No description available.

The Permanent Magnet Synchronous Motors (PMSM) have wide application in the robotics field due to its efficiency and reliability. As a servo system, it demands high precision in different control applications. Torque ripple is a critical issue resulting in mechanical vibrations and shortening the life of PMSMs, especially at low speeds. Because the magnitude of speed harmonics is proportional to the magnitude of the torque harmonics of the same order, methods to reduce speed harmonics can be utilized for torque ripple minimization. This thesis work proposes three methods for torque ripple reduction. One method is based on harmonic speed control (HSC) and harmonic current control (HCC). Another method uses the fuzzy to adjust PI parameters based on HSC-HCC. The third method utilizes torque ripple estimation (TRE) and HCC. In the proposed methods, torque ripples are estimated using a torque ripple model (TRM). At low speeds, speed harmonics and current harmonics are obtained based on an adaptive linear neural-based filter. The errors between the optimal harmonic current reference from HSC or TRE and the harmonic current from extraction are used to generate harmonic voltage in HCC. This harmonic voltage is fed back to compensate and reduce torque ripple. Furthermore, a feedforward compensation method is proposed to minimize torque ripple across a range of speeds based on the feedback compensation results. Finally, simulations and experiments are carried out to demonstrate the validity and performance of the proposed torque ripple reduction methods.

Rund 70 % der Energieaufnahme von elektrischen Antriebssystemen wird von quasistationären Antrieben in Transportanlagen hervorgerufen. Eine gesteigerte Energieeffizienz führt neben reduzierten Energiekosten zu weiteren Nutzeffekten, wie z.B. einem verringerten Kühlaufwand, einem kleinerem Bauraum und einer höheren Lebensdauer der Komponenten. Zur Steigerung der Energieeffizienz dieser Transportanlagen werden in dieser Arbeit Methoden zur Auslegung der zugehörigen Antriebssysteme unter besonderer Berücksichtigung des Förderprozesses erarbeitet. Als repräsentative Transportanwendungen werden Pumpen- und Förderbandanlagen untersucht. Dabei wird das gesamte elektromechanische System analysiert, um das volle Energiesparpotenzial zu erfassen – beginnend mit dem Lastprofil des transportierten Förderguts bis hin zur elektrischen Energieversorgung. Hierzu werden alle Systemkomponenten modelliert, um die Verluste in verschiedenen Betriebspunkten im Volllast- und Teillastbereich abzuschätzen. Darauf aufbauend erfolgt die Erarbeitung praktikabler Projektierungshinweise und prozessspezifischer Auswahldiagramme, welche eine schnelle Vorauswahl der energieeffizientesten Antriebstopologie ermöglichen. Da die Verlustmodelle auf frei zugänglichen Datenblattangaben basieren, können die vorgestellten Methoden und Auswahlkriterien bereits in einem frühen Projektierungsstadium zur Auslegung einer energieeffizienten Transportanlage angewandt werden.

O fenômeno de stick-slip, no processo de perfuração de poços de petróleo, é propiciado pela interação entre broca e formação rochosa e pode dar origem a grandes oscilações na velocidade angular podendo provocar danos irreparáveis ao processo. Neste trabalho, analisa-se o desempenho de leis de controle aplicadas à mesa rotativa (responsável por movimentar a coluna de perfuração), visando à redução de stick-slip e de oscilações da velocidade angular da broca. As leis de controle implementadas são do tipo PI (Proporcional-Integral), com parcelas de torque aplicado à mesa rotativa, proporcional e integral à velocidade da mesa, podendo ser com peso na broca constante ou variável. Para a coluna de perfuração, foi proposto um modelo em elementos finitos com função de forma linear. O torque na broca foi modelado segundo atrito de Coulomb pela forma não regularizada, curva esta ajustada pelos dados empíricos conforme propostas da literatura. Diversos critérios de desempenho foram analisados e foi observado que a minimização do desvio médio da velocidade angular em relação à referência propicia melhores condições de operação. Análises paramétricas dos ganhos de controle proporcional e integral foram realizadas, dando origem a curvas de nível para o desvio médio de velocidade angular na broca. A partir destas curvas, foram definidas regiões de estabilidade nas quais o desvio é aceitável. Estas regiões foram observadas serem maiores para menores pesos na broca e maiores velocidades angulares de referência e vice-versa. A adição do controle do peso na broca permitiu uma redução global dos níveis de desvio médio de velocidade angular, dando origem a um aumento das regiões de estabilidade do processo de perfuração. / The stick-slip phenomenon, in the process of drilling oil wells, due to the interaction between drill and rock formation can lead to large fluctuations in drill-bit angular velocity and, thus, cause irreparable damage to the process. In this work, the performance of control laws applied to the rotary table (responsible for moving the drill string) is analyzed, in order to reduce stick-slip and drill-bit angular velocity oscillations. The control laws implemented are based on a PI (Proportional-Integral) controller, for