційного нагріву, що працює в режимі резонансу напруги, показала свою працездатність і ефективність. Було запропоновано виконувати збудження коливань струму імпульсами напруги модифікованої форми з частотою нижче на 20% від резонансної частоти, що забезпечує прийнятний ККД в режимі роботи системи без навантаження. Розробка система індукційного нагріву пройшла апробацію і випробування на підприємствах "Веда Авто Сервіс" (м. Київ) і АТ "Елеватормлинмаш" (м. Харків). Результати дисертаційної роботи використовують при підготовці бакалаврів та магістрів на кафедрі автомобільної електроніки Харківського національного автомобільно-дорожнього університету.Thesis for the degree of Candidate of Technical Sciences for specialty 05.09.13 "Equipment of strong electric and magnetic fields" – National Technical University "Kharkiv Polytechnic Institute". Kharkiv, 2019. The thesis is dedicated to the solution of the problem of the technical performance of magnetic-impulse metal processing equipment improving for use in metal-working technologies and vehicle repair technologies. The paper presents the development of an alternative design for the capacitive energy storage charge system and the development of an induction heating system. The numerical heating indicators was given with a variation of the time parameters of the exciting current and the design parameters of the inductor tool. The system model of inductor current excitation in the mode of current resonance was considered and supplemented by experimental studies of the system in voltage resonance mode. The use of a modified time form of the bipolar meander of the excitation signal to reduce the number of spectral components was proposed. The induction heating system designed that operates in the voltage resonance mode has shown its efficiency. It was proposed to perform the excitation of current oscillations by voltage pulses of the modified form with a frequency lower than 20% of the resonant frequency, which ensures acceptable efficiency in the system operation without load. The development of the induction heating system has been tested and implicated at the enterprises of "Veda Auto Service" (Kyiv) and "Elevatormlinmash" (Kharkiv). The results of the thesis are used in the preparation of bachelors and masters degree at the department of automobile electronics of the Kharkiv National Automobile and Highway University.
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Pforr, Johannes. "Single-ended resonant pre-converters for high-frequency induction heaters." Thesis, Teesside University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489035.
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Saleh, Kamel Subhi. "Sensorless Control of High Power Induction Motors Using Multilevel Converters." Thesis, University of Nottingham, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523161.
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Law, Yiu-yip Charles, and 羅耀業. "Loss analysis of a stepping inductor VRM converter." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29477918.
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Сабокар, Олег Сергійович. "Удосконалення магнітно-імпульсного обладнання для технологій ремонту транспортних засобів." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/39631.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.09.13 – техніка сильних електричних та магнітних полів. Національний технічний університет "Харківський політехнічний інститут", Харків 2019.
Дисертація присвячена вирішенню завдання поліпшення технічних показників обладнання магнітно-імпульсної обробки металів (міоми) для використання в технологіях металообробки і технологіях ремонту транспортних засобів. У роботі представлена розробка альтернативної конструкції вузла заряду ємнісних накопичувачів енергії та розробка системи індукційного нагріву. Дано числові показники нагріву при варіації часових параметрів збуджуючого струму і конструктивних параметрів інструменту індуктора. Розглянута модель системи збудження струму індуктора доповнена експериментальними дослідженнями системи в режимі резонансу напруги. Запропоновано використання модифікованої часової форми біполярного меандру сигналу збудження для зменшення кількості спектральних складових. Сконструйована система індукційного нагріву, що працює в режимі резонансу напруги, показала свою працездатність і ефективність. Було запропоновано виконувати збудження коливань струму імпульсами напруги модифікованої форми з частотою нижче на 20% від резонансної частоти, що забезпечує прийнятний ККД в режимі роботи системи без навантаження. Розробка система індукційного нагріву пройшла апробацію і випробування на підприємствах "Веда Авто Сервіс" (м. Київ) і АТ "Елеватормлинмаш" (м. Харків). Результати дисертаційної роботи використовують при підготовці бакалаврів та магістрів на кафедрі автомобільної електроніки Харківського національного автомобільно-дорожнього університету.Thesis for the degree of Candidate of Technical Sciences for specialty 05.09.13 "Equipment of strong electric and magnetic fields" – National Technical University "Kharkiv Polytechnic Institute". Kharkiv, 2019. The thesis is dedicated to the solution of the problem of the technical performance of magnetic-impulse metal processing equipment improving for use in metal-working technologies and vehicle repair technologies. The paper presents the development of an alternative design for the capacitive energy storage charge system and the development of an induction heating system. The numerical heating indicators was given with a variation of the time parameters of the exciting current and the design parameters of the inductor tool. The system model of inductor current excitation in the mode of current resonance was considered and supplemented by experimental studies of the system in voltage resonance mode. The use of a modified time form of the bipolar meander of the excitation signal to reduce the number of spectral components was proposed. The induction heating system designed that operates in the voltage resonance mode has shown its efficiency. It was proposed to perform the excitation of current oscillations by voltage pulses of the modified form with a frequency lower than 20% of the resonant frequency, which ensures acceptable efficiency in the system operation without load. The development of the induction heating system has been tested and implicated at the enterprises of "Veda Auto Service" (Kyiv) and "Elevatormlinmash" (Kharkiv). The results of the thesis are used in the preparation of bachelors and masters degree at the department of automobile electronics of the Kharkiv National Automobile and Highway University.
