Дисертації з теми "Rotor current estimation and control"

As the world moves towards a cleaner and greener future, electrical machines for various industrial purposes and transport applications have gained a lot of attention. Permanent magnet synchronous machines (PMSMs) are usually the solution for electric vehicle (EV) applications thanks to their high efficiency, compactness and high-power density. On the downside, although the price of rare-earth materials has recovered close to historical levels, concerns still remain and the questions on the environmental sustainability of these materials have also been raised, which has encouraged the researchers to consider rare-earth-free machines.The switched reluctance machine (SRM) is one of the competitive alternatives, thanks to the simple and robust construction, high reliability and inherent fault tolerance capability. However, it has a bad reputation when it comes to torque ripple and acoustic noise. And the highly nonlinear characteristic brings much difficulty to routine design purposes and machine optimisation.Therefore, some of the above mentioned problems are addressed - a torque-ripple-reduction, reliable and low-cost system of SRMs is presented in this thesis. Firstly from the modelling point of view, a combined magnetic equivalent circuit (MEC) and finite element (FE) model of SRMs is developed for fast characterization the nonlinear behavior. Secondly from the control point of view, various torque-ripple reduction techniques are implemented and compared. Moreover, a minimal current sensing strategy with enhanced fault-detection capability is proposed and validated experimentally. It requires two current sensors, to replace the phase current sensors, with no additional devices for fault detection, to achieve a more compact and low-cost drive. Finally from the reliability point of view, an interturn short-circuit fault detection method and a rotor position estimation approach are investigated and validated experimentally, which leads to a more reliable system.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished

Le développement de commandes en boucle fermée pour des entraînements électriques nécessite l'installation de capteurs pour avoir l'information de la rétroaction. Cependant, un éventuel défaut survenant sur l'un des capteurs installés (de courant, de vitesse/position,…) implique un disfonctionnement de la commande conduisant dans la plupart du temps à la mise hors service du système. Ces conséquences sont contraires aux exigences des industriels qui demandent des degrés de fiabilité du système de plus en plus élevés. Des statistiques montrent que le défaut capteur est fréquent. Il est donc impératif de trouver des solutions pour assurer la continuité de service des systèmes électriques dans le cas de présence de ce type de défaut. Tout d'abord, l'étude présentée dans ce manuscrit présente les technologies des différents capteurs installés et ce pour comprendre les raisons et le type de pannes qui pourraient survenir. Ensuite, le système sur lequel la validation des algorithmes développés est décrit. Il s'agit d'un entraînement électrique basé sur une machine à Double Alimentation (MADA) fonctionnant en mode moteur et connectée au réseau via deux convertisseurs. La commande associée est une Commande Directe de Couple (CDC). Elle est validée en mode sain aussi bien par simulation qu'expérimentalement. Après, les études réalisées prennent en considération les défauts capteurs de courants alternatifs et de vitesse/position. Les algorithmes développés, permettant une continuité de service, utilisent une redondance analytique et sont basés sur l'estimation et aussi sur la Détection et l'Isolation d'un éventuel Défaut (DID). Ils sont caractérisés par leur simplicité. Aussi, ils ne sont pas gourmands en termes de consommation en ressources matérielles et leur temps d'exécution est très court. Enfin, la validation expérimentale de ces algorithmes montre bien leur efficacité en cas de défaut, vu que le système s'avère insensible au défaut et continue à fonctionner sans interruption. La commande obtenue est alors tolérante aux défauts capteurs
The development of closed loop controls for electrical drives requires the sensor installations in order to get feed back information. Nevertheless, any occurred sensor fault (current sensor,speed/position sensor,…) shows an operation system deterioration which leads in most cases to its shut down. This consequence is in contrast to industrial expectations especially concerning the system high accuracy that they are asking for. Statistic studies point out the sensor faults as frequent. So, it is necessary to find out solutions ensuring the system service continuity in case of any sensor fault. Firstly, the study presented in this work shows the used sensor technologies in order to understand both of the reason and the kind of occurred faults. Secondly, the studied system is presented which is an electrical drive based on a Doubly Fed Induction Machine (DFIM) operating in motor mode and connected to the grid by two inverters. The control developed is a Direct Torque Control (DTC). The control validation, in healthy operating mode, is realised throw simulation and experimentally. After, a study considering alternative current sensor and speed/position sensor faults are achieved. The developed algorithms are based on signal estimation, on a Fault Detection Isolation (FDI) and reconfiguration algorithms. In fact, they are simple to carry out, they don't need much hardware resources for implementation and their execution time is short. Finally, the experimental validation of the developed algorithms shows their efficiency. The system continues working even in presence of a sensor fault. Thus, the obtained control becomes a fault tolerant control thanks to these algorithms

In this work, research to develop algorithms for a package exchange maneuver between two quad-rotor aircraft is presented. First, the development of tools used for this research is discussed. Second, a controller is designed that synchronizes the flight paths and motion of two quad-rotor robots. The controller is used to guide a designated follower quad-rotor to follow a leader aircraft’s position and orientation. The follower aircraft is equipped with a simple mechanical manipulator to compensate for limitations in the aircrafts maneuverability. finally, a sensor architecture study for relative navigation of Unmanned Aerial Vehicles (UAV) is presented. The architecture study presents typical navigation solutions, considers each solution’s appropriateness for close-proximity missions, and compares performance.

The possibility to save energy in synchronous machines operation by dismissing d-axis damping bars and surrogating them with active excitation current control in sectored field winding is proved. In particular a way to recover the energy of rotor oscillations during power regulation is shown by means of a studycase generator whereas a self-starting machine is analytically and numerically designed in view of its next construction and test. Principal design requirements and limits for both applications are presented and discussed.