which the torque applied to the rotating table has components proportional and integral to table angular velocity with constant or variable WOB (Weight On Bit). For the drillstring, a finite element model with a linear interpolation was proposed. The torque on the drill-bit was modeled by a non-regularized Coulomb friction model, with parameters that were adjusted using empirical data proposed in literature. Several performance criteria were analyzed and it was observed that the minimization of the mean deviation of the drill-bit angular velocity relative to the target one would provide the best operating condition. Parametric analyses of proportional and integral control gains were performed, yielding level curves for the mean deviation of drill-bit angular velocity. From these curves, stability regions were defined in which the deviation is acceptable. These regions were observed to be wider for smaller values of WOB and higher values of target angular velocity and vice-versa. The inclusion of a controlled dynamic WOB reduced the levels of mean deviation of angular velocity, leading to improved stability regions for the drilling process.

Com o passar do tempo, nota-se um aumento gradativo da demanda por veículos mais econômicos e que disponham de itens capazes de aumentar o conforto e a segurança. Citase, como exemplo, o controle de cruzeiro (Cruise Control) que, atualmente presente em diversos veículos, é responsável por controlar a velocidade do veículo de maneira autônoma, sem a necessidade de intervenção do condutor no pedal de aceleração, resultando em um aumento de conforto ao reduzir o esforço para dirigir, além de prover efetividade para manter a velocidade do veículo em torno de um valor desejado. Neste contexto, o presente trabalho apresenta o desenvolvimento de um controlador de cruzeiro para operar em um veículo modelo Volkswagen Polo Sedan 2.0L 2004, o qual não possui este recurso em seu estado de fábrica. Para a implementação deste recurso, o trabalho faz uso de uma unidade de gerenciamento eletrônico (conhecida também por Electronic Control Unit - ECU) desenvolvida em 2013, no âmbito do projeto Otto II (PEREIRA, 2013), para controle do motor presente no respectivo veículo, viabilizando, desta forma, a validação do controle de cruzeiro por meio de testes utilizando o veículo em um dinamômetro inercial. Entretanto, previamente ao projeto do controlador de cruzeiro, o presente trabalho teve como foco o aperfeiçoamento do funcionamento desta ECU, visando a sua evolução no que diz respeito ao estado da arte de unidades de gerenciamento eletrônico de motores. Para isto, em sua primeira fase, o trabalho realizou diversas melhorias nas malhas de controle já existentes no firmware de 2013, tais como controle de marcha lenta, controle da borboleta eletrônica e controle de partida. Ao mesmo tempo, novos recursos foram implementados em firmware: controle de torque, controle da mistura ar/combustível em malha fechada (sonda lambda), segurança na comunicação entre blocos da ECU, identificação de marcha, suporte para diagnóstico via OBD-II, dentre outros. Além destas atividades envolvendo desenvolvimento de firmware, o trabalho, ainda em sua primeira fase, promoveu o desenvolvimento de uma nova ferramenta de software que, além de ser capaz de monitorar diversos parâmetros da ECU em tempo real, integra diversas funções, tais como função de computador de bordo alternativo, opção para controle do motor através da simulação do pedal de aceleração, opção para alteração da rotação de marcha lenta e função para automatização do ensaio de identificação do veículo (tarefa necessária para o projeto do controlador de cruzeiro). / Over time, there is a gradual increase of the demand for economical vehicles equipped with items capable of increasing the comfort and safety. As an example, the Cruise Control, which is already available in several vehicles, is responsible to control the vehicle speed in an autonomous manner, without the driver intervention on the throttle pedal. As a result, a greater comfort is achieved by reducing the effort to drive, besides providing effectiveness to keep the vehicle speed around a desired value. In this context, this project aims the development of a Cruise Control applied to a vehicle Volkswagen Polo Sedan 2.0L 2004, in which such resource is not available. To implement this resource, the project uses an electronic engine management unit (also known as Electronic Control Unit - ECU) developed in 2013 by the Otto II project (PEREIRA, 2013). This ECU is responsible to control the engine of the respective vehicle, which allows the Cruise Control validation through a set of tests performed with the vehicle on an inertial dynamometer. However, prior to the Cruise Control design, this project focused on the ECU operation enhancement, in order to achieve the state of the art in electronic engine management units. For this goal, the project, during its first phase, performed several improvements on the control algorithms already existing in the firmware developed in 2013, such as idle speed control, electronic throttle valve control and engine starting control. At the same time, new features were fully implemented in firmware: torque control, closed loop air/fuel ratio control (lambda control), safety for the communication among ECU blocks, gear identification, support to OBD-II diagnostic, among others. In addition to the firmware development activities, the project, still in its first phase, developed a new software tool capable of monitoring several ECU parameters in real time, besides providing many functions, such as alternative board computer, an option to control the engine by simulating the throttle pedal, an option to change the idle speed and a function to automate the system identification test (task required for the Cruise Control design).

