The McTronX research group, at the Potchefstroom campus of the North–West University, has been researching Active Magnetic Bearings (AMBs). A fully suspended, flywheel energy storage system (FESS) has been developed. Due to excessive unbalance on the rotor, the motor drive could not be tested up to its rated speed. In the interim, until the rotor can be balanced and other rotor dynamic effects have been investigated, the group decided that the existing drive control should be improved and tested on a high–speed permanent magnet synchronous motor (PMSM), using normal roller element bearings. In order to test the motor control a second (identical) PMSM, mechanically coupled to the former, operates in generator mode which serves as the torque load. Two different control algorithms, namely V/f and vector control, are designed and implemented on a rapid control prototyping system, i.e. dSPACE®. The V/f control is an open–loop, position sensorless technique, whilst the vector controller makes use of a position sensor. From the design and implementation it became clear that the vector control is more robust, in the sense that it is less sensitive on parameter variations and disturbances. It can start up reliably even under full load conditions. The V/f control is an attractive alternative to the vector control, especially in AMB systems, where it may be difficult to mount the position sensor, has to operate in a hazardous environment not suited to the sensor or could degrade the reliability of the AMB system. The cost of the position sensor is not really a concern compared to the cost of an AMB system. The V/f control is more suited to fan and pump applications, which has a low dynamic requirement. The V/f control has high startup currents and is not recommended for applications requiring a high starting torque or fast acceleration during operation. The inverter, which drives the PMSM, also had to be developed. With regard to the motor control, the effects of inverter non–idealities had to be accounted, especially for the V/f control. The implemented control algorithms were tested up to 20 krpm. Discrepancies between the expected and actual results are discussed. Overall, the controllers performed as desired. Generally, the project goals have been reached satisfactorily. / Thesis (M.Ing. (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2011.

The McTronX research group, at the Potchefstroom campus of the North–West University, has been researching Active Magnetic Bearings (AMBs). A fully suspended, flywheel energy storage system (FESS) has been developed. Due to excessive unbalance on the rotor, the motor drive could not be tested up to its rated speed. In the interim, until the rotor can be balanced and other rotor dynamic effects have been investigated, the group decided that the existing drive control should be improved and tested on a high–speed permanent magnet synchronous motor (PMSM), using normal roller element bearings. In order to test the motor control a second (identical) PMSM, mechanically coupled to the former, operates in generator mode which serves as the torque load. Two different control algorithms, namely V/f and vector control, are designed and implemented on a rapid control prototyping system, i.e. dSPACE®. The V/f control is an open–loop, position sensorless technique, whilst the vector controller makes use of a position sensor. From the design and implementation it became clear that the vector control is more robust, in the sense that it is less sensitive on parameter variations and disturbances. It can start up reliably even under full load conditions. The V/f control is an attractive alternative to the vector control, especially in AMB systems, where it may be difficult to mount the position sensor, has to operate in a hazardous environment not suited to the sensor or could degrade the reliability of the AMB system. The cost of the position sensor is not really a concern compared to the cost of an AMB system. The V/f control is more suited to fan and pump applications, which has a low dynamic requirement. The V/f control has high startup currents and is not recommended for applications requiring a high starting torque or fast acceleration during operation. The inverter, which drives the PMSM, also had to be developed. With regard to the motor control, the effects of inverter non–idealities had to be accounted, especially for the V/f control. The implemented control algorithms were tested up to 20 krpm. Discrepancies between the expected and actual results are discussed. Overall, the controllers performed as desired. Generally, the project goals have been reached satisfactorily. / Thesis (M.Ing. (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2011.