En esta Tesis ha sido analizado el control de la màquina sincrónica de rotor bobinado actuando en isla. Para esta configuración, la velocidad mecànica determina la frecuencia, y la tensión de rotor se utiliza para fijar la amplitud de la tensión de estator. Debido a que la constante de tiempo eléctrica es mucho más ràpida comparada con la constante de tiempo mecánica, la velocidad mecánica fue considerada constante y externamente regulada y la investigación se enfocó en la regulación de la amplitud de la tensión de estator.

Cuatro diferentes controladores basados en técnicas de modos deslizantes fueron diseñados en el marco de referencia dq. Las leyes de control obtenidas regulan la amplitud de la tensión de estator independientemte del valor de la carga. Adicionalmente, sólo las medidas de tensión y posición del rotor (para calcular la transformada dq) son necesarias. La estabilidad de los puntos de equilibrio obtenidos fueron probados al menos utilizando anàlisis de pequeña señal.

Se realizó la validación por simulación y experimental de cada controlador en diferentes escenarios. Los resultados obtenidos validan los diseños y muestran las principales ventajas y desventajas de el sistema en lazo cerrado.

El capítulo 2 cubre los problemas de modelado de la màquina sincrónica de rotor bobinado. Partiendo de las ecuaciones trifásicas generales, y utilizando la transformada de Park, se encontraron el modelo en dq del generador sincrónico de rotor bobinado (WRSG) en isla, alimentando tanto carga resistiva como inductiva. Los puntos de equilibrio del sistema obtenido fueron analizados y calculados, luego se definió el objetivo de control. Finalmente, se obtuvieron modelos lineales aproximados y sus respectivas funciones de transferencia.

Los controladores PI son los más usados en la industria porque ofrecen buen desempeño y son sencillos de implementar. En el capítulo 3, se obtuvieron las reglas de sintonización para el controlador PI, y se analizaron estos resultados con el objetivo de proponer nuevos controladores que mejoraran el desempeño de la clásica aproximación PI.

El esquema de control en modos deslizantes para la WRSG conectada a una carga resistiva fue diseñado en el capítulo 4. Éste, también incluye un completo análisis de estabilidad del sistema en lazo cerrado.

El capítulo 5 presenta dos diseños basados en modos deslizantes para regular la amplitud de la tensión de estator para el WRSG actuando en isla. Ambos diseños usan la componente d de la tensión de estator en la función de conmutación. El primer caso es un control anidado, donde un lazo externo PI es añadido para proveer la referencia de la componente d de la tensión. En la segunda aproximación un término integral es añadido a la superficie de conmutación.

El caso de alimentar una carga inductiva es estudiado en el capítulo 6. El controlador requiere una extensión dinámica debido a que la amplitud de la tensión de estator es una salida de grado relativo cero. Como resultado, un controlador robusto, que no depende de los parámetros de la máquina ni de los valores de carga es obtenido.

En el capítulo 7 los resultados de simulación y experimentales para los controladores diseñados para el WRSG actuando en isla son presentados. En primer lugar, una descripción completa del banco es presentada. Esta incluye detalles de la etapa de adquisición de datos y de la DSP utilizada. En segundo lugar, se hace la descripción del procedimiento de simulación. Luego, las simulaciones y experimentos, que contienen diferentes escenarios, con cambios de referencia y variaciones de carga para cada controlador son presentados.
The control of the stand-alone the wound rotor synchronous generator has been analyzed in this dissertation. For this islanded configuration, the mechanical speed determines the frequency, and the rotor voltage is used to set the stator voltage amplitude. Due to the electrical time constant is so fast compared with the mechanical time constants, the mechanical speed was considered constant and externally regulated and the research was focused on the stator voltage amplitude regulation.

Four different controllers based on sliding mode control techniques were designed in the dq reference frame. The obtained control laws regulate the stator voltage amplitude irrespectively of the load value. Furthermore, only voltage and rotor position measures (to compute the dq transformation), are required. The stability of the obtained equilibrium points was proved at least using small-signal analysis.

Simulation and experimental validation of each controller containing several scenarios were carried out. The obtained results validate the designs and show the main advantages and disadvantages of each closed loop system.

Chapter 2 covers the modeling issues of the wound rotor synchronous machine. From the general three-phase dynamical equations, and using the Park transformation, the dq-model of the stand-alone wound rotor synchronous generator feeding both a resistive and an inductive load are obtained. Equilibrium points of the obtained systems are analyzed and, after defining the control objective, the desired equilibrium points are computed.
Finally, linear approximated models are obtained and their transfer functions are also presented.

PI controllers are the most used in the industry because they offers good performance and are easily implementables. In Chapter 3 we obtain the tuning rule for the PI controller, and we analyze these results in order to propose new controllers which improve the classic PI approach.

The sliding mode control scheme for the WRSG connected to a resistive load is designed in Chapter 4. It also includes a complete stability analysis of the closed loop system.

Chapter 5 presents two sliding mode designs to regulate the stator voltage amplitude for a stand-alone wound rotor synchronous generator. Both use the stator voltage d-component error in the switching function. The first case is a nested controller, where an outer PI loop is added to provide the proper d-voltage component reference. In the second approach an integral term is added to the switching function.

The case of feeding an inductive load is studied in Chapter 6. The controller introduces a dynamic extension because the stator voltage amplitude is a zero relative degree output. As result, a robust controller, which neither depends on the machine parameters nor on the load values, is obtained.

In Chapter 7 the simulation and the experimental results of the designed controllers for the stand-alone wound rotor synchronous generator are presented. Firstly, a complete description of the bench is provided. It also includes details of the data acquisition stage and the used DSP card. Secondly, the description of the simulation procedure is commented. Then, the simulation and experiments which contains several scenarios, with reference change and load variations evaluated for each controller are presented.