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Wheeler, Jeremy Nicholas. "Back-to-back converters for variable speed motor drive applications." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294550.
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Boulanger, Isabelle. "Lillgrund Wind Farm Modelling and Reactive Power Control." Thesis, KTH, Elektriska energisystem, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119256.
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The installation of wind power plant has significantly increased since several years due to the recent necessity of creating renewable and clean energy sources. Before the accomplishment of a wind power project many pre-studies are required in order to verify the possibility of integrating a wind power plant in the electrical network. The creation of models in different software and their simulation can bring the insurance of a secure operation that meets the numerous requirements imposed by the electrical system. Hence, this Master thesis work consists in the creation of a wind turbine model. This model represents the turbines installed at Lillgrund wind farm, the biggest wind power plant in Sweden. The objectives of this project are to first develop an accurate model of the wind turbines installed at Lillgrund wind farm and further to use it in different kinds of simulations. Those simulations test the wind turbine operating according to different control modes. Also, a power quality analysis is carried out studying in particular two power quality phenomena, namely, the response to voltage sags and the harmonic distortion. The model is created in the software PSCAD that enables the dynamic and static simulations of electromagnetic and electromechanical systems. The model of the wind turbine contains the electrical machine, the power electronics (converters), and the controls of the wind turbine. Especially, three different control modes, e.g., voltage control, reactive power control and power factor control, are implemented, tested and compared. The model is tested according to different cases of voltage sag and the study verifies the fault-ride through capability of the turbine. Moreover, a harmonics analysis is done. Eventually the work concludes about two power quality parameters.
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Aldahan, Leith, and Ivan Kudoori. "Utvärdering av roterande borstlösfrekvensomformare tillspårledningar." Thesis, KTH, Hälsoinformatik och logistik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-252801.
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Spårledningar används inom tunnelbanan för att visa tågets position samt bestämma tågets hastighet genom att bryta spänningsamplituden i signalen vid olika frekvenser. Frekvensen till spårledningen fås från en roterande frekvensomformare. I dagens anläggning används roterande frekvensomformare med borstar. Dessa avger i relärum mycket värme och ger miljöproblem i form av koldamm från borstarna. Det befintliga systemet är gammal och har funnits i drift över 30 år, därför håller reservdelar på att ta slut samt service till systemet svårtillgängligt. Detta examensarbete har undersökt möjligheten att uppgradera till nyare system som bygger på en lösning med roterande borstlös frekvensomformare där reservdelarna och service är tillgängliga i minst 25 år. Undersökningen jämför olika roterande borstlösa frekvensomformare från olika leverantörer för att hitta en frekvensomformare där kraven från Trafikförvaltningen uppfylls. Studien har haft fokus på problemområdet med borstade frekvensomformaren som producerar skadliga ämnen såsom koldamm och värmen i relärum. Diskussioner med tillverkningsföretag av roterande borstlös frekvensomformaren har skett under denna studies gång där möjliga alternativ för vidare utveckling av systemet i relärum analyseras. I projektet har även diskuterat möjligheten att använda det nya systemet av frekvensomformare med borstlösa motor och generator istället för den nuvarande borstade frekvensomformaren som finns i anläggningen. Resultatet har även visat att den roterande borstlösa frekvensomformaren kan omvandla frekvensen till 75 Hz. Det nya systemet uppfyller kraven från Trafikförvaltningen samt att systemet håller i minst 25 år till. Att systemet håller minst i 25 år till var ett stort krav av Trafikförvaltningen som uppfylldes under denna studie.Track lines are used in subway stations to show the train locations and determine the speed of the train by chopping the frequency. The frequency of the track lines is obtained from a rotary frequency converter. In today's stations, rotary frequency converters with brushes are commonly used. These emit a great deal of heat in some relays and produce environmental problems in the form of carbon dust from the brushes. The existing systems have been used for over 30 years and obtaining spare parts and conducting maintenance on the systems can be difficult. This degree project examines the possibility of newer systems being built on a rotating brushless frequency converter, where