Le coût, l'autonomie et la durée de vie sont les principaux aspects qui freine le public dans l'achat d'une voiture électrique. Tous ces aspects sont liés à la batterie qui ne permet de stocker qu'une quantité limitée d'énergie. Dans ces conditions, il est indispensable de maîtriser les pertes d'énergie de la chaîne de traction. La machine électrique étant le principal consommateur d'énergie, elle joue un rôle important dans l'efficacité énergétique globale. Dans ce contexte, comment réduire les pertes de la machine électrique pour la rendre plus efficace ? Pour répondre à cette question, l'objectif de ce travail est de modéliser (avec une précision suffisante) et réduire les pertes fer dans notre application machine électrique de traction afin de les maîtriser. On comblera ainsi le manque de confiance en les modèles de pertes fer que peut avoir le concepteur de machine du concepteur de machine en lui permettant de réaliser des optimisations fines jusque dans les dernières phases de développement. Dans la première partie de ce manuscrit, le lecteur découvrira alors une machine synchrone à rotor bobiné du point de vue du matériau magnétique doux. Les premières conclusions montrent qu'une modélisation fine est nécessaire pour bien prendre en compte les phénomènes générateurs de pertes. On s'intéresse également à la mesure des matériaux magnétiques doux afin de comprendre de manière générale et tangible les pertes dans le matériau. On prend également conscience de la toute première source d'incertitude des modèles, la mesure du matériau. Enfin, nous présentons les démarches couramment rencontrées dans la littérature pour la modélisation des pertes fer. Face aux limitations des modèles couramment rencontrés, le modèle LS (un modèle d'hystérésis scalaire qui décompose les pertes en une contribution statique et une contribution dynamique) est redéveloppé afin qu'il réponde encore mieux aux exigences de l'industrie automobile. Il est précis et facilement identifiable à partir de mesures faciles à réaliser. La contribution statique reprend le modèle de Preisach formulé à l'aide des fonctions d'Everett dont l'identification à partir des caractéristiques mesurées est directe. La contribution dynamique quant à elle est dorénavant identifiable à partir de caractérisations en induction sinusoïdales. La précision du modèle ainsi améliorée est ensuite validée sur 63 cas tests exigeants dont la forme de l'induction est à fort contenus harmoniques. Le modèle développé est ensuite couplé avec un modèle électromagnétique élément finis de la machine électrique et validé par l'expérience. Les mesures faites sur le matériau étant l'un des points faibles des modèles, une méthodologie permettant d'évaluer la pertinence de la plage des mesures est proposée. On dresse également un état de l'art de l'impact du process (découpage, empilement et assemblage des tôles) sur les pertes fer afin d'aider le concepteur à mettre en balance les impacts liés au process qui n'ont pu être modélisés. Enfin des méthodologies parmi lesquels, les méthodologies des plans d'expériences sont mises en place afin d'optimiser les cartographies de commandes en des temps de calcul raisonnables. On montre des gains allant jusqu'à 50% de réduction des pertes totales de la machine dans certaines zones de fonctionnement par rapport à une optimisation dont l'objectif serait de minimiser uniquement les pertes dans les conducteurs de la machine. Ces résultats montrent l'intérêt d'utiliser un modèle de pertes fer précis afin de réduire les pertes totales de la machine. / Cost, range and lifetime are the main aspects that hold back the consumer to buy electric cars. These three aspects are all related to the battery which stores a limited amount of energy. Under such condition energy consumption is a major concern in electric cars. As the major electricity consumer, electrical machines play a key role for global energy savings. In this context how the electric machine can be made more energy efficient? To answer this question this thesis aim to model (accurately enough) and reduce the iron losses in traction electrical machine for electrical car. Indeed iron loss model suffer from a lack of confidence when it comes to fine optimization during the late phase of development. This thesis answers this question and takes into account the development criteria of the car industry and the constraints of the electric car. The first part of the thesis gives an overview of the application by taking a wounded rotor synchronous machine as a case study. The reader will discover the electrical machine with a soft magnetic material perspective. First, conclusion show that fine modelling of the electric machine is necessary to achieve desired accuracy. An overview on soft magnetic material behavior and measurements is then given. The reader will then acquire a broad feeling on soft magnetic material behavior and understands the first source of inaccuracy of the models (the measurements). Then, the typical models for predicting iron losses in magnetic materials are presented in a literature review. The second part of this study focus on iron loss modelling aspect. The loss surface model (a scalar hysteresis model made of a static and dynamic contribution) is used as the base of this modelling work. The static contribution is re-developed using Everett function formulation of the Preisach model is used to allow easy identification of the model directly from measurements. The identification of the dynamic contribution is re-worked to allow identification from sine-wave measurements (triangular wave measurement previously required). The model accuracy is improved and validated on 63 test cases with high harmonic distortion wave forms. The iron loss model is then coupled to finite element model of the electric machine and the limits of the model are investigated. One of the limits coming from measurement limitation, a methodology to evaluate the relevance of the measurement range is proposed. A literature review of the main impact of the process including cutting, stacking and assembling effects on electrical steel magnetic characteristics is intended to complement the modelling work to help the decision making of the designer on aspects that cannot be modeled. Finally methodologies playing with the modelling hypothesis and involving design of experiment and response surface are presented to reduce computational time and allow the optimization of the control of the machine. The optimizations carried out show total machine loss reduction up to 50% for some working point of the machine compared to an optimization dedicated to minimize only Joule's losses. This results show the interest of using a reliable iron loss model to reduce the total loss of the machine.