Current consumption measurements are useful in a wide variety of applications, including power monitoring and fault detection within a lithium battery management system (BMS). This measurement is typically taken using either a shunt resistor or a Hall-effect current transducer. Although both methods have achieved accurate current measurements, shunt resistors have inherent power loss and often require isolation circuitry, and Hall-effect sensors are generally expensive. This work explores a novel alternative to sensing battery current by measuring terminal voltages and cell temperatures and using an unknown input observer (UIO) to estimate the battery current. An accurate model of a LiFePO4 cell is created and is then used to characterize a model of the proposed current estimation technique. Finally, the current estimation technique is implemented in hardware and tested in an online BMS environment. Results show that the current estimation technique is sufficiently accurate for a variety of applications including fault detection and power profiling.

Induction motors (IM) find widespread use in modern industry and for this reason they have been subject to a significant amount of research interest in recent times. One particular aspect of this research is the fault detection and diagnosis (FDD) of induction motors for use in a condition based maintenance (CBM) strategy; by effectively tracking the condition of the motor, maintenance action need only be carried out when necessary. This type of maintenance strategy minimises maintenance costs and unplanned downtime. The benefits of an effective FDD for IM is clear and there have been numerous studies in this area but few which consider the problem in a practical sense with the aim of developing a single system that can be used to monitor motor condition under a range of different conditions, with different motor specifications and loads. This thesis aims to address some of these problems by developing a general FDD system for induction motor. The solution of this problem involved the development and testing of a new approach; the adaptive mixed-residual approach (AMRA). The main aim of the AMRA system is to avoid the vast majority of unplanned failures of the machine and therefore as opposed to tackling a single induction motor fault, the system is developed to detect all four of the most statistically prevalent induction motor fault types; rotor fault, stator fault, air-gap fault and bearing fault. The mixed-residual fault detection algorithm is used to detect these fault types which includes a combination of spectral and model-based techniques coupled with particle swarm optimisation (PSO) for automatic identification of motor parameters. The AMRA residuals are analysed by a fuzzy-logic classifier and the system requires only current and voltage inputs to operate. Validation results indicate that the system performs well under a range of load torques and different coupling methods proving it to have significant potential for use in industrial applications.
The full-text was made available at the end of the embargo period on 29th Sept 2017.

Induction motors (IM) find widespread use in modern industry and for this reason they have been subject to a significant amount of research interest in recent times. One particular aspect of this research is the fault detection and diagnosis (FDD) of induction motors for use in a condition based maintenance (CBM) strategy; by effectively tracking the condition of the motor, maintenance action need only be carried out when necessary. This type of maintenance strategy minimises maintenance costs and unplanned downtime. The benefits of an effective FDD for IM is clear and there have been numerous studies in this area but few which consider the problem in a practical sense with the aim of developing a single system that can be used to monitor motor condition under a range of different conditions, with different motor specifications and loads. This thesis aims to address some of these problems by developing a general FDD system for induction motor. The solution of this problem involved the development and testing of a new approach; the adaptive mixed-residual approach (AMRA). The main aim of the AMRA system is to avoid the vast majority of unplanned failures of the machine and therefore as opposed to tackling a single induction motor fault, the system is developed to detect all four of the most statistically prevalent induction motor fault types; rotor fault, stator fault, air-gap fault and bearing fault. The mixed-residual fault detection algorithm is used to detect these fault types which includes a combination of spectral and model-based techniques coupled with particle swarm optimisation (PSO) for automatic identification of motor parameters. The AMRA residuals are analysed by a fuzzy-logic classifier and the system requires only current and voltage inputs to operate. Validation results indicate that the system performs well under a range of load torques and different coupling methods proving it to have significant potential for use in industrial applications.

