Cette thèse traite de systèmes embarqués contrôlés par un ensemble de processus périodiques non synchronisés. Chaque processus est activé quasi-périodiquement, c'est-à-dire périodiquement avec une gigue bornée. Les délais de communication sont également bornés. De tels systèmes réactifs, appelés 'quasi-périodiques', apparaissent dès que l'on branche ensemble deux processus périodiques. Dans la littérature, ils sont parfois qualifiés de systèmes distribués temps-réels synchrones. Nous nous intéressons aux techniques de conception et d'analyse de ces systèmes qui n'imposent pas de synchronisation globale. Les langages synchrones ont été introduits pour faciliter la conception des systèmes réactifs. Ils offrent un cadre privilégié pour programmer, analyser, et vérifier des systèmes quasi-périodiques. En s'appuyant sur une approche synchrone, les contributions de cette thèse s'organisent selon trois thématiques: vérification,implémentation, et simulation des systèmes quasi périodiques.Vérification: 'L'abstraction quasi-synchrone' est une abstraction discrète proposée par Paul Caspi pour vérifier des propriétés de sûreté des systèmes quasi-périodiques. Nous démontrons que cette abstraction est en général incorrecte et nous donnons des conditions nécessaires et suffisantes sur le graphe de communication et les caractéristiques temps-réel de l'architecture pour assurer sa correction. Ces résultats sont ensuite généralisés aux systèmes multi-périodiques.Implémentation: Les 'LTTAs' sont des protocoles conçus pour assurer l'exécution correcte d'une application sur un système quasi-périodique. Nous proposons d'étudier les LTTA dans un cadre synchrone unifié qui englobe l'application et les contrôleurs introduits par les protocoles. Cette approche nous permet de simplifier les protocoles existants, de proposer des versions optimisées, et de donner de nouvelles preuves de correction. Nous présentons également dans le même cadre un protocole fondé sur une synchronisation d'horloge pour comparer les performances des deux approches.Simulation: Un système quasi-périodique est un exemple de modèle faisant intervenir des caractéristiques temps-réels et des tolérances. Pour ce type de modèle non déterministe, nous proposons une 'simulation symbolique', inspirée des techniques de vérification des automates temporisés. Nous montrons comment compiler un modèle mêlant des composantes temps-réel non déterministes et des contrôleurs discrets en un programme discret qui manipule des ensembles de valeurs. Chaque trace du programme résultant capture un ensemble d'exécutions possibles du programme source. / In this thesis we study embedded controllers implemented as sets of unsynchronized periodic processes. Each process activates quasi-periodically, that is, periodically with bounded jitter, and communicates with bounded transmission delays. Such reactive systems,termed 'quasi-periodic', exist as soon as two periodic processes areconnected together. In the distributed systems literature they arealso known as synchronous real-time models. We focus on techniquesfor the design and analysis of such systems without imposing a globa lclock synchronization. Synchronous languages were introduced as domain specific languages for the design of reactive systems. They offer an ideal framework to program, analyze, and verify quasi-periodic systems. Based on a synchronous approach, this thesis makes contributions to the treatment of quasi-periodic systems along three themes: verification,implementation, and simulation.Verification: The 'quasi-synchronous abstraction' is a discrete abstraction proposed by Paul Caspi for model checking safety properties of quasi-periodic systems. We show that this abstractionis not sound in general and give necessary and sufficient conditionson both the static communication graph of the application and the real-time characteristics of the architecture to recover soundness. We then generalize these results to multirate systems.Implementation: 'Loosely time-triggered architectures' are protocols designed to ensure the correct execution of an application running on a quasi-periodic system. We propose a unified framework that encompasses both the application and the protocol controllers. This framework allows us to simplify existing protocols, propose optimized versions, and give new correctness proofs. We instantiate our framework with a protocol based on clock synchronization to compare the performance of the two approaches.Simulation: Quasi-periodic systems are but one example of timed systems involving real-time characteristics and tolerances. For such nondeterministic models, we propose a 'symbolic simulation' scheme inspired by model checking techniques for timed automata. We show how to compile a model mixing nondeterministic continuous-time and discrete-time dynamics into a discrete program manipulating sets of possible values. Each trace of the resulting program captures a set of possible executions of the source program.

This master´s thesis deals with synchronous motor model creation in MATLAB – Simulink program, with purpose of usage in AC Drives class. Models are created for motor with permanent magnets and for motor with wound rotor. The models are designed to enable simulation with both different longitudinal and transverse inductance, thus with salient rotor and non-salient rotor. The models can also be powered directly from three-phase sinusoidal source or a simple vector control can be used for their acceleration. All models are aligned so that their parameters can be set in only one m-file. Furthermore, automatic generation of phasor diagrams for steady-state motor, which serves as an interactive tool in class, is also created.

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.