Com o passar do tempo, nota-se um aumento gradativo da demanda por veículos mais econômicos e que disponham de itens capazes de aumentar o conforto e a segurança. Citase, como exemplo, o controle de cruzeiro (Cruise Control) que, atualmente presente em diversos veículos, é responsável por controlar a velocidade do veículo de maneira autônoma, sem a necessidade de intervenção do condutor no pedal de aceleração, resultando em um aumento de conforto ao reduzir o esforço para dirigir, além de prover efetividade para manter a velocidade do veículo em torno de um valor desejado. Neste contexto, o presente trabalho apresenta o desenvolvimento de um controlador de cruzeiro para operar em um veículo modelo Volkswagen Polo Sedan 2.0L 2004, o qual não possui este recurso em seu estado de fábrica. Para a implementação deste recurso, o trabalho faz uso de uma unidade de gerenciamento eletrônico (conhecida também por Electronic Control Unit - ECU) desenvolvida em 2013, no âmbito do projeto Otto II (PEREIRA, 2013), para controle do motor presente no respectivo veículo, viabilizando, desta forma, a validação do controle de cruzeiro por meio de testes utilizando o veículo em um dinamômetro inercial. Entretanto, previamente ao projeto do controlador de cruzeiro, o presente trabalho teve como foco o aperfeiçoamento do funcionamento desta ECU, visando a sua evolução no que diz respeito ao estado da arte de unidades de gerenciamento eletrônico de motores. Para isto, em sua primeira fase, o trabalho realizou diversas melhorias nas malhas de controle já existentes no firmware de 2013, tais como controle de marcha lenta, controle da borboleta eletrônica e controle de partida. Ao mesmo tempo, novos recursos foram implementados em firmware: controle de torque, controle da mistura ar/combustível em malha fechada (sonda lambda), segurança na comunicação entre blocos da ECU, identificação de marcha, suporte para diagnóstico via OBD-II, dentre outros. Além destas atividades envolvendo desenvolvimento de firmware, o trabalho, ainda em sua primeira fase, promoveu o desenvolvimento de uma nova ferramenta de software que, além de ser capaz de monitorar diversos parâmetros da ECU em tempo real, integra diversas funções, tais como função de computador de bordo alternativo, opção para controle do motor através da simulação do pedal de aceleração, opção para alteração da rotação de marcha lenta e função para automatização do ensaio de identificação do veículo (tarefa necessária para o projeto do controlador de cruzeiro). / Over time, there is a gradual increase of the demand for economical vehicles equipped with items capable of increasing the comfort and safety. As an example, the Cruise Control, which is already available in several vehicles, is responsible to control the vehicle speed in an autonomous manner, without the driver intervention on the throttle pedal. As a result, a greater comfort is achieved by reducing the effort to drive, besides providing effectiveness to keep the vehicle speed around a desired value. In this context, this project aims the development of a Cruise Control applied to a vehicle Volkswagen Polo Sedan 2.0L 2004, in which such resource is not available. To implement this resource, the project uses an electronic engine management unit (also known as Electronic Control Unit - ECU) developed in 2013 by the Otto II project (PEREIRA, 2013). This ECU is responsible to control the engine of the respective vehicle, which allows the Cruise Control validation through a set of tests performed with the vehicle on an inertial dynamometer. However, prior to the Cruise Control design, this project focused on the ECU operation enhancement, in order to achieve the state of the art in electronic engine management units. For this goal, the project, during its first phase, performed several improvements on the control algorithms already existing in the firmware developed in 2013, such as idle speed control, electronic throttle valve control and engine starting control. At the same time, new features were fully implemented in firmware: torque control, closed loop air/fuel ratio control (lambda control), safety for the communication among ECU blocks, gear identification, support to OBD-II diagnostic, among others. In addition to the firmware development activities, the project, still in its first phase, developed a new software tool capable of monitoring several ECU parameters in real time, besides providing many functions, such as alternative board computer, an option to control the engine by simulating the throttle pedal, an option to change the idle speed and a function to automate the system identification test (task required for the Cruise Control design).

