Thesis (MScEng)--Stellenbosch University, 2013. / Wind energy has proven to be a viable source of clean energy, and the worldwide demand is growing rapidly. Variable speed topologies, with synchronous generators and full-scale converters, are becoming more popular, and the e ective control of these systems is a current trend in wind energy research. The purpose of this study is the modelling, design, simulation and implementation of a small-scale, variable speed wind energy conversion system, incorporating the position sensorless direct torque control with space vector modulation, of a permanent magnet synchronous generator, including an RLC converter lter. Another aim is the development of a gain scheduling algorithm that facilitates the high level control of the system. Mathematical models of the combined lter-generator model, in the stationary and rotating reference frames, are presented and discussed, from which equivalent approximate transfer functions are derived for the design of the controller gains. The design of the controller gains, RLC lter components, gain scheduling concept and maximum power point tracking controller are presented. It is discovered that the RLC lter damping resistance has a signi cant e ect on the resonance frequency of the system. The system is simulated dynamically in both Simulink and the VHDL-AMS programming language. Additionally, the maximum power point tracking controller is simulated in the VHDL-AMS simulation, including a wind turbine simulator. The simulation results demonstrate good dynamic performance, as well as the variable speed operation of the system. The practical results of torque and speed controllers show satisfactory performance, and correlate well with simulated results. The detailed gain scheduling algorithm is presented and discussed. A nal test of the complete system yields satisfactory practical results, and con rms that the objectives of this thesis have been reached.

Made available in DSpace on 2016-12-12T20:27:39Z (GMT). No. of bitstreams: 1 ELISABETH CRISTINA LEMOS SPERB.pdf: 4249399 bytes, checksum: 689cbb6a5cf388bda83e27d4de4a8e1a (MD5) Previous issue date: 2011-08-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This project presents the implementation of an experimental test bed to drive the permanent magnet synchronous motor (PMSM) using a digital signal processor. The main purpose of the project is to develop a test bed with flexible features enabling the implementation and evaluation of different motor control techniques. Initially the constructive characteristics of the PMSM are studied, as the selection of the proper materials of permanent magnets and the possibilities of physical arrangement in the rotor. Then the mathematical model is developed with the currents and voltage equation in the rotating reference frame. An analysis is made, consequently, of the vector control using the method by considering the rotor flux approach with constant torque control and the space vector pulse width modulation technique. Some techniques of sensorless control based on the motor mathematical model and artificial neural network are also presented. To demonstrate the flexibility of the bed developed, some algorithms for estimating motor position and speed, earlier simulated, were implemented with the algorithm drive system. / Neste trabalho é apresentada a implementação de uma bancada experimental para o acionamento do motor síncrono de imãs permanentes (MSIP) utilizando um processador digital de sinais. O objetivo principal do trabalho é desenvolver uma bancada com características flexíveis que permita a implementação e avaliação de técnicas de controle variadas. Inicialmente, são estudadas as características construtivas do MSIP, como o material que compõe os imãs permanentes e as possibilidades de arranjo físico no rotor. Em seguida é desenvolvido o modelo matemático com as equações de corrente e tensão no referencial girante. É analisado na seqüência, o controle vetorial, utilizando o método direto pelo fluxo de rotor considerando a abordagem com controle de torque constante, e a técnica de modulação por largura de pulso por vetor espacial. São também apresentadas algumas técnicas de controle sem sensor de posição/velocidade (sensorless) baseadas no modelo matemático do motor e em redes neurais artificiais. Algumas técnicas de controle sensorless foram simuladas e analisadas. Para comprovar a flexibilidade da bancada desenvolvida, alguns algoritmos de estimação da posição e velocidade do motor, anteriormente simulados, foram implementados juntamente com o algoritmo de acionamento.