The Queensland University of Technology (QUT) allows the presentation of a thesis for the Degree of Doctor of Philosophy in the format of published or submitted papers, where such papers have been published, accepted or submitted during the period of candidature. This thesis is composed of seven published/submitted papers, of which one has been published, three accepted for publication and the other three are under review. This project is financially supported by an Australian Research Council (ARC) Discovery Grant with the aim of proposing strategies for the performance control of Distributed Generation (DG) system with digital estimation of power system signal parameters. Distributed Generation (DG) has been recently introduced as a new concept for the generation of power and the enhancement of conventionally produced electricity. Global warming issue calls for renewable energy resources in electricity production. Distributed generation based on solar energy (photovoltaic and solar thermal), wind, biomass, mini-hydro along with use of fuel cell and micro turbine will gain substantial momentum in the near future. Technically, DG can be a viable solution for the issue of the integration of renewable or non-conventional energy resources. Basically, DG sources can be connected to local power system through power electronic devices, i.e. inverters or ac-ac converters. The interconnection of DG systems to power system as a compensator or a power source with high quality performance is the main aim of this study. Source and load unbalance, load non-linearity, interharmonic distortion, supply voltage distortion, distortion at the point of common coupling in weak source cases, source current power factor, and synchronism of generated currents or voltages are the issues of concern. The interconnection of DG sources shall be carried out by using power electronics switching devices that inject high frequency components rather than the desired current. Also, noise and harmonic distortions can impact the performance of the control strategies. To be able to mitigate the negative effect of high frequency and harmonic as well as noise distortion to achieve satisfactory performance of DG systems, new methods of signal parameter estimation have been proposed in this thesis. These methods are based on processing the digital samples of power system signals. Thus, proposing advanced techniques for the digital estimation of signal parameters and methods for the generation of DG reference currents using the estimates provided is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1. One of the main parameters of a power system signal is its frequency. Phasor Measurement (PM) technique is one of the renowned and advanced techniques used for the estimation of power system frequency. Chapter 2 focuses on an in-depth analysis conducted on the PM technique to reveal its strengths and drawbacks. The analysis will be followed by a new technique proposed to enhance the speed of the PM technique while the input signal is free of even-order harmonics. The other techniques proposed in this thesis as the novel ones will be compared with the PM technique comprehensively studied in Chapter 2. An algorithm based on the concept of Kalman filtering is proposed in Chapter 3. The algorithm is intended to estimate signal parameters like amplitude, frequency and phase angle in the online mode. The Kalman filter is modified to operate on the output signal of a Finite Impulse Response (FIR) filter designed by a plain summation. The frequency estimation unit is independent from the Kalman filter and uses the samples refined by the FIR filter. The frequency estimated is given to the Kalman filter to be used in building the transition matrices. The initial settings for the modified Kalman filter are obtained through a trial and error exercise. Another algorithm again based on the concept of Kalman filtering is proposed in Chapter 4 for the estimation of signal parameters. The Kalman filter is also modified to operate on the output signal of the same FIR filter explained above. Nevertheless, the frequency estimation unit, unlike the one proposed in Chapter 3, is not segregated and it interacts with the Kalman filter. The frequency estimated is given to the Kalman filter and other parameters such as the amplitudes and phase angles estimated by the Kalman filter is taken to the frequency estimation unit. Chapter 5 proposes another algorithm based on the concept of Kalman filtering. This time, the state parameters are obtained through matrix arrangements where the noise level is reduced on the sample vector. The purified state vector is used to obtain a new measurement vector for a basic Kalman filter applied. The Kalman filter used has similar structure to a basic Kalman filter except the initial settings are computed through an extensive math-work with regards to the matrix arrangement utilized. Chapter 6 proposes another algorithm based on the concept of Kalman filtering similar to that of Chapter 3. However, this time the initial settings required for the better performance of the modified Kalman filter are calculated instead of being guessed by trial and error exercises. The simulations results for the parameters of signal estimated are enhanced due to the correct settings applied. Moreover, an enhanced Least Error Square (LES) technique is proposed to take on the estimation when a critical transient is detected in the input signal. In fact, some large, sudden changes in the parameters of the signal at these critical transients are not very well tracked by Kalman filtering. However, the proposed LES technique is found to be much faster in tracking these changes. Therefore, an appropriate combination of the LES and modified Kalman filtering is proposed in Chapter 6. Also, this time the ability of the proposed algorithm is verified on the real data obtained from a prototype test object. Chapter 7 proposes the other algorithm based on the concept of Kalman filtering similar to those of Chapter 3 and 6. However, this time an optimal digital filter is designed instead of the simple summation FIR filter. New initial settings for the modified Kalman filter are calculated based on the coefficients of the digital filter applied. Also, the ability of the proposed algorithm is verified on the real data obtained from a prototype test object. Chapter 8 uses the estimation algorithm proposed in Chapter 7 for the interconnection scheme of a DG to power network. Robust estimates of the signal amplitudes and phase angles obtained by the estimation approach are used in the reference generation of the compensation scheme. Several simulation tests provided in this chapter show that the proposed scheme can very well handle the source and load unbalance, load non-linearity, interharmonic distortion, supply voltage distortion, and synchronism of generated currents or voltages. The purposed compensation scheme also prevents distortion in voltage at the point of common coupling in weak source cases, balances the source currents, and makes the supply side power factor a desired value.

Ion current sensing, where information about the combustion process in an SI-engine is gained by applying a voltage over the spark gap, is currently used to detect and avoid knock and misfire. Several researchers have pointed out that information on peak pressure location and air/fuel ratio can be gained from the ion current and have suggested several ways to estimate these parameters.

Here a simplified Bayesian approach was taken to construct a lowpass-like filter or estimator that makes use of prior information to improve estimates in crucial areas. The algorithm is computationally light and could, if successful, improve estimates enough for production use.

The filter was implemented in several variants and evaluated in a number of simulated cases. It was found that the proposed filter requires a number of trade-offs between variance, bias, tracking speed and accuracy that are difficult to balance. For satisfactory estimates and trade-off balance the prior information must be more accurate than was available.

It was also found that similar a task, constructing a general Bayesian estimator, has already been tackled in the area of particle filtering and that there are promising and unexplored possibilities there. However, particle filters require computational power that will not be available to production engines for some years.

Vid jonströmsmätning utvinns information om förbränningsprocessen i en bensinmotor genom att en spänning läggs över gnistgapet och den resulterande strömmen mäts. Jonströmsmätning används idag för knack- och feltändningsdetektion. Flera forskare har påpekat att det finns än mer information i jonströmmen, bl.a. om bränsleblandningen och cylindertrycket och har även föreslagit metoder för att utvinna och använda den informationen för skattning av dessa parametrar.

Här presenteras en förenklad Bayesisk metod i form av en lågpassfilter-liknande skattare som använder förkunskap till att förbättra estimat på relevanta områden. Algoritmen är beräkningsmässigt lätt och kan, om den är framgångsrik, leverera skattningar av förbränningsparametrar som är tillräckligt bra för att användas för sluten styrning av en bensinmotor.

Skattaren, eller filtret, implementerades i flera varianter och utvärderades i ett antal simulerade fall. Resultaten visade på att flera svåra avvägningar måste göras mellan förbättring i varians, avvikelse och följning eftersom förbättring i den ena ledde till försämring i de andra. För att göra dessa avvägningar och få goda skattningar krävs bättre förhandskunskap och mätdata än vad som var tillgängligt.

Bayesisk skattning är ett stort befintligt område inom statistik och signalbehandling och den mest generella skattaren är partikelfiltret som har många intressanta tillämpningar och möjligheter. De har hittills inte använts inom skattning av förbränningsparametrar och har således go potential för framtida utveckling. De är dock beräkningsmässigt tunga och kräver beräkningsresurser utöver vad som är tillgängliga i ett motorstyrsystem idag.