Trafikinducerade vibrationer: En studie om busskuddars påverkan på vibrationsnivåer i mark och byggnader. Erika Johansson Kling I Uppsala används busskuddar som en form av medveten ojämnhet i vägbanan för att sänka hastigheten och öka trafiksäkerheten på olycksdrabbade vägsträckor. Boende i bostäder belägna nära busskuddar har dock rapporterat att de ibland kan uppleva vibrationer kopplade till då tunga fordon passerar busskuddar som störande. Denna studie syftade till att kvantifiera vibrationsnivåer i mark och byggnader nära busskuddar samt utreda centrala faktorer som kan påverka vibrationsnivån och vibrationsutbredningen. Genom vibrationsmätningar i fält på fyra platser i Uppsala samlades data in och analyserades utifrån angivna frågeställningar. Resultatet bekräftade det som litteraturstudien belyste, att det är svårt att på ett generellt sätt beskriva vibrationsutbredningen och att den tydligt är platsspecifik. Vid samtliga undersöka platser kunde dock konstateras att vibrationsnivån i marken tenderar att vara en faktor mellan 2,5–32 högre då ett tungt fordon passerar en busskudde, jämfört med då det passerar en opåverkad referenspunkt längs med samma väg. Generellt avtog dessutom vibrationsnivån i marken med ökat avstånd från källan. Vilken vibrationsled som dominerade varierade dock både mellan platserna och för olika avstånd från källan. Vid en av de fyra mätplatserna förstärktes vibrationsnivån i byggnaden, jämfört med i marken utanför. Vid samma mätplats överskreds dessutom känseltröskeln inomhus, och en skyddsvibrationsnivå på 0,5 mm/s kan behöva tillämpas vid busskudden för att förhindra detta. Mätningarna visade att både vibrationer med låga och höga frekvenser kan uppstå i marken nära busskudden då tunga fordon passerar. Dock var det enbart vibrationer med låga frekvenser som spreds vidare i marken vid ett ökat avstånd från källan. Studien visade dessutom att det kan krävas ett skyddsavstånd mellan busskudde och byggnad på cirka 100 meter för att känseltröskeln inte ska riskera att överskridas inomhus. Trots att ett sådant avstånd är platsspecifikt, belyser det vilka krav det skulle kunna ställa på samhällsbyggnaden i ett växande Uppsala. Det faktum att busskuddar kan förhöja vibrationsnivån i marken vid passage av tunga fordon ter sig något märkligt, då busskuddarna ska vara utformade på ett sätt som tillåter tunga fordon att passera relativt obehindrat. Fler studier kring busskuddarnas utformning och/eller grundläggning är därför av stor relevans. Det är vidare relevant att exempelvis utreda hur fordonens hastighet över busskuddar påverkar vibrationsnivån i marken, då litteraturstudien belyser att det främst är då tunga fordon passerar ojämnheter med hög hastighet som betydande vibrationer kan uppstå. Busskuddar anses vara en av de mest effektiva hastighetssänkande åtgärderna, men studien visar att det kan ske på bekostnad av ökade vibrationsnivåer. En grundläggande helhetsbedömning bör därför göras av busskuddarnas lämplighet vid kommande stadsplanering. Nyckelord: markvibration, vibrationsmätning, busskudde, trafik, samhällsbyggnad. Institutionen för geovetenskaper, Uppsala Universitet, Villavägen 16, SE-752 36 Uppsala. ISSN 1401–5765. / Traffic induced vibrations: A study on the effect of speed control cushions on vibration levels in surrounding land and buildings. Erika Johansson Kling In Uppsala, speed control cushions are used as a form of conscious unevenness in the road surface to reduce speed and increase road safety on accident-affected road sections. However, housing in residences located near speed control cushions have reported that they can sometimes experience vibrations linked to when heavy vehicles pass speed control cushions as disturbing. This study aimed to quantify vibration levels in land and buildings near speed control cushions and to investigate key factors that can affect the vibration level and vibration propagation. Through vibration measurements at four places in Uppsala, data was collected and analyzed based on the stated research questions. The result confirmed what the literature study highlighted, that it is difficult to describe the propagation of vibrations in a general way and that it is clearly site-specific. However, it was found at all the measurement sites that the vibration level in the ground tends to be a factor between 2.5 and 32 higher when a heavy vehicle passes a speed control cushion, compared to when it passes an unaffected reference point along the same road. Generally, the vibration level in the ground also decreased with increased distance from the source. However, the level of vibration that dominated varied between the locations and for different distances from the source. At one measurement site, the vibration level in the building was amplified compared to in the ground outside. At the same measurement site, the sensing threshold was also exceeded indoors, and a protection vibration level of 0.5 mm/s may have to be applied nearby the speed control cushions to prevent this from happening. The measurements showed that both vibrations with low and high frequencies can occur in the ground near the speed control cushions when heavy vehicles pass. However, it was only vibrations with low frequencies that propagated further in the ground at an increased distance from the source. The study also showed that a safety distance between speed control cushions and buildings of approximately 