This thesis presents different state estimation techniques for speed sensorlees field oriented control of induction motors. The theoretical basis of each algorithm is explained in detail and its performance is tested with simulations and experiments individually. First, a stochastical nonlinear state estimator, Extended Kalman Filter (EKF) is presented. The motor model designed for EKF application involves rotor speed, dq-axis rotor fluxes and dq-axis stator currents. Thus, using this observer the rotor speed and rotor fluxes are estimated simultaneously. Different from the widely accepted use of EKF, in which it is optimized for either steady-state or transient operations, here using adjustable noise level process algorithm the optimization of EKF has been done for both states / the steady-state and the transient-state of operations. Additionally, the measurement noise immunity of EKF is also investigated. Second, Unscented Kalman Filter (UKF), which is an updated version of EKF, is proposed as a state estimator for speed sensorless field oriented control of induction motors. UKF state update computations, different from EKF, are derivative free and they do not involve costly calculation of Jacobian matrices. Moreover, variance of each state is not assumed Gaussian, therefore a more realistic approach is provided by UKF. In this work, the superiority of UKF is shown in the state estimation of induction motor. Third, Model Reference Adaptive System is studied as a state estimator. Two different methods, back emf scheme and reactive power scheme, are applied to MRAS algorithm to estimate rotor speed. Finally, a flux estimator and an open-loop speed estimator combination is employed to observe stator-rotor fluxes, rotor-flux angle and rotor speed. In flux estimator, voltage model is assisted by current model via a closed-loop to compensate voltage model&rsquo / s disadvantages.

The main focus of the study is the implementation of techniques regarding flux estimation and rotor speed estimation by the use of sensorless closed-loop observers. Within this framework, the information about the mathematical representation of the induction motor, pulse width modulation technique and flux oriented vector control techniques together with speed adaptive flux estimation &ndash / a kind of sensorless closed loop estimation technique- and Kalman filters is given. With the comparison of sensorless closed-loop speed estimation techniques, it has been attempted to identify their superiority and inferiority to each other by the use of simulation models and real-time experiments. In the experiments, the performance of the techniques developed and used in the thesis has been examined under extensively changing speed and load conditions. The real-time experiments have been carried out by the use of TI TMS320F2812 digital signal processor, XILINX XCS2S150E Field Programmable Gate Array (FPGA), control card and the motor drive card Furthermore, Matlab &ldquo / Embedded Target for the TI C2000 DSP&rdquo / and &ldquo / Code Composer Studio&rdquo / software tools have been used. The simulations and experiments conducted in the study have illustrated that it is possible to increase the performance at low speeds at the expense of increased computational burden on the processor. However, in order to control the motor at zero speed, high frequency signal implementation should be used as well as a different electronic hardware.

In this thesis, field oriented control of permanent magnet synchronous motors using three-level neutral-point-clamped inverter is studied. Permanent magnet synchronous motors are used in high performance drive applications. In this study, the permanent magnet synchronous motor is fed by three-level neutral-point-clamped inverter. For three-level neutral-point-clamped inverter different space vector modulation algorithms, which are reported in literature, are analyzed and compared via computer simulations. The voltage balance on dc-link capacitors is also analyzed and a software control method is implemented in conjunction with the space vector PWM modulation, utilized. Nonlinear effects such as dead-time, semiconductor voltage drop and delays in gate drive circuitries also present in neutral-point-clamped inverter. The effects of these nonlinearities are studied and a compensation method for these nonlinear effects is proposed. The theoretical results are supported with computer simulations and verified with experimental results.

This work focuses on speed estimation techniques for sensorless closed-loop speed control of an induction machine based on direct field-oriented control technique. Details of theories behind the algorithms are stated and their performances are verified by the help of simulations and experiments. The field-oriented control as the vector control technique is mainly implemented in two ways: indirect field oriented control and direct field oriented control. The field to be oriented may be rotor, stator, or airgap flux-linkage. In the indirect field-oriented control no flux estimation exists. The angular slip velocity estimation based on the measured or estimated rotor speed is required, to compute the synchronous speed of the motor. In the direct field oriented control the synchronous speed is computed with the aid of a flux estimator. Field Oriented Control is based on projections which transform a three phase time and speed dependent system into a two co-ordinate time invariant system. These projections lead to a structure similar to that of a DC machine control. The flux observer used has an adaptive structure which makes use of both the voltage model and the current model of the machine. The rotor speed is estimated via Kalman filter technique which has a recursive state estimation feature. The flux angle estimated by flux observer is processed taking the angular slip velocity into account for speed estimation. For closed-loop speed control of system, torque, flux and speed producing control loops are tuned by the help of PI regulators. The performance of the closed-loop speed control is investigated by simulations and experiments. TMS320F2812 DSP controller card and the Embedded Target for the TI C2000 DSP tool of Matlab are utilized for the real-time experiments.