Hydropower research is often perceived to be an old and exhausted field of study but with ageing equipment and the need for more intermittent operation caused by an increased share of other renewable energy sources new challenges lie ahead. The main focus of this dissertation are the electromagnetic forces resulting from nonuniform air gap flux, whether it be caused by rotor eccentricity or a faulty field winding. Results are predominantly obtained from measurements on an experimental generator and numerical simulations. With the computational capacity available today it is possible to numerically analyse physical phenomena that previously could only be studied with analytical tools. Numerical models can also be expanded to encompass more than one aspect of generator operation in coupled field-circuit models without model complexity surpassing computer capability. Three studies of unbalanced magnetic pull, UMP, in synchronous salient pole generators constitute the main part of this thesis. The first is a study of how parallel stator circuits affect the unbalanced magnetic pull caused by rotor eccentricity. Depending on the relationship between the geometry of the separate circuits and the direction of the eccentricity it was found that parallel circuits could reduce the UMP substantially. Secondly, an investigation of the effect of damper winding configuration on UMP was performed. The results showed that damper winding resistivity and the distance between the damper bars in a pole determine the effectiveness of the damper winding in reducing the UMP. Simulations of a production machine indicate that the reduction can be substantial from damper windings with low resistivity. The third study analyses the consequences of field winding interturn short circuits. Apart from a resulting rotating unbalanced magnetic pull it is found that the unaffected poles with the same polarity as the affected pole experience an increase in flux density. In a fourth article a new stand still frequency response, SSFR, test method including measurements of damper winding voltage and current is presented. It is found that the identified models are capable of predicting the stator to damper transfer function both with and without the damper winding measurements included.

Recently, permanent magnet assisted (PMa)-synchronous reluctance motors (SynRM) have been considered as a possible alternative motor drive for high performance applications. In order to have an efficient motor drive, performing of three steps in design of the overall drive is not avoidable. These steps are design optimization of the motor, identification of the motor parameter and implementation of an advanced control system to ensure optimum operation. Therefore, this dissertation first deals with the design optimization of the Permanent Magnet Assisted Synchronous Reluctance Motor (PMa-SynRM). Various key points in the rotor design of a low cost PMa-SynRM are introduced and their effects are studied. Finite element approach has been utilized to show the effects of these parameters on the developed average electromagnetic torque and the total d-q inductances. As it can be inferred from the name of the motor, there are some permanent magnets mounted in the rotor core. One of the features considered in the design of this motor is the magnetization of the permanent magnets mounted in the rotor core using the stator windings to reduce the manufacturing cost. At the next step, identification of the motor parameters is discussed. Variation of motor parameters due to temperature and airgap flux has been reported in the literatures. Use of off-line models for estimating the motor parameters is known as a computationally intensive method, especially when the models include the effect of cross saturation. Therefore in practical applications, on-line parameter estimation is favored to achieve a high performance control system. In this dissertation, a simple practical method for parameter estimation of the PMa-SynRM is introduced. Last part of the dissertation presents one advanced control strategy which utilized the introduced parameter estimator. A practical Maximum Torque Per Ampere (MTPA) control scheme along with a simple parameter estimator for PMa-SynRM is introduced. This method is capable of maintaining the MTPA condition and stays robust against the variations of motor parameters. Effectiveness of the motor design procedure and the control strategy is validated by presenting simulation and experimental results of a 1.5 kW prototype PMa-SynRM, designed and manufactured through the introduced design method.

This thesis presents a comprehensive procedure to study sub-synchronous interactions in wind integrated power systems effectively and efficiently. The proposed procedure involves a screening phase and a detailed analysis phase. The screening is performed using a frequency scan and the detailed analysis is performed using small signal stability analysis. To facilitate the small signal analysis, a detailed linearized model of a Type 3 wind power plant is presented in this thesis. The model presented includes the generator, a three-mass drive train model, rotor and grid side converter controller models, converter transformer model and the pitch controller model. To accurately capture the effects of sub-synchronous interactions, the ac network is modelled using dynamic phasors. It is shown that using the proposed procedure, the sub-synchronous interaction between a Type 3 wind power plant and a series compensated line is due to an electrical resonance between the wind power plant generator and the series capacitor. It is also shown that this interaction is highly controllable through the rotor side converter current controllers. This fact will be proven by studying the sub-synchronous interactions in a single machine power system as well as in multi machine power systems. This thesis also presents a sub-synchronous interaction mitigation method using network devices. The performance of an SVC and a STATCOM is evaluated in this thesis. A small signal stability analysis based method will be used to design a sub-synchronous damping controller. A method will be presented to estimate the damping controller parameters systematically to obtain the desired performance using small signal stability analysis results. Furthermore, it will be shown that by strongly controlling the voltage of the point of common coupling, the damping of the oscillations produced by the sub-synchronous interaction between the wind power plant and the series compensated line can be improved. Based on the findings of this research, the thesis proposes a number of recommendations to be adopted when studying the sub-synchronous interactions in wind integrated power systems. These recommendations will facilitate to do such studies effectively and pinpoint the root cause of the sub-synchronous interactions.

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.

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.

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This thesis deals with the modelling, simulation and control of Permanent Magnet Synchronous Machines (PMSM) used specially in electric and hybrid vehicles. With the availability of fast semiconductor switches and high speed processors, Vector controlled drives are gaining popularity. One disadvantage of this type of control however, is the need for high cost, high resolution sensors (encoders) for determining the rotor position. Position sensorless schemes have evolved over a decade and this thesis addresses this issue. Two schemes have been proposed for the elimination of encoders in vector controlled drives. One is a semi-sensored scheme wherein a combination of low cost hall sensors and a digital position estimator gives the position information. In the second scheme, a reduced order observer called Luenbuerger observer has been used to estimate speed and rotor angle. The problem of finding rotor angle at standstill has also been dealt with. This thesis also discusses the difference in simulating a BLDC (Brushless DC) and PMSM machine. An experimental set-up consisting of MOSFET inverter and TMS320LF2407 DSP based digital controller was developed in the laboratory to implement the control algorithms. Two PMSM machines were procured from a two-wheeler manufacturer to set up the rig. Simulations were done in MATLAB/ Simulink (Off-line) and Xilinx XC3S400 (in real-time) to verify the concepts. Simulation and experimental results are finally compared.