100 meters may be required in order for the sensitivity threshold not to be exceeded indoors. Although such a distance is sitespecific, it highlights what requirements it could put on the urban planning in a growing Uppsala. The fact that speed control cushions can increase the level of vibration in the ground when heavy vehicles pass seems somewhat strange, since the speed control cushions are supposed to be designed in a way that allows heavy vehicles to pass relatively unobstructed. Additional studies on the design and/or foundation of the speed control cushions are therefore of great relevance. It is furthermore relevant to investigate, for example, how the speed of the vehicles when passing over speed control cushions affects the vibration level in the ground, since the literature study highlights that it is primarily when heavy vehicles pass an unevenness in the road surface at high speed that significant vibrations can occur. Speed control cushions are considered to be one of the most effective speed reducing measures, but the study shows that they may lead to increased vibration levels. An overall 3 evaluation should therefore be made regarding the suitability of speed control cushions in future urban planning. Keywords: ground vibration, vibration measurement, speed control cushion, traffic, urban planning. Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala. ISSN 1401–5765.

<p>This doctoral thesis presents new ideas and research results on control of marine electric power system.</p><p>The main motivation for this work is the development of a control system, power management system (PMS) capable to improve the system robustness to blackout, handle major power system faults, minimize the operational cost and keep the power system machinery components under minimal stress in all operational conditions.</p><p>Today, the electric marine power system tends to have more system functionality implemented in integrated automation systems. The present state of the art type of tools and methods for analyzing marine power systems do only to a limited extent utilize the increased knowledge available within each of the mechanical and electrical engineering disciplines.</p><p>As the propulsion system is typically consisted of the largest consumers on the vessel, important interactions exists between the PMS and vessel propulsion system. These are interacted through the dynamic positioning (DP) controller, thrust allocation algorithm, local thruster controllers, generators' local frequency and voltage controllers. The PMS interacts with the propulsion system through the following main functions: available power static load control, load rate limiting control and blackout prevention control (i.e. fast load reduction). These functions serve to prevent the blackout and to ensure that the vessel will always have enough power.</p><p>The PMS interacts with other control systems in order to prevent a blackout and to minimize operational costs. The possibilities to maximize the performance of the vessel, increase the robustness to faults and decrease a component wear-out rate are mainly addressed locally for the individual control systems. The solutions are mainly implicative (for e.g. local thruster control, or DP thrust allocation), and attention has not been given on the interaction between these systems, the power system and PMS. Some of the questions that may arise regarding the system interactions, are as follows: how the PMS functionality may affect a local thruster control, how the local thruster control may affect the power system performance, how some consumers may affect the power system performance in normal operations and thus affect other consumers, how the power system operation may affect the susceptibility to faults and blackout, how various operating and weather conditions may affect the power system performance and thus propulsion performance though the PMS power limiting control, how propulsion performance may affect the overall vessel performance, which kind of faults can be avoided if the control system is re-structured, how to minimize the operational costs and to deal with the conflicting goals. This PhD thesis aims to provide answers to such questions.</p><p>The main contributions of this PhD thesis are:</p><p>− A new observer-based fast load reduction system for the blackout prevention control has been proposed. When compared to the existing fast load reduction systems, the proposed controller gives much faster blackout detection rate, high reliability in the detection and faster and more precise load reduction (within 150 miliseconds).</p><p>− New advanced energy management control strategies for reductions in the operational costs and improved fuel economy of the vessel.</p><p>− Load limiting controllers for the reduction of thruster wear-out rate. These controllers are based on the probability of torque loss, real-time torque loss and the thruster shaft</p><p>accelerations. The controllers provide means of redistributing thrust from load fluctuating thrusters to less load fluctuating ones, and may operate independently of the thrust allocation system. Another solution is also proposed where the load limiting controller based on thrust losses is an integrated part of DP thrust allocation algorithm.</p><p>− A new concept of totally integrated thrust allocation system, local thruster control and power system. These systems are integrated through PMS functionality which is contained within each thruster PLC, thereby distributed among individual controllers, and independent of the communications and dedicated controllers.</p><p>− Observer-based inertial controller and direct torque-loss controller (soft anti-spin controller) with particular attention to the control of machine wear-out rate. These controller contribute to general shaft speed control of electrical thrusters, generators and main propulsion prime movers.</p><p>The proposed controllers, estimators and concepts are demonstrated through time-domain simulations performed in MATLAB/SIMULINK. The selected data are typical for the required applications and may differ slightly for the presented cases.</p>