the spare parts and servicing would be available for at least the next 25 years. The project surveys and compares different rotating brushless frequency converters from different suppliers to find an identical frequency converter to meet the requirements of the Traffic Administration. The result of this study has had a lot of focus on the problem area with the brushed frequency converter that produces harmful substances such as carbon dust and the heat in the relay room. Discussions with manufacturing companies of rotating brushless frequency converters have been made during this study where possible options were discussed for further development of the system in relay rooms. The result has also discussed the possibilities of using the new system of frequency converters with brushless motor and generator instead of the current brushed frequency converter available in the facility. The result has also shown that the rotating brushless frequency converter can convert the frequency to 75 Hz. The new system meets RAMS requirements of the Trafikförvaltning, and the system lasts for at least 25 years. This was a major requirement of the Trafikförvaltning, which was fulfilled during this study.
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Phillipson, Christopher John. "The generation of a polyphase supply from a VSCF induction generator with single-phase excitation." Thesis, Nottingham Trent University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298842.
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Choi, Jae-Young. "Analysis of Inductor-Coupled Zero-Voltage-Transition Converters." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28537.
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As is the case for DC-DC converters, multi-phase converters require both high-quality power control and high power-density. Although a higher switching frequency not only improves the quality of the converter output but also decreases the size of the converter, it increases switching losses and electromagnetic interference (EMI) noise. Since the soft-switching topologies reduce the switching losses of the converter main switches, the topologies make converters partially independent from the switching frequency. However, the conventional soft-switching topologies have already proposed most of the possible ways to improve converter performance. In addition, the trends of the newly generated power devices reduce the advantages of soft-switching topologies. This critical situation surrounding soft-switching topologies gives research motivations: What features of soft-switching topologies facilitate their practical applications? Given this motivation, the dissertation discusses two aspects = simplifying auxiliary circuits and accounting for the effects of soft-switching operations on the converter control.
Engineers working with medium- and high-power multi-phase converters require simplified soft-switching topologies that have the same level of performance as the conventional soft-switching topologies. This demand is the impetus behind one of the research objectives = simplifying the auxiliary circuits of Zero-Voltage-Transition (ZVT) inverters. Simplifying the auxiliary circuits results in both a smaller number of and lower cost for auxiliary components, without any negative impact on performance. This dissertation proposes two major concepts for the simplification - the Single-Switch Single-Leg (S3L) ZVT cell and the Phase-Lock (PL) concept.
Throughout an effort to eliminate circulating currents of inductor-coupled (IC) ZVT converters, the S3L ZVT cell is developed. The proposed cell allows a single auxiliary switch to achieve zero-voltage conditions for both the top and bottom main switches, and it achieves the same level of performance as the conventional ZVT cell, as well. This proposal makes IC ZVT topologies more attractive to multi-phase converter applications.
Because all of the top main switches generally have identical sequences for zero-voltage turn-on commutations, one auxiliary switch might handle the commutations of all of the top main switches. This possibility introduces the PL concept, which allows the two auxiliary switches to provide a zero-voltage condition for any main switch commutation. In order to compensate for restrictions of this concept, a modified space-vector modulation (SVM) scheme also is introduced.
A soft-switching topology changes the duty ratios of the converter, which affects the controllability of the converter. Therefore, this dissertation selects resolution of this issue as one of the research objectives. This dissertation derives the generalized timing equations of ZVT operations, and the generalized equations formulize the effect of ZVT operation on both duty ratios and DC current. Moreover, the effect of SVM schemes is also investigated. An average model of the ZVT converter is developed using both the timing analysis and the investigation of SVM schemes, and small-signal analysis using the average model predicts the steady-state characteristics of the converter.Ph. D.