Made available in DSpace on 2016-12-12T17:38:36Z (GMT). No. of bitstreams: 1 rafael Campos resumo.pdf: 28958 bytes, checksum: c0306d4f10c2c1dab1c5e8750f4a0ea1 (MD5) Previous issue date: 2008-07-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this work is to study the rotor flux vector control applied to a single-phase induction motor drive. Initially, a mathematical model of the motor will be derived. The motor equations will be transformed to the stationary reference frame so that the angular dependency due to the asymmetry of the motor variables is eliminated. Then is discussed that single-phase induction motor can be viewed as a two-phase system. A mathematical model to derive the motor parameters is presented. The next step is to analyze the rotor flux vector control, pointing out the need for a symmetry transformation of the motor parameters. Two control methods are presented: direct rotor flux control and indirect rotor flux control. Theses control methods are validated through numerical simulations. Experimental analyses making use of a digital signal processor are carried out. The results obtained show the good dynamic response when the vector control method is applied to a single-phase induction motor drive system. / Este trabalho tem por objetivo estudar o acionamento do motor de indução utilizando o método de controle vetorial por fluxo de rotor. Inicialmente, desenvolvido o modelo matemático do motor de indução monofásico transformado o eixo estacionário para que seja eliminada a dependência angular das variáveis do devido à assimetria dos parâmetros do motor. É observado que o motor monofásico pode ser apresentado em configuração bifásica. Em seguida, um estudo de netrização do motor é realizado. O controle vetorial é analisado na seqüência, observando a necessidade de simetria dos parâmetros do motor para que haja um controle o do motor. São considerados dois métodos: controle direto do fluxo de rotor e indireto do fluxo de rotor. Analisa-se, também, o comportamento do controle de simulações numéricas Na seqüência,implementa-se experimentalmente o controle utilizando um processador digital de sinais. Os resultados obtidos mostram que o estudado ao ser aplicado ao motor de indução monofásico apresenta uma boa ta dinâmica para o sistema, tanto para método direto quanto para o método indireto.

An optimization of a servo system for a satellite antenna system wasperformed. A brushless DC motor with an angle encoder was used, whoseangular velocity had to be controlled with great precision. Specializedhardware was used to implement field oriented control to directlycontrol the torque and magnetic flux of the motor. Multiple velocitycontrollers were tested for the closed servo system, which controlledthe amplitude of the motor current to achieve the given reference valuefor the angular velocity. A PI regulator was tested and evaluated aslacking in terms of precision, which was caused by low resolution of theerror signal for the angular velocity of the motor. This in turn wascaused by low resolution of the angular velocity measurement. Theanguluar velocity error signal was filtered to combat this, and a feedforward method was implemented where the reference value for the angularvelocity was integrated over time to generate a reference value for theangular position. Since the angular position could be measured withbetter precision, a better error signal based on the angular positioncould be generated which was then used as input to another regulatorwhose output signal was added to the original regulator to increase theaccuracy of the system significantly. The two regulator output signalswere then weighted based on the reference value for the angularvelocity. This was done because the two regulators performed well fordifferent velocity bands, which this method took into consideration. Thefinal servosystem fullfilled the set requirements by a good margin.

This thesis contains introduction to PMS motor control using development board ZedBoard with Xilinx Zynq-7000 SoC. After that, there is a description of development environment Vivado and other modules. Finally, it contains description or created modules in Vivado environment which were combined together with peripheral drivers to demonstrate field oriented motor control algorithm of small PMS motor.