Cette thèse s’inscrit dans le cadre de la chaire Renault/Centrale Nantes sur l’amélioration des performances des véhicules électriques (EV/HEV). Elle est dédiée à la problématique de l’estimation de la position/vitesse des moteurs synchrones à aimants permanents (MSAP) sans capteur mécanique, en utilisant les techniques d’injection de signaux haute fréquence (HF) sur toute la plage de vitesse des MSAP. Dans ce cadre, plusieurs contributions ont été proposées dans les parties de démodulation/traitement du signal et d’algorithmes de poursuite des techniques d’injection HF, afin d’améliorer l’estimation de la position/vitesse des MSAP par rapport aux méthodes existantes. Dans la partie démodulation/traitement du signal des techniques d’injection HF, les contributions ont consisté à proposer des solutions originales permettant de réduire les effets de filtrage dans la chaine d’estimation et de rendre cette dernière indépendante des paramètres (électriques) de la machine. Dans la partie poursuite, les contributions portent essentiellement sur l’exploitation de la fonction signe de l’erreur de position (à la place de l’erreur de position) comme information de mesure, pour estimer la position, la vitesse et l’accélération des MSAP sans capteurs mécaniques avec des observateurs par modes glissants d’ordre 1 (classiques, étapes par étapes et adaptatifs). Les contributions proposées dans les deux parties ont pour avantages d’une part, de robustifier la chaine d’estimation en la rendant indépendante des paramètres électriques et mécaniques. Et d’autre part, d’améliorer la précision et les performances de la chaine d’estimation, et par conséquent du contrôle des MSAP sans capteurs mécaniques, dans les phases transitoires et en régimes permanents avec une méthode de réglage aisée. Les méthodes d’estimation développées ont été testées en simulation et en expérimentation sur un banc d’essai de machines électriques. Les résultats obtenus ont permis de mettre en évidence les performances de ces méthodes en terme de suivi de trajectoire et de robustesse sur toute la plage de fonctionnement des MSAP sans capteurs mécaniques
This thesis is part of the Renault / Centrale Nantes Chair on improving the performance of electric vehicles (EV / HEV). It is dedicated to the problem of estimating the position / speed of self-sensing permanent magnet synchronous motors (PMSM) without mechanical sensors, using high frequency (HF) signal injection techniques over the full speed range of PMSM. In this context, several contributions have been proposed in the demodulation / signal processing and tracking algorithms parts of HF injection techniques, in order to improve the estimation of the position / speed of the MSAP compared to the existing methods. In the demodulation / signal processing part of the HF injection techniques, the contributions consisted of proposing original solutions making it possible to reduce the filtering effects in the estimation chain and to make the latter independent of the electrical machine parameters. In the tracking part, the contributions mainly concern the use of the function sign of the position error (instead of the position error) as measurement information, to estimate the position, the speed and the acceleration of self-sensing PMSM with firstorder sliding mode observers (conventional, step-by-step and adaptive). The contributions proposed in both parts have the advantages of robustifying the estimation chain by making it independent of electrical and mechanical parameters on the one hand. On the other hand, they allow improving the accuracy and performance of the estimation chain, and therefore the control of self-sensing PMSM, in transient and steady-state phases with an easy tuning method. The estimation methods developed were tested in simulation and experimentation on a test bench of electrical machines. The results obtained made it possible to highlight the performances of these methods in terms of trajectory tracking and robustness over the entire operating range of PMSM self-sensing control

This thesis is focused on the design of vector control of interior permanent magnet synchronous motors. The first part of this work deals with vector control transformations and mathematical modelling of synchronous motors. Furthermore, algorithms of sensorless control are discussed, especially HF injection sensorless methods. One of these methods was used for torque and speed control. Problem of phase delay caused by filters and it’s compensation is also discused. One of the HF injection sensorless method was implemented on both motors. The results of simulations in MATLAB/Simulink and tests of real motors on dSpace are included.

The thesis is focused on the issue of sensorless vector control of a synchronous motor with permanent magnets in the low-speed range. In the first part, there is a brief description of the synchronous motor and the necessary transformations for the application of vector control. This is followed by the overview of sensorless methods for position estimation by injecting a high-frequency harmonic signal. The practical part is devoted to the implementation of a control algorithm to develop kit STM32NUCLEO-L476RG, which is preceded by the identification of all engine parameters. As part of the implementation, a structure including current, speed and position control was designed. The functionality and robustness of the settings have been successfully tested due to the different inertia and load.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais
This work investigates the operation of three phase induction motors in field weakening and high speed regions. Maximum torque per ampère is imposed by using an indirect vector control strategy. Mathematical models that accounts for magnetic saturation is used for simulations and adjustment of controllers used in control algorithm. The driving structure is characterized by the use of VSI static converter with sinusoidal PWM switching strategy and a vector control technique based on orthogonal components. Investigations resulted in the development of a digital simulation using discrete models that turned out generic and reliable, and an experimental system using a low cost fixed point DSP platform. Simulated and experimental results are included and shown the robustness and efficiency of the proposed control system under different operating conditions.
O presente trabalho tem como objetivo estudar a operação de motores de indução trifásicos em regime de enfraquecimento de campo e altas velocidades, com maximização do conjugado por ampère, através de um sistema de acionamento vetorial. Para tanto, foi utilizado uma modelagem matemática completa, por fase, que emprega o conceito de função harmônica magnética e considera as componentes, fundamental e de terceiro harmônico do fluxo de entreferro. A estrutura de acionamento caracteriza-se pela utilização de um inversor de tensão PWM senoidal e da técnica de controle vetorial, esta baseada em componentes ortogonais. A evolução do trabalho resultou no desenvolvimento de uma plataforma de simulação computacional baseada em modelos discretos que é bastante genérica e confiável, e um sistema experimental utilizando um processador digital de sinais de baixo custo com aritmética de ponto fixo. Os resultados de simulação e experimentais que avaliam a eficiência do sistema de controle proposto sob diversas condições de operação e efeitos de dessintonia são apresentados e apontam para robustez do método.
Doutor em Ciências