This doctoral thesis presents new ideas and research results on control of marine electric power system. The main motivation for this work is the development of a control system, power management system (PMS) capable to improve the system robustness to blackout, handle major power system faults, minimize the operational cost and keep the power system machinery components under minimal stress in all operational conditions. Today, the electric marine power system tends to have more system functionality implemented in integrated automation systems. The present state of the art type of tools and methods for analyzing marine power systems do only to a limited extent utilize the increased knowledge available within each of the mechanical and electrical engineering disciplines. As the propulsion system is typically consisted of the largest consumers on the vessel, important interactions exists between the PMS and vessel propulsion system. These are interacted through the dynamic positioning (DP) controller, thrust allocation algorithm, local thruster controllers, generators' local frequency and voltage controllers. The PMS interacts with the propulsion system through the following main functions: available power static load control, load rate limiting control and blackout prevention control (i.e. fast load reduction). These functions serve to prevent the blackout and to ensure that the vessel will always have enough power. The PMS interacts with other control systems in order to prevent a blackout and to minimize operational costs. The possibilities to maximize the performance of the vessel, increase the robustness to faults and decrease a component wear-out rate are mainly addressed locally for the individual control systems. The solutions are mainly implicative (for e.g. local thruster control, or DP thrust allocation), and attention has not been given on the interaction between these systems, the power system and PMS. Some of the questions that may arise regarding the system interactions, are as follows: how the PMS functionality may affect a local thruster control, how the local thruster control may affect the power system performance, how some consumers may affect the power system performance in normal operations and thus affect other consumers, how the power system operation may affect the susceptibility to faults and blackout, how various operating and weather conditions may affect the power system performance and thus propulsion performance though the PMS power limiting control, how propulsion performance may affect the overall vessel performance, which kind of faults can be avoided if the control system is re-structured, how to minimize the operational costs and to deal with the conflicting goals. This PhD thesis aims to provide answers to such questions. The main contributions of this PhD thesis are: − A new observer-based fast load reduction system for the blackout prevention control has been proposed. When compared to the existing fast load reduction systems, the proposed controller gives much faster blackout detection rate, high reliability in the detection and faster and more precise load reduction (within 150 miliseconds). − New advanced energy management control strategies for reductions in the operational costs and improved fuel economy of the vessel. − Load limiting controllers for the reduction of thruster wear-out rate. These controllers are based on the probability of torque loss, real-time torque loss and the thruster shaft accelerations. The controllers provide means of redistributing thrust from load fluctuating thrusters to less load fluctuating ones, and may operate independently of the thrust allocation system. Another solution is also proposed where the load limiting controller based on thrust losses is an integrated part of DP thrust allocation algorithm. − A new concept of totally integrated thrust allocation system, local thruster control and power system. These systems are integrated through PMS functionality which is contained within each thruster PLC, thereby distributed among individual controllers, and independent of the communications and dedicated controllers. − Observer-based inertial controller and direct torque-loss controller (soft anti-spin controller) with particular attention to the control of machine wear-out rate. These controller contribute to general shaft speed control of electrical thrusters, generators and main propulsion prime movers. The proposed controllers, estimators and concepts are demonstrated through time-domain simulations performed in MATLAB/SIMULINK. The selected data are typical for the required applications and may differ slightly for the presented cases.