Este trabalho demonstra que o efeito de extremidade existente em atuadores eletromagnéticos lineares pode ter influência significativa nas indutâncias próprias, mútuas e síncronas, com valores dependentes da posição que podem ser utilizados para monitoração da posição axial da armadura. O estudo é aplicado a um atuador eletromagnético linear tubular de ímãs permanentes com duplo arranjo de quase-Halbach e bobina móvel, que foi concebido para fins de uso em sistemas de suspensão eletromagnética ativa e semi-ativa. A partir da revisão de literatura apresentada, classificou-se o efeito de extremidade de máquinas lineares síncronas de ímãs permanentes quanto aos tipos, causas, consequências e técnicas de mitigação (caso seja necessário). Adicionalmente, os tipos de controle sem sensores são exemplificados a fim de se identificar maneiras possíveis de adequar algum ao atuador em estudo. São apresentados casos de trabalhos na literatura que utilizam o controle sem sensores em máquinas que possuem indutâncias com comportamento semelhante. Em termos de análise, a distribuição do fluxo magnético no atuador é estudada e um modelo semianalítico é elaborado para calcular o valor das indutâncias com base nos dados de fluxo magnético obtido por simulação numérica. Logo, modelos numéricos completos e parametrizados do atuador são elaborados para simulação transiente e magnetostática e a partir destes as indutâncias são obtidas. As indutâncias também são medidas experimentalmente e na análise dos resultados as incertezas de medição são calculadas e um projeto de experimento é apresentado. Os resultados dos modelos semianalítico e numérico apresentam boa concordância com os resultados experimentais. Por fim, a adequação do atuador para futura aplicação de controle sem sensores é discutida tendo como base a variação de indutâncias devido ao efeito de extremida. / This work demonstrates that the end effect in linear electromagnetic actuators can have a significant influence on the self-, mutual and synchronous inductances, with positiondependent values that can be used to measure the axial position of the armature. The study is applied to a linear synchronous electromagnetic actuator with two arrangements of quasi- Halbach permanent magnets and moving coil, which was designed for use in active and semiactive electromagnetic suspension systems. Based on the literature review presented, the end effect of permanent magnet synchronous linear machines was classified with regard to: types, causes, consequences and mitigation techniques (if necessary). In addition, the types of sensorless control methods are exemplified in order to identify a possible method to be applied to the actuator under study. It was found in the literature that sensorless control was applied to machines that have inductances with similar behavior. In terms of analysis, the distribution of the magnetic flux in the actuator is studied and a semi-analytical model was developed to calculate the value of the inductances based on the data of magnetic flux obtained through numerical simulation. Thus, the complete parametrized numerical models of the actuator were built for transient and magnetostatic simulation, and from these the inductances were obtained. The inductances are also measured experimentally, and in the analysis of the results the measurement uncertainties are calculated and a design of experiments is presented. The results of the semi-analytical and numerical models show good agreement with the experimental results. Finally, the suitability of the actuator for future application of sensorless control is discussed based on the variation of inductances due to the end effect.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This dissertation addresses the analysis and control of permanent magnet synchronous generators (PMSG) found in wind energy conversion system. The operation modes of the wind turbine the current and voltage constraints of a PWM rectifier are defined and a methodology to determine the generator current is presented. The generator currents obtained guarantee the maximization of wind energy extraction as well as the minimization of the PMSG and rectifier losses. In addition, a space-vector modulation technique in overmodulation region is reviewed in detail and applied aiming: (i) to maximize the generator power; (ii) to utilize the entire PWM rectifier DC link voltage resource, and (iii) to obtain a smooth transition to six-step operation. Furthermore, a single current controller is designed for all operating modes being capable to avoid the controller states overload as well as the undesired effects due to the operation in the overmodulation region. The stability analysis of the closed loop system is investigated by means of linear matrix inequality conditions to estimate a region of operation with guaranteed stability. Simulation results are presented to demonstrate the performance of the proposed system. / Esta dissertação trata da análise e do controle de geradores sincronos a íımã permanente usados em sistema de conversão de energia eólica. Os modos de operação da turbina eólica sob restrição de tensão e corrente são definidos e uma metodologia para determinar as correntes do gerador ´e apresentada. As correntes obtidas do gerador garantem a maximização da potência extraída do vento bem como a minimização das perdas do conjunto gerador e retificador PWM. Além disso, a técnica de modulação vetorial na região de sobremodulação é revisada em detalhes e aplicada com objetivo de: (i) maximizar a potência do gerador, (ii) utilizar todo o recurso do barramento CC disponível pelo retificador PWM e (iii) obter uma transição suave para operação do retificador para o modo de seis-pulsos. Uma técnica de controle vetorial é apresentada e comparada. Um único controlador de corrente é projetado para todos os modos operacionais, sendo capaz de evitar tanto sobrecarga dos estados do controlador quanto os efeitos indesejáveis provenientes da operação na região de sobremodulação. A análise da estabilidade do sistema em malha fechada é investigada por meio de desigualdades matriciais lineares para determinar uma região de estabilidade garantida. Por fim, resultados de simulação são apresentados para demonstrar o bom desempenho do sistema proposto.