In diesem Beitrag wird ein analytischer Ausdruck für die Bestimmung des Sollwerts der Läuferflussverkettung einer Asynchronmaschine (ASM) bei der feldorientierten Regelung vorgestellt. Dieser Wert wird durch das Lösen des Wirkungsgradoptimierungsproblems für jeden Betriebspunkt hergeleitet. Bei der Berechnung werden die Begrenzung der Spannungen sowie der Ströme als Nebenbedingungen in Betracht gezogen. Dieser Algorithmus eignet sich für industrielle Anwendungen, aber auch für Tranktionsantriebe, die mit ASM betrieben werden. / In this contribution, an analytic expression for the reference value of the flux linkage of an induction machine during field oriented control is proposed. This value results from solving the efficiency optimization problem of the ASM at each operational point. The restrictions on the motor voltages and currents are also considered in the optimization problem as constraints.The proposed method is suitable for industrial applications such as electric cars equipped with induction motors.

This thesis demonstrates a practical implementation of a sensorless permanent magnet synchronousmotor (PMSM) drive for vehicle propulsion. The main design parameters and overall properties of themotor drive are derived for the case of an on-board electric powertrain as a substitute to the lift shuttle indownhill (DH) mountain biking.The theory behind field oriented control (FOC) for sensorless PMSMs is analyzed in some detail.Controller-inverter hardware and software are designed and prototyped in accordance with the deriveddesign parameters. Initial tuning and testing in a test bench environment is described. The powertrain isfinally installed on a test bike and tested on an incline. It is found that the performance of the controllerinvertercomplies with the target design parameters.

The objective of the dissertation is to develop simplified analytical models for typical linear-motion and rotary-motion energy-conversion systems under active DC excitation without tedious numerical-simulation effort, and provide practical implementation of the models in optimal-design and thermal-protection aspects. The model of a vacuum automatic circuit recloser (a typical linear-motion system under DC excitation) is first developed in the form of a non-linear discontinuous eighth-order dynamic system. The model is then used to simulate the transient mechanical and electromagnetic performance during the opening and closing movements of the recloser. Such a model is not found in the literature. Although the model is based on certain simplifying assumptions, the result is validated by high-speed-camera measurements. In addition, the impact of key design variables is explored, based on which an improved recloser design is proposed, and helps to optimize capital and production costs without degrading performance. Further analytical investigation is carried out in modeling an inverter-fed induction motor (IM) (a typical rotary-motion system) with active DC injection. The IM is closed-loop controlled via two popular motor-control algorithms, namely, the direct-torque-control (DTC) algorithm and field-oriented-control (FOC) algorithm. Quantitative relationships between the changes of various machine variables during the active DC excitation are provided in the theoretical analysis. The developed DC-injection model is further simplified for practical implementation. The developed IM model under DC injection results in practical ways to excite a proper amount of DC current directly or indirectly into IM stator windings via different closed-loop motor-control algorithms. In a DTC motor-drive system, the modeling work makes it possible to excite the DC current indirectly inside the motor by superimposing a stator-flux-linkage-bias command in the flux-control loop or a torque-ripple command in the torque-control loop. The proposed flux-linkage-injection and torque-injection methods are the first novel efforts to implement the DC-signal-injection method in a DTC motor-drive system. In addition, the analysis carried out in a standard FOC drive system brings about an improved DC-current-injection approach: the torque ripple in this method is significantly mitigated compared to all existing DC-injection methods in FOC systems. The proposed DC-injection methods, either in a DTC or an FOC system, lead to a simple, low-cost, accurate, and non-invasive thermal-monitoring scheme for closed-loop-controlled IMs, where the stator temperature is indirectly estimated from stator resistance. Furthermore, considering inverter non-idealities, there is a challenge for a typical inverter drive to accurately estimate the DC component of motor terminal voltages. The existing methods are extended to provide a complete study of the real-time signal-processing technique for both DTC and FOC algorithms, and are finally implemented in a custom-built programmable motor-drive system. The experimental results demonstrate that the proposed technique gives accurate and robust stator-temperature estimation, regardless of the operating conditions and cooling modes. The analytical modeling method for the linear-motion and rotary-motion energy-conversion systems can be further extended to other power devices with similar mechanisms, and implemented in optimal design, control, and thermal-protection areas.