Cette thèse de doctorat regroupe ses principales contributions dans le domaine des observateurs de systèmes dynamiques, motivés à l'origine par des applications en systèmes MEMS ou NEMS (systèmes micro ou nano électromécaniques), avec un cas plus particulier lié au courant tunnel. Il est également arrivé d’envisager des expériences avec un système de lévitation magnétique.Les contributions de cette thèse sont de deux types, en fonction de ses deux parties principales:1. Partie méthodologique: concevoir différentes stratégies de contrôle pour obtenir des observateurs en utilisant le paradigme basé sur le contrôle. En particulier, nous nous sommes concentrés sur la non-optimale approches (comme Proportionnelle et Proportionnelle-Intégrale), optimale (LinéaireRégulateur Quadratique et Linéaire Quadratique Intégrateur) et méthodes sous-optimales (Contrôleur Hinf). De plus, nous nous concentrons sur les deux principaux moyens de formuler un problème de contrôle (poursuite). C'est-à-dire Le problème de régulation du retour d’erreur et Le problème de régulation en utilisant l'information complète d’état.2. Partie expérimentale: application des méthodes obtenues pour améliorer l’imagerie topographique à l’aide d’un microscope basé sur l’effet tunnel et à l’amélioration de l’estimation de perturbation sur les entres pour un processus de lévitation magnétiquePlus précisément, chaque partie prendra la forme de deux chapitres:1. Chapitre II, consacré à une introduction formelle et à une discussion contributive sur l’approche "observateur basée sur le contrôle" que cette thèse étudie, et le chapitre III, qui porte sur l’utilisation de cette approche pour la conception d’un nouveau concept d’observateur robuste, en particulier dans un cadre Hinf2. Chapitre IV, relatif à l’application STM, et Chapitre V, présentant l’affaire MAGLEV.Un dernier chapitre VI résume les principales conclusions de ce travail ainsi que certaines perspectives
This PhD thesis gathers its main contributions in the field of observers for dynamical systems, originally motivated by applications in MEMS or NEMS (Micro or Nano Electromechanical Systems), with a more particular case related to tunneling current. It also happened to consider experiments with a magnetic levitation system.Contributions of this PhD thesis are of two types, according to its two main parts:1. Methodological part: designing different control strategies to obtain observers using the control-based paradigm. In particular, we focused on non-optimal approaches (like Proportional and Proportional-Integral), optimal ones (Linear Quadratic Regulator and Linear Quadratic Integrator) and sub-optimal methods (Hinf controller). Moreover, we focus on the main two ways to formulate a control (tracking) problem, namely Error feedback regulation problem and Full information regulation problem.2. Experimental part: Applying the obtained methods for improving the topographic imaging using a Scanning-Tunneling Microscope as well as to improve the disturbance estimation for a magnetic levitation process.More precisely, each part will take the form of two chapters:1. Chapter II, dedicated to a formal introduction and contributive discussion about the ’control based observer’ approach this PhD investigates, and Chapter III, focusing on the use of such an approach for the purpose of new robust observer design in particular within an Hinf framework.2. Chapter IV, related to STM application, and chapter V, presenting the MAGLEV case.A final chapter VI summarizes the main conclusions of this work as well as some perspectives

博士
國立臺灣科技大學
電機工程系
90
This dissertation presents passivity-based adaptive control and sliding mode control schemes for the position control of an induction motor. First, the mathematical model of the induction motor in the synchronously rotating reference frame is derived from the three-phase circuit via the coordinate transformation. There is no need to design a rotor flux observer when the electrical parameters of the induction motor are known. The dynamics of the induction motor and the position controllers are analyzed to be passive by the passivity theorem. Furthermore, one can also design a rotor resistance observer and a sliding mode controller to estimate the rotor resistance and control the position of the induction motor. First, the input-output linearization theory is employed to decouple the rotor position and the flux amplitude in the rotor reference frame. Then, a flux observer is adopted to estimate the rotor flux. The passive properties of the rotor resistance observer with the flux observer and the sliding mode position controller are analyzed by the passivity theorem. The stability analysis of the overall position control system is carried out by using the passivity theorem instead of Lyapunov-type arguments. Finally, the C language is used to implement the proposed control algorithm on a PC-based controller, and applied to a three-phase induction motor for the position control purpose. Experimental results are provided to show good position response and fast convergent speed of the estimated parameters for the composite adaptive controller. The proposed sliding mode position controller with an adaptive law is valid for eliminating the chattering effects associated with a conventional sliding mode position controller. When the rotor resistance is varied with the temperature, the proposed rotor resistance observer with a sliding mode controller are effective in estimating the rotor resistance, load torque disturbances and tracking the rotor position.

碩士
國立臺灣科技大學
機械工程系
98
The system parameters of induction motor(IM) vary with different operating conditions. The temperature-dependent variation of the stator and rotor resistance, which induces a large estimation error on speed and flux, has been a critical issue for speed-sensorless control. On speed-sensorless control, the observer is as important as the controller. The noise immunity and real time estimation ability of Extended Kalman filter(EKF)-based observer lead to a popular application in the field of speed-sensorless control. However, the simultaneous estimation of stator and rotor resistance based on EKF in speed-sensorless control of IMs has not been done to the best of author's knowledge. A novel EKF-based estimation method is proposed for simultaneous estimation of stator and rotor resistance. The simultaneous estimation is achieved by an augmented state for the stator temperature dynamics. The broken-bar phenomenon of rotor can also be detected in the case we studied. Simulation results display promising robustness to variation of system parameters.