Made available in DSpace on 2016-12-12T17:38:33Z (GMT). No. of bitstreams: 1 Resumo - Roberto Andrich.pdf: 255410 bytes, checksum: 674d7034fd046a38194121da5d0b5f27 (MD5) Previous issue date: 2013-08-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work is presented the development of an experimental setup and a simulation plataform for the evaluation of performance in permanent magnet synchronous motors when drived with di_erent control strategies. The proposal of the experimental setup is to allow the driving and analysis of these types of motors with the main control strategies used in their applications in a easy and didactic way. The control strategies implemented are the well known Six-step technic for BLDC type motor, that is, motors having trapezoidal back-emf voltages, the classical Field Oriented Control for BLAC type motors, that is, motors having sinusoidal back-emf voltages and a modified field oriented control specially developed for non-sinusoidal back-emf voltage motors. The proposal of the simulation plataform is to estimate the results obtained in the experimental bench. This is done by implementing the same control strategies in the simulation bench and also by modelling the main losses in the driving inverter and motor. / Nesse trabalho é apresentado o desenvolvimento de uma Plataforma Experimental e de uma Plataforma de Simulação para a avaliação de desempenho em motores síncronos com ímãs permanentes quando acionados com diferentes estratégias de controle. A proposta da plataforma experimental é permitir o acionamento e a análise desses motores com as principais estratégias de controle utilizadas em suas aplicações de forma prática e didática. As estratégias implementadas são o controle Six-step para motores do tipo BLDC, ou seja, com tensões induzidas trapezoidais, o controle vetorial para motores do tipo BLAC, ou seja, com tensões induzidas senoidais e uma proposta de modificação no controle vetorial para o acionamento de motores com tensões induzidas não senoidais. A plataforma de simulação tem por objetivo estimar a priori os resultados obtidos na plataforma experimental através da implementação das mesmas estratégias de controle e do modelamento das principais perdas existentes no inversor e no motor

Este trabalho demonstra que o efeito de extremidade existente em atuadores eletromagnéticos lineares pode ter influência significativa nas indutâncias próprias, mútuas e síncronas, com valores dependentes da posição que podem ser utilizados para monitoração da posição axial da armadura. O estudo é aplicado a um atuador eletromagnético linear tubular de ímãs permanentes com duplo arranjo de quase-Halbach e bobina móvel, que foi concebido para fins de uso em sistemas de suspensão eletromagnética ativa e semi-ativa. A partir da revisão de literatura apresentada, classificou-se o efeito de extremidade de máquinas lineares síncronas de ímãs permanentes quanto aos tipos, causas, consequências e técnicas de mitigação (caso seja necessário). Adicionalmente, os tipos de controle sem sensores são exemplificados a fim de se identificar maneiras possíveis de adequar algum ao atuador em estudo. São apresentados casos de trabalhos na literatura que utilizam o controle sem sensores em máquinas que possuem indutâncias com comportamento semelhante. Em termos de análise, a distribuição do fluxo magnético no atuador é estudada e um modelo semianalítico é elaborado para calcular o valor das indutâncias com base nos dados de fluxo magnético obtido por simulação numérica. Logo, modelos numéricos completos e parametrizados do atuador são elaborados para simulação transiente e magnetostática e a partir destes as indutâncias são obtidas. As indutâncias também são medidas experimentalmente e na análise dos resultados as incertezas de medição são calculadas e um projeto de experimento é apresentado. Os resultados dos modelos semianalítico e numérico apresentam boa concordância com os resultados experimentais. Por fim, a adequação do atuador para futura aplicação de controle sem sensores é discutida tendo como base a variação de indutâncias devido ao efeito de extremida. / This work demonstrates that the end effect in linear electromagnetic actuators can have a significant influence on the self-, mutual and synchronous inductances, with positiondependent values that can be used to measure the axial position of the armature. The study is applied to a linear synchronous electromagnetic actuator with two arrangements of quasi- Halbach permanent magnets and moving coil, which was designed for use in active and semiactive electromagnetic suspension systems. Based on the literature review presented, the end effect of permanent magnet synchronous linear machines was classified with regard to: types, causes, consequences and mitigation techniques (if necessary). In addition, the types of sensorless control methods are exemplified in order to identify a possible method to be applied to the actuator under study. It was found in the literature that sensorless control was applied to machines that have inductances with similar behavior. In terms of analysis, the distribution of the magnetic flux in the actuator is studied and a semi-analytical model was developed to calculate the value of the inductances based on the data of magnetic flux obtained through numerical simulation. Thus, the complete parametrized numerical models of the actuator were built for transient and magnetostatic simulation, and from these the inductances were obtained. The inductances are also measured experimentally, and in the analysis of the results the measurement uncertainties are calculated and a design of experiments is presented. The results of the semi-analytical and numerical models show good agreement with the experimental results. Finally, the suitability of the actuator for future application of sensorless control is discussed based on the variation of inductances due to the end effect.