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Nakibuuka, Norah Elena. "A hybrid switched-capacitor/inductor converter for small conversion ratios." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85453.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013."May 2013." Cataloged from PDF version of thesis.
Includes bibliographical references (pages 67-69).
A hybrid three-switch DC-DC step-up power converter for on chip applications is proposed. It is shown that the hybrid-three switch step-up converter can offer advantages such as reduced size of magnetic components, reduced MOSFET voltage stresses, improved closed loop control and can offer high efficiency compared to a standard boost converter of the same IC package size. These improvements are made possible by adding a flying capacitor that reduces the voltage stresses on the switches and decreases the inductor size by reducing the volt-second across the inductor. The converter is implemented as an integrated circuit built in a 0.25[mu]m 5V CMOS process. Experimental verification shows the gains.
by Norah Elena Nakibuuka.
M. Eng.
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Billis, Gerald. "The design and evaluation of a microprocessor-controlled triac cycloconverter two-phase induction motor drive." Thesis, Hong Kong : University of Hong Kong, 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1285072X.
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Král, Michal. "Zkušební pracoviště synchronních generátorů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221178.
Full textAbstract:
This diploma thesis deals with a part of synchronous generator testing stand project. Thesis is focused on drive part of testing stand, the appropriate drive is chosen according to type of the tests. The attention is mainly on drive control, specifically on the configuration of frequency converter and software programming of the converter control in NI LabVIEW. Software also contains drive simulation program. Testing stands are sequentially installed and commissioned.
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Baggu, Murali Mohan. "Advanced control techniques for doubly fed induction generator-based wind turbine converters to improve low voltage ride-through during system imbalances." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Baggu_09007dcc806684bd.pdf.
Full textAbstract:
Thesis (Ph. D.)--Missouri University of Science and Technology, 2009.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 27, 2009) Includes bibliographical references (p. 126-130).
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Loup, Martin. "Modely stejnosměrných tranzistorových měničů v programu Simulink." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-412975.
Full textAbstract:
The master’s thesis is focused on the creation of models of DC/DC converters and control program for input parameters and their configuration. The first part is theoretical and she is dedicated to the description of the program Matlab. The second chapter is dedicated to DC/DC converters. Their function is described there and the necessary equations for the design are derived. All of this is complemented by the calculation of line losses in semiconductor elements and the design of voltage and current regulator. The last two parts deal with the description of the created models in Simulink and control program in a graphical environment. The created program is able to edit and recalculate parameters of the converters, calculate line losses on semiconductor components, perform a model simulation or open it.
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Jenkinas, Piotras. "Tiesiaeigės dažninės pavaros tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2004. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2004~D_20040608_172437-19296.
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The properties of linear induction motor and areas of its application are analyzed; frequency converters and their control methods are discussed in this final work. Methods to realize a pulse width modulation are analyzed, scalar and vector control principles as well as perspectives of perfection of semiconductor commutating elements and control systems are discussed. The principle of operation of control systems applied in frequency converters is analyzed On the base of analysis mathematical and Simulink model of linear induction motor in α-β reference frame is developed, mathematical and Simulink models of frequency controlled linear induction drives are carried out. Two models of linear frequency controlled induction drive: scalar and vector control are investigated, transient characteristics of inverter output voltage, currents of linear motor, developed force and linear speed are analyzed and results of different control principles are compared.
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Koon, Suet Chui. "Integrated charge-control single-inductor dual-output switching converters /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20KOON.
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King, Charles Jackson III. "Single-inductor, multiple-output buck converter with parallel source transient recovery." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53132.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Includes bibliographical references (leaves 65-66).
To address the need for multiple regulated voltage supplies in electronic devices, this thesis presents a modeling and design study of a single-inductor, multiple-output (SIMO) DC-DC buck converter with parallel source transient recovery. This converter would provide substantial cost and space savings over traditional options for producing multiple supply voltages. Operating in pseudo-continuous conduction mode (PCCM), it can supply heavy loads while not suffering from cross-regulation problems. The parallel current source circuitry at each output will greatly dampen any voltage spikes that may occur due to sudden load changes, thus improving transient performance. While the entire converter could not be nicely simulated as envisioned, the initial steps and accomplishments outlined in this thesis show definite promise. The proposed converter certainly merits further research, as the problems encountered here most likely stem from implementation and control issues rather than fundamental flaws in the idea.
by Charles Jackson King III.