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.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-03-27T15:28:12Z No. of bitstreams: 1 ramonreissiqueiradeoliveira.pdf: 4744081 bytes, checksum: dbce2e20c42a3bc456ad52a2096349ec (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-03-27T17:52:51Z (GMT) No. of bitstreams: 1 ramonreissiqueiradeoliveira.pdf: 4744081 bytes, checksum: dbce2e20c42a3bc456ad52a2096349ec (MD5) / Made available in DSpace on 2018-03-27T17:52:51Z (GMT). No. of bitstreams: 1 ramonreissiqueiradeoliveira.pdf: 4744081 bytes, checksum: dbce2e20c42a3bc456ad52a2096349ec (MD5) Previous issue date: 2017-12-18 / Uma rede com vários geradores distribuídos conectados pode melhorar a eficiência energética e reduzir o impacto negativo na rede elétrica. Um problema que surge é quando o fornecimento de energia principal é desconectado do sistema, diz-se então que ocorreu um ilhamento. Essa situação é indesejada, pois pode provocar problemas em termos de qualidade de energia, segurança, tensão e estabilidade de frequência. Esse trabalho tem por finalidade identificar o ilhamento pela variação da impedância do sistema, utilizando um método proposto que utiliza uma técnica de estimação de impedância através da injeção de um pequeno sinal na tensão de saída do gerador distribuído. Os testes realizados mostraram que quanto maior for a contribuição do inversor na potência fornecida para a carga, melhores são os valores estimados de impedância e na presença de dois inversores, os sinais injetados por cada um deles devem estar em frequências harmônicas o mais distante possível, para melhores resultados na estimação da impedância. Além disso, quando o fluxo de potência da rede para a carga é próximo de zero, o método foi capaz de identificar o ilhamento mesmo cosem atuação dos relés de tensão e frequência. O ilhamento é possível de ser identificado em aproximadamente 0,5 s em todos os casos testados, estando dessa forma dentro do tempo máximo estabelecido nas normas. / A grid with multiple distributed generators can improve energy efficiency and reduce the negative impact on itself. One problem that occurs is when the main power supply is disconnected from the system, this is called islanding. This is undesirable because it can cause problems in terms of power quality, safety, voltage and frequency stability. This work aims to identify the islanding by the system impedance variation, using a proposed method that uses an impedance estimation technique, injecting a small signal into the output voltage of the distributed generator. The tests performed showed as higher the contribution of the inverter to the power supplied to the load as better the estimated impedance values. In the presence of two inverters, the signals injected by each of them must be in harmonic frequencies, for better impedance estimation results. In addition, when the utility energy flow to the load is close to zero, the method was able to identify the same island as the voltage and frequency relays. The island can be identified in approximately 0.5 s in all cases tested, thus being within the maximum time limit set in the standards.

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.