Η παρούσα διπλωματική εργασία πραγματεύεται τη μελέτη και κατασκευή ενός μετατροπέα για την οδήγηση ενός μονοφασικού επαγωγικού κινητήρα. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών. Σκοπός είναι η μελέτη και κατασκευή ενός τριφασικού αντιστροφέα τάσης για τη λειτουργία και τον έλεγχο των στροφών ενός μονοφασικού επαγωγικού κινητήρα. Αρχικά μελετάται η βασική αρχή λειτουργίας του μονοφασικού επαγωγικού κινητήρα και αναλύονται οι τεχνικές εκκίνησης που χρησιμοποιούνται για σύνδεση του κινητήρα απευθείας στο δίκτυο. Ακόμα παρουσιάζονται τα ισοδύναμα κυκλώματα λειτουργίας του μονοφασικού επαγωγικού κινητήρα, η εξίσωση της ηλεκτρομαγνητικής ροπής του και προσομοιώνεται η λειτουργία του για τη μελέτη της στατικής συμπεριφοράς του. Στη συνέχεια γίνεται μια θεωρητική ανάλυση του κυκλώματος του τριφασικού αντιστροφέα τάσης που κατασκευάστηκε, καθώς και όλων των υπόλοιπων κυκλωμάτων που είναι αναγκαία για τη λειτουργία του. Επιπροσθέτως αναλύεται η μέθοδος παλμοδότησης των διακοπτικών στοιχείων του αντιστροφέα τάσης, που είναι η "Ημιτονοειδής Διαμόρφωση του Εύρους των Παλμών" (SPWM). Στο επόμενο βήμα αναλύονται τα τεχνικά χαρακτηριστικά όλων των κυκλωμάτων που κατασκευάστηκαν, και περιγράφεται ο κώδικας του προγράμματος του μικροελεγκτή, που χρησιμοποιήθηκε για την παραγωγή των παλμών. Τέλος, παραθέτουμε παλμογραφήματα και μετρήσεις που προέκυψαν από τα πειράματα που διενεργήθηκαν μετά την ολοκλήρωση της κατασκευής. / This diploma thesis discourse the analysis and construction of a converter topology for single phase induction motor drives. The project was based in the Laboratory of Electromechanical Energy Conversion of the department of Electrical and Computer Engineering of School Engineering of University of Patras. The objective of this project is the analysis and construction of a three phase voltage inverter to control the speed of a single phase induction motor. The first stage of this work is the study of the basic principle of operation of the single phase induction motor and the analysis of the starting techniques, used for the direct connection to the power grid. The equivalent circuits of the running single phase induction motor and the equation of the electromagnetic torque are also presented in this project. Following, there is a theoretical analysis of the three phase voltage inverter circuit, as well of all the remaining circuit, necessary for its function. Moreover the method of pulse generation for the switching elements of the voltage inverter is analyzed, which is the “Sinusoidal Pulse Width Modulation”. The next step is the analysis of the technical characteristics all of the circuits developed, as well the description of the program code for the microcontroller, used to produce the pulses. Finally oscillograph figures and measurements, occurred from the experiments transacted after the finalization of the construction, are adduced.