碩士
國立臺北科技大學
電機工程系研究所
98
Currently, most of Doubly-Fed Induction Generators(DFIGs) were controlled by the rotor voltage commands. This thesis directly inputs rotor current commands to control the real and imaginery powers of DFIGs. First, the vector control principle is used to develop the real power、imaginery power and capacitor voltage controls. In order to effectively control DFIGs, the model of DFIGs are transformed from the a-b-c frame to the d-q axis frame. Then both the PI linear control and Backstepping nonlinear control theories are adopted to realize the control of the real and imaginery powers. The PSCAD/EMTDC and Matlab/Simulink are used to simulate and verified the proposed PI control and Backstepping nonlinear control respectively. Meanwhile, the PSCAD/EMTDC and Matlab/Simulink are compared in the simulation chapter. The results confirm the performances of the proposed real power、imaginery power and capacitor voltage controllers

碩士
國立臺灣科技大學
機械工程系
104
The performance of sensorless control of induction motors (IMs) is dramat- ically affected by the variation of parameters such as rotor resistance especially at low speeds and heavy loads. A novel hybrid artificial neural network (HANN), including a cerebellar model adaptive controller (CMAC) and an adaptive linear element (ADALINE), is developed in this thesis to estimate the rotor resistance and the motor speed simultaneously. On the other hand, a self-tuning PI-type fuzzy logic controller (FLC) is used to achieve motor speed control based on the speed estimate. Experimental results show that the proposed sensorless speed con- trol strategy achieves accurate speed control even at low speed and under loaded conditions.

Quadrotors are aerial vehicles with a four motor-rotor assembly for generating lift and controllability. Their light weight, ease of design and simple dynamics have increased their use in aerial robotics research. There are many quadrotors that are commercially available or under development. Commercial off-the-shelf quadrotors usually lack the ability to be reprogrammed and are unsuitable for use as research platforms. The open-source code developed in this thesis differs from other open-source systems by focusing on the key performance road blocks in implementing high performance experimental quadrotor platforms for research: motor-rotor control for thrust regulation, velocity and attitude estimation, and control for position regulation and trajectory tracking. In all three of these fundamental subsystems, code sub modules for implementation on commonly available hardware are provided. In addition, the thesis provides guidance on scoping and commissioning open-source hardware components to build a custom quadrotor. A key contribution of the thesis is then a design methodology for the development of experimental quadrotor platforms from open-source or commercial off-the-shelf software and hardware components that have active community support. Quadrotors built following the methodology allows the user access to the operation of the subsystems and, in particular, the user can tune the gains of the observers and controllers in order to push the overall system to its performance limits. This enables the quadrotor framework to be used for a variety of applications such as heavy lifting and high performance aggressive manoeuvres by both the hobby and academic communities. To address the question of thrust control, momentum and blade element theories are used to develop aerodynamic models for rotor blades specific to quadrotors. With the aerodynamic models, a novel thrust estimation and control scheme that improves on existing RPM (revolutions per minute) control of rotors is proposed. The approach taken uses the measured electrical power into the rotors compensating for electrical loses, to estimate changing aerodynamic conditions around a rotor as well as the aerodynamic thrust force. The resulting control algorithms are implemented in real-time on the embedded electronic speed controller (ESC) hardware. Using the estimates of the aerodynamic conditions around the rotor at this level improves the dynamic response to gust as the low-level thrust control is the fastest dynamic level on the vehicle. The aerodynamic estimation scheme enables the vehicle to react almost instantaneously to aerodynamic changes in the environment without affecting the overall dynamic performance of the vehicle. To quantify the resulting improvements in maintaining a desired thrust setpoint using the proposed thrust modelling and control scheme over current state-of-the-art rotor speed control, static and dynamic flight tests are carried out in downdrafts and updrafts of varying strengths. In the static tests, the new scheme is able to determine the changes in axial gust thereby changing the speed of the rotor to maintain the desired thrust setpoint. The dynamic flight test is demonstrated by a path tracking experiment where a quadrotor is flown through an artificial wind gust and the trajectory tracking error measured. The proposed approach for thrust control demonstrably reduced tracking errors compared to the classical RPM rotor control. Non-linear dynamic models for the drag forces on individual rotors of a quadrotor are examined and a combined or lumped drag force model is derived. Combining this drag force model with measurements from the strapdown inertial measurement unit (IMU) and a complementary filter that uses barometer height estimates, the full body-fixed frame velocity measurements are obtained. Adding measurements from an inertial navigation system and a magnetometer, a coupled non-linear complementary filter in both the body-fixed and inertial frames is proposed. The resulting observer is a velocity aided attitude observer that provides estimates of both linear velocities in inertial and body-fixed frames and attitude of the vehicle. The observer is robust to GPS dropouts and can be used in indoor environments without an indoor navigation system such as Vicon motion capture system. A hierarchical control structure for quadrotors is proposed with high-level position/trajectory tracking control and velocity control, mid-level attitude control and low-level motor thrust control based on the time scale separation of each dynamic sublevel. The attitude error dynamics under the proposed attitude control law are shown to be non-autonomous. Using passivity based Lyapunov analysis and showing that the linear dynamics are uniformly completely observable (UCO), the attitude dynamics are shown to be locally exponentially stable. Under the proposed position/trajectory control law, the error dynamics form a block diagonal matrix with eigenvalues in the left half plane. Hence, the proposed position/trajectory tracking controller is locally exponentially stable. The proposed velocity controller which uses the estimated velocity is also shown to be asymptotically stable and its linear dynamics are uniformly completely observable. Hence by the notion of input-to-state stability, the quadrotor is exponentially stable under the proposed control laws. The dynamic properties (acceleration, jerk and snap) of the vehicle are used to algebraically determine feedforward terms (angular velocity and acceleration) which are used in the mid-level attitude controller to enable precise trajectory tracking.

碩士
崑山科技大學
電機工程研究所
98
A speed sensorless system is proposed for direct vector control of induction motor drives. In this thesis, based on a sliding mode stator current observer, a sliding mode rotor flux observer is adopted. Rotor flux is merely integrated from the control input of the current observer when the estimated current error approaches zero. In other words, the sliding mode observer is insensitive to motor parameters variations. In general, a PI current controller is often used in field oriented control scheme to produce the stator voltage command. It is time-consuming to tune the proportional control and integral control parameters of the PI current controller. A new current controller is used in this thesis. Feedback stator current information and tunning the PI control parameters are not required in the new current controller. Then, the aforementioned new current controller and the sliding mode rotor flux observer are applied to a speed sensorless induction motor drives for speed and position control. First, the proposed control scheme has evaluated by MATLAB/Simulink simulation toolbox. Then, a PC-based experimental system is constructed to test the performances of the overall system.