DC power systems have a constant DC-link voltage, as well as the advantages such as high stability, high efficiency, small size and light weight; therefore, they are widely used in stand-alone power systems, e.g. the power systems in aircrafts and automobiles, isolated wind power generation systems, etc. Permanent-Magnet Synchronous Generators (PMSGs) possess the advantages including high power density, high efficiency, and high control precision, and have obtained great attention and have been widely used in military, inductry, and daily life. Pulse Width Modulation (PWM) rectifier has been one of the main power conversion topologies thanks to its full controllability. The key point in the dissertation is to study the DC power system consisting of a PMSG to be the main power input device and a PWM rectifier to be the main power conversion topology. The objective of control is to output a constant DC-link voltage in a wide PMSG speed range. Since the PM-excited flux linkage is constant, when the PMSG is working at a high speed, field-weakening is needed to stabilize the stator voltage, further to stabilize the DC-link voltage. Hybrid excitation may be used to realize the field-weakening, but it has complex structure; no auxiliary devices are needed in the field regulation with the armature current, and can be easily realized with the PWM recifier and field-regulation control strategies. In this dissertation, the typical applications of the DC power systems are first introduced, with a comprehensive analysis and elaboration on the relevant research throughout the world. The research work is focused on the DC power system and its stabilization control, which is composed of a PMSG and a PWM rectifier. The involved research content in this dissertation includes the following aspects: 1. DC power system design with a wide-speed-range PMSGAs for the common DC power systems, PMSG with high power density, high efficiency is selected to the system power input device, usually with a variable-speed prime mover. The PWM rectifier with fully controlled switches is chosen to be the power conversion topology, which converts the AC power generated by PMSG into DC power, and supplies the DC load after the DC filter. The matching between the system requirements and the generator parameters are determined. Through finite-element analysis (FEA), a PMSG with strong field-weakening ability and suitable for wide-speed-range operation has been designed and manufactured, and the system test bench has been built based on dSPACE. 2. Study, analysis, optimization and experimental verification of the traditional control strategiesAccording to the PMSG designed in part 1, the DC-link model has been built, as well as the control model of the traditional control strategies, e.g. field-oriented control (FOC), direct torque control (DTC), and the effectiveness of the DC-link voltage stabilization control has been verified in a wide speed range. The theory of active damping has been proposed and analyzed, and has been utilized in the DC-link voltage control. When the load on the DC-link changes, the dynamic response of the DC-link voltage has been greatly accelerated, and it recovers quickly to its reference value. In the meantime, the performance influence of the prime mover speed on the actual system test bench should be considered. Finally, the performance of FOC and DTC has been compared and analyzed. 3. Analysis and experimental verification of the direct voltage control (DVC), and the comparative study of all the studied control strategiesThe derivation process of DVC has been theoretically analyzed: the inner current loops in FOC have been eliminated to obtain the direct voltage field-oriented control (DVFOC); the reference value of d-axis voltage in DVFOC has been replaced by the product of the stator voltage calculated by the speed and the load condition, and the sine value of load angle generated by the DC-link voltage PI controller, in order to form the DVC-1. Further, the DC-link voltage PI controller directly outputs the reference value of load angle and it becomes DVC-2. Finally, the comparative study has been carried out among all the studied control strategies. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Le travail de recherche présenté dans ce mémoire concerne le développement de capteurs logiciels de position pour la commande de la machine synchrone à aimants permanents. La commande vectorielle de la MSAP nécessite une connaissance précise de la position rotorique. Traditionnellement, cette position est obtenue à partir de l’utilisation d’un capteur mécanique.Depuis des années, l’attention de la communauté scientifique s’est portée sur la limitation du nombre de capteurs vu que leur présence, non seulement augmente le coût et la complexité matérielle totale, mais aussi réduit sa fiabilité avec une sensibilité additionnelle aux perturbations extérieures. Dans une première partie, nous présentons plusieurs types de capteurs logiciels deposition pour la MSAP. En fonction du régime de fonctionnement de la machine, nous proposons le capteur, selon nous, le mieux adapté pour une application automobile. Ce capteur est basé sur le couplage intelligent entre un observateur et un capteur logiciel basé sur la technique d’injection de signaux. Dans une deuxième partie, nous proposons une méthode simple et rapidepermettant l’estimation de la résistance et des inductances statoriques à l’arrêt. La méthode proposée, basée sur la technique d’injection de signaux de haute fréquence, exploite la mise en oeuvre des filtres à variable d’état afin d’obtenir un modèle linéaire par rapport aux paramètres. La combinaison de l’identification à l’arrêt et du capteur logiciel permet une bonne estimationde la position de la MSAP sur une large plage de vitesse y compris les basses vitesses et à l’arrêt. Nous abordons également certains aspects de commande de robustesse vis-à-vis de l’ensemble des paramètres incertains de la machine, mais ce de manière plus prospective. / This thesis focuses on the development of soft sensors for position control of the permanent magnet synchronous machine. Vector control of PMSM requires accurate knowledge of the rotor position. Traditionally, this position can be obtained from a mechanical sensor. Many years ago, the attention of the scientific community has focused on reducing the number of sensorsbecause their presence not only increases the cost and the total hardware complexity, but also reduces its reliability with an additional sensitivity to external disturbances. As a first step, we present several known types of soft sensors for PMSM. We present the complete design of a soft sensor for speed measurement of permanent magnet synchronous motor. The rotor speedand position can be estimated in a wide speed range even at low speed and standstill. We introduce two soft sensors operating in two different ranges of speed. Secondly, a simple method based on high frequency signal injection and exploiting the implementation of state variable filters to obtain a linear model with respect to the parameters is presented. Thus, a simplifiedprocedure of identification based on a least squares algorithm can be used. In an automotive application, the PMSM parameters can change due to temperature variation and aging of the material. Therefore, the coupling of the hybrid soft sensor and the simplified pocedure of identification provides a good estimate of the PMSM position over a wide speed range including standstill. We also consider a new approach to the robust control of the PMSM, but just as a newtrack for further investigations.

Cette thèse aborde la conception optimale des chaînes de traction par l'exemple d'une chaîne de traction pour métro. Les données d'entrée de la conception d'une chaîne de traction sont la performance attendue et l'encombrement des équipements nécessaires. Pour aider le concepteur, l'outil informatique donne aujourd'hui la possibilité de construire une grande variété de modèles. D'autre part, les algorithmes d'optimisation permettent de trouver les configurations optimales. Ces possibilités ont été exploitées au cours de ce travail. Les modèles développés permettent d'estimer un large nombre de critères. A travers l'exemple de ces modèles, la méthode de conception suivie est détaillée dans le rapport. D'un point de vue technique, la chaîne de traction proposée est détaillée dans le dernier chapitre / This thesis deals with the optimal design of electric drivetrains. A drivetrain for metro is taken as an example. The input data for the design are the expected performance and the size of the required equipments.To assist the designer, the computing tool now gives the opportunity to build different sort of models. In addition, optimization algorithms allow finding optimal configurations. This work is an attempt to exploit these possibilities. The design models are used to value a large number of criteria. Through the example of these models, the design method followed is detailed in the document. From a technical point of view, the proposed drivetrain is detailed in the last chapter

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