M.Eng.
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Nonaka, Alan. "Boost Converter Inductor Sizing Effects on the Performance of MPPT Algorithms." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2229.
Full textAbstract:
With solar power and other renewables set to take over the market in the coming decades, maximum power point tracking will be essential to optimizing power output. One underserved topic of research is the effect of inductor current ripple on performance of Maximum Power Point Tracking (MPPT) algorithms. Many new topologies are focused on decreasing the ripple from PV source to increase efficiency and power output. However, not much has been done to show ripple degrading performance of MPPT algorithms. This study uses a boost converter topology to test the performance of constant duty cycle step Perturb and Observe (PO), Incremental Conductance IC, and Constant Voltage (CV) PID over a range of inductor current ripple factor. Inductor current ripple is controlled solely by changing inductance. This study concluded that all three algorithms were quite robust and affected very little over an inductor current ripple factor range of 20% to 40%. One novel finding was increased duty cycle oscillation when the MPPT update and sample speed was faster than the boost converter response.
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Chen, Haoning (William). "LLC Resonant Current Doubler Converter." Thesis, University of Canterbury. Electrical and Computer Engineering, 2013. http://hdl.handle.net/10092/8492.
Full textAbstract:
The telecommunications market is one of the large rapidly growing fields in today’s power supply industry due to the increasing demand for telecom distributed power supply (DPS) systems. The half-bridge LLC (Inductor-Inductor-Capacitor) resonant converter is currently the most attractive topology for the design and implementation of 24V/48V DC telecom power converters. The current doubler rectifier (CDR) converter topology was invented and described in the early 1950s which can offer the unique characteristic of halving the output voltage while doubling the output current compared to a standard rectifier. In this thesis, the current doubler converter topology with its unique characteristic is evaluated as a complementary solution to improve the LLC resonant converter performance, especially for the low output voltage and high output current telecommunication applications. A novel half-bridge LLC resonant current doubler converter (LLC-CDR) is proposed in this thesis which can offer several performance benefits compared to conventional LLC-standard rectifier design . The unique characteristics of the LLC-CDR topology can offer significant improvements by transformation of a 48V converter into a 24V converter with the same power density. This thesis introduces a new SPICE-based simulation model to analyse the operation of this novel LLC-CDR converter circuit design. This model can be used to define the critical component parameters for the LLC -CDR circuit output inductor values. It can also be used to predict the circuit overall performance under different load conditions. Both time-domain based transient simulation analysis and frequency-domain based AC analysis provided by this simulation model showed favourable results in comparison to bench measurement results on a prototype. The model
provides a valuable insight to reveal some of the unique characteristics of this LLC -CDR topology. It demonstrates a proof of concept that the conventional LLC resonant
converter can be easily redesigned for low voltage, high current applications by using the LLC-CDR topology without requiring a new design for the LLC resonant stage components and the power transformer. A new magnetic integration solution was proposed to significantly improve the overall performance in the LLC-CDR topology that had not been published before. The LLC-CDR converter hardware prototypes with two output inductors coupled and uncoupled configurations were extensively modelled, constructed and bench tested.Test results demonstrated the suitability of an integrated coupled inductors design for the novel LLC-CDR converter application. The integrated coupled inductors design can significantly improve the LLC-CDR converter frequency-domain based AC simulation analysis results. In addition, these results also illustrate the potential benefit of how the magnetic integration design in general could reduce the magnetic component size, cost, and weight compared to the uncoupled inductors design. Finally, a hardware prototype circuit was constructed based on a commercial 1800 W single phase telecom power converter to verify the operation of this novel half bridge LLC-CDR topology. The converter prototype successfully operated at both no load and full load conditions with the nominal output voltage halved from 48VDC to 24VDC, and doubled the output current to match the same output power density. It also demonstrates that the efficiency of this novel half bridge LLC –CDR is 92% compares to 90% of EATON’s commercial 24VDC LLC resonant converter, which can fulfill the research goals.