La technologie de la réfrigération magnétique présentée dans ce manuscrit constitue une alternative prometteuse à la technologie de production de froid. Le travail effectué a porté tout d’abord sur une étude de la production de froid magnétique et un état de l’art de cette technologie émergente. Nous nous sommes fixés pour objectif de dimensionner et réaliser un réfrigérateur magnétique qui se présente sous la forme d’un actionneur intégré. Le dimensionnement a été réalisé par le biais d’un modèle à éléments finis. Il s’agit d’un dispositif présentant deux entrefers, dont un suffisamment large pour pouvoir accueillir un régénérateur magnétocalorique au sein duquel la valeur de l’induction est la plus élevée possible tout en offrant un profil d’induction de forme trapézoïdale. La réalisation du démonstrateur sur la base des étudeseffectuées par éléments finis constitue la première étape vers la réalisation d’un réfrigérateur magnétique intégré pouvant être logé dans une automobile. Pour finir, et afin d’améliorer encore les performances de notre dispositif, une optimisation de l’inducteur électromagnétique a été effectuée par le biais d’un modèle à éléments finis couplé à un algorithme d’optimisation. / The magnetic refrigeration technology is a promising alternative technology to the production of cold. The work carried out focuses on the technology of magnetic refrigeration, a state of the art of this emerging technology has also been done. A magnetocaloric regenerator is placed in the air gap of the motor. It is necessary to design a motor with an air gap wide enough and where the induction will be as high as possible in order to insert the magnetocaloric regenerator. The regenerator is a hollow cylinder whose dimensions are adapted to the air gap of the synchronous machine. It is intended to contain the magnetocaloric material. The design of the electric motor is made in order to obtain a maximal variation of induction ΔB in the air gap and a temperature difference ΔT as large as possible, improving the magnetocaloric performance of the prototype. The profile of induction should also be as close as possible to a rectangular signal. The realization of the demonstrator based on the finite element studies is the first step towards the realization of integrated magnetic refrigerator which can be housed in an automobile. Finally, and in order to improve the performance of our device, an optimization of the electromagnetic inductor was carried out with a finite element model coupled to an optimizationalgorithm.

Les travaux de cette thèse portent sur la méthodologie de conception des Machines Synchrones à Aimants Permanents (MSAP) avec pour application le véhicule électrique. Dans une première partie, nous avons abordé du contexte de l'étude et de la problématique du dimensionnement. A l'occasion, nous avons montré qu'il est nécessaire d'adopter une méthodologie de design appropriée en fonction de l'avancement de chaque projet dans le cadre du processus de conception. Nous avons alors proposé différents niveaux de modélisation afin de repérer la machine optimale face au cahier des charges pour ensuite la caractériser plus finement et l'optimiser. La seconde partie du rapport traite donc de la modélisation et de l'optimisation de la MSAP. En premier lieu, un modèle analytique permet d'évaluer les performances globales des centaines de machines très rapidement. Ce premier calcul permet de sélectionner les meilleures machines à l'application pour ensuite les optimiser. Puis, le second niveau de modélisation se base sur les réseaux de réluctances. Ce niveau plus fin permet d'une part de retrouver les performances affinées des MSAP et également de procéder à l'optimisation. Enfin, la dernière partie du rapport est consacrée à l'optimisation de la MSAP en vue d'améliorer grandement les performances et de satisfaire au mieux au cahier des charges. / The works of this thesis concern the design methodology of Permanent Magnet Synchronous Machine (PMSM) for an electric vehicle application. The first part of this report introduces the context of the study and the problem of design. Then, we have shown that it is necessary to adopt an appropriate design methodology based on the progress of each project in the design process. Thus, we proposed different levels of modeling to identify the optimal machine against the specifications, and then characterize it more finely and optimize. The second part of the report deals with the modeling and optimization of the PMSM. First, an analytical model is employed to evaluate the overall performance of hundreds of machines very quickly. The first calculation is used to select the best machine for the application and then optimize them. Then, the second level of modeling is based on reluctance networks. This model allows finer resolution of the PMSM and also permits to perform optimization. The last part of the report is devoted to the optimization of the PMSM in order to greatly improve performances and meet the specifications.

The master thesis deals with the construction and design of a high-speed synchronous machine with an outer rotor. The thesis is organised into three main chapters. The first chapter deals with machine design theory as well as mechanical limits, which are significant for high speed machines. This chapter also provides examples of applications of these electrical machines. In the second chapter, the initial design of the machine is calculated analytically. This machine design is optimised and the third chapter of this work shows the results of simulations using the finite elements method, including the evaluation of these results.