碩士
國立臺北科技大學
電機工程系
106
The main purpose of this paper is to propose a model based predictive current control with online inductance estimation for three-phase AC/DC converter. Because the traditional model based predictive current control is easily susceptible to inaccurate inductance parameters, and thereby affect system response and performance. The traditional model based predictive current control is improved by the estimation of the inductance. Finally, the switching state of the converter is predicted via the minimization of the cost function. It is worth mentioning that online inductance estimation does not need to add additional sensor in the traditional converter, though the parameters change will not affect the control performance. The method proposed in this thesis using Texas Instruments microprocessor controller TMS320F28377D. The digitized control is achieving by a software to confirm the validity of model based predictive current control method with online inductance estimation. In addition, the measured harmonics will meet the specifications of IEC61000-3-2 Class A.

The objective of this thesis is to contribute to Autonomous Underwater Vehicle (AUV) navigation by estimating the prevalent ocean currents and improving the path following guidance system. The Inertial Navigation System (INS) based localisation solution is vulnerable to uncertainties derived from double integration of the inherent errors within the INS acceleration measurements. This can be aided by the velocity measurement using the Doppler Velocity Log (DVL), but DVL aid is unavailable when the distance between the AUV to the seabed is larger than the DVL range. However, the vehicle’s velocity can be estimated by a model-aided observer which predicts a dynamic motion response of the vehicle. The benefits from using a more precise AUV model is compelling as the application of underwater vehicles expand into more complicated and harsher environments. In terms of the AUV motion model, however, the effect of current on the vehicle dynamics is often ignored when the AUV motion model is used for control, navigation and estimation. As a solution for this, an AUV dynamic model-based, nonlinear observer design is introduced, which is complemented with the development of an AUV dynamic model in nonuniform and unsteady current and the high-gain observer (HGO). The gain for the HGO is obtained by solving a Linear Matrix Inequality (LMI) representing the estimation error dynamic. The HGO is a robust tool for observer design and well-used in nonlinear feedback control, which has been studied for several decades. Motivated by the design method of the HGO, the current disturbance is considered as the uncertainties of the vehicle dynamic system, and current velocity is estimated in an indirect way. The current velocity is determined by calculating the differences between the vehicle velocities over the ground and the vehicle velocities through the water estimated by the model-based observer. The HGO based on the AUV dynamic model established in this research was validated using experimental data from a set of field manoeuvres using a Gavia class AUV and the performance was compared against other commonly used navigation methods. In terms of the path following problem, an accurate path following guidance system plays an important role for an AUV in oceanic surveys and exploration. The path-following guidance system includes a guidance law, an update law and a proportional and integral controller. This thesis presents a three-dimensional path following guidance logic which ensures the vehicle path converges into the predefined desired path. The desired straight and curved path re represented by using a Serret-Frenet frame which propagates along the curve. The path following guidance system, ‘PPNAPG (Pure Proportional Navigation and Pursuit Guidance)’ is developed by combining the pure proportional navigation guidance (PPNG) law and pursuit guidance (PG) law, which are widely used in the missile community. The performance of the proposed path-following guidance system, PPNAPG is validated via both simulation and experiment using the MUN (Memorial University of Newfoundland) Explorer AUV. One of the primary benefits of the nonlinear observer based on the AUV dynamic model and the path following guidance system is that it could be employed on any type of AUV plat forms without any elaboration. Furthermore, the proposed techniques require no additional sensors beside the typically available AUV navigation sensors such as global positioning, accelerometers and gyroscopes in the Initial Measurement Unit (IMU). Overall, this thesis suggests that the nonlinear observers based on an AUV dynamic model and the PPNAPG is an effective combination to estimate and compensate for the current and complete a path-following mission. These outcomes and methods enable other researchers and students in the field of AUV control and navigation systems to adapt and extend the methods to other AUV models without using an ADCP to measure the current. The insight gained from this study can also be of assistance to an oceanographic mission by optimising the guidance law to reduce mission completion time.

The main goal of this thesis is to develop practical digital controller architectures for multi-phase dc-dc converters utilized in low power (up to few hundred watts) and cost-sensitive applications. The proposed controllers are suitable for on-chip integration while being capable of providing advanced features, such as dynamic efficiency optimization, inductor current estimation, converter component identification, as well as combined dynamic current sharing and fast transient response. The first part of this thesis addresses challenges related to the practical implementation of digital controllers for low-power multi-phase dc-dc converters. As a possible solution, a multi-use high-frequency digital PWM controller IC that can regulate up to four switching converters (either interleaved or standalone) is presented. Due to its configurability, low current consumption (90.25 μA/MHz per phase), fault-tolerant work, and ability to operate at high switching frequencies (programmable, up to 10 MHz), the IC is suitable to control various dc-dc converters. The applications range from dc-dc converters used in miniature battery-powered electronic devices consuming a fraction of watt to multi-phase dedicated supplies for communication systems, consuming hundreds of watts. A controller for multi-phase converters with unequal current sharing is introduced and an efficiency optimization method based on logarithmic current sharing is proposed in the second part. By forcing converters to operate at their peak efficiencies and dynamically adjusting the number of active converter phases based on the output load current, a significant improvement in efficiency over the full range of operation is obtained (up to 25%). The stability and inductor current transition problems related to this mode of operation are also resolved. At last, two reconfigurable digital controller architectures with multi-parameter estimation are introduced. Both controllers eliminate the need for external analog current/temperature sensing circuits by accurately estimating phase inductor currents and identifying critical phase parameters such as equivalent resistances, inductances and output capacitance. A sensorless non-linear, average current-mode controller is introduced to provide fast transient response (under 5 μs), small voltage deviation and dynamic current sharing with multi-phase converters. To equalize the thermal stress of phase components, a conduction loss-based current sharing scheme is proposed and implemented.