This thesis focues on the realization of small size brushless DC fan motor driving circuit, adding the protection circuit of commutation to H bridge, in addition, the function of low current limiter, and slow rotation speed limiter are also implemented to the more stable rotation. With regard to the strategy of rotation speed control, we use speed feedback controller to slove noise problem which occurs in high frequency full speed excited and adopt thermistor accompanied with the voltage divided circuit to achieve speed control with temperature. Finally, for the sake of reducing the cost and shrinking the size of system, the design of sensorless mode is proposed and the rotation speed control system is realized under sensorless mode.

Sensorless speed estimation in induction machines (IMs) presents an attractive proposition for eliminating the need for physical speed measurement sensors and thus avoiding the associated reliability and cost issues, such as the requirement of extra wiring, careful mounting, maintenance and adjustment. In this thesis, the feasibility of utilising the stator current and power signals to establish spectral search based (SSB) sensorless speed estimation schemes in wound rotor induction machines (WRIMs) operating in extended slip and open-loop controlled conditions is investigated. The research is performed on three different industrial WRIM designs. The thesis first investigates the spectral content of WRIM electrical and mechanical signals with the principal aim of identifying spectral patterns that can facilitate the development of real-time sensorless speed estimation. The examination is based on detailed harmonic models of the considered machine designs as well as experimental results obtained from tests performed on laboratory test rigs. A generalised theoretical analysis of the possible spectral content of machine signals that enables the derivation of closed form analytical expressions linking individual spectral frequencies to rotor speed is also undertaken. The results demonstrate that it is possible to clearly identify speed dependent components in the stator current and power signals and map the boundaries of the narrowbands maximised by these for extended slip and open-loop operating conditions. To enable improvement in attainable real time SSB estimation rates a dichotomous search algorithm real-time spectral processing method was employed for frequency tracking in this research. The algorithm performance is evaluated in real-time tests performed on a measured steady-state laboratory machine stator current and power signals. The results demonstrate that the dichotomous routine provides an inherent advantage in the frequency estimation rate without compromising the estimation accuracy and can therefore enable significant estimation rate improvement in SSB speed estimation algorithms. Novel sensorless speed SSB estimation techniques are then proposed for WRIM operation in extended slip and voltage/frequency controlled conditions. The algorithms utilise the reported analysis of electrical signals and are separately defined for each assessed operation mode and the stator current, phase power and three-phase power signals. It is shown that, in principle, power signal based estimation algorithms can offer an inherent capability of estimation rate reduction. A novel adaptive sliding window algorithm is defined for open-loop operating conditions that enable estimation in a wide operating speed range while minimising the potential for undesirable overlap with PWM harmonics. The proposed algorithms have been verified and their performance limitations assessed in real-time experiments on three different industrial WRIM designs. It is shown that reliable real-time speed estimation in steady-state and transient operating conditions is possible at an improved estimation rate while maintaining a low estimation error.

Switched reluctance motors (SRMs) are promising candidates for electric vehicles due to lower manufacturing costs, higher efficiency, and robustness operation in a harsh envi-ronment. For accurate control of the SRM, the real-time rotor position is needed for phase computation. To obtain position information, position-sensorless control techniques have been developed to take the role of position sensors in commercial SRM drives for cost reduction or sensor-fault tolerance capability. Nowadays, the position-sensorless control of SRMs still suffers from a technical problem: the dependence on magnetic characteris-tics. Existing position estimation algorithms often require time-consuming offline meas-urement of magnetic parameters, limiting the broad applications due to the low generality. It is therefore of great significance to develop universal position-sensorless control tech-niques with less magnetic parameter dependence. Zero- and low-speed position-sensorless control of the SRM needs high-frequency in-jection into the idle phase to measure the stator inductance. Rotor position is often esti-mated from the prestored inductance lookup table but is replaced by a new regional phase-locked loop (RPLL) with a self-commissioning process in this thesis. The modeling of the unsaturated stator inductance can be established automatically via the pulse voltage injection at the initial stage without offline testing. The RPLL embedded with a three-phase heterodyne design can estimate the full-cycle rotor position from the idle-phase in-ductance based on the unsaturated inductance model. The proposed low-speed position estimator can also realize robust sensorless control in four-quadrant operation and magnet-ic saturation conditions without complicated magnetic characteristics. Besides, local sta-bility of the position estimator is proved, and an optimized parameter design scheme is given. Although pulse voltage injection offers accurate position estimation in low-speed op-eration, the induced pulse current results in additional copper loss and torque ripples. This problem is overcome in the thesis by regulating the magnitude of induced current at a minimal level. The induced current regulator is designed as a terminal sliding-mode con-troller that adjusts the injection voltage online over the whole idle-phase period. Proper control parameter selection based on the convergence analysis and stability proof ensures robust control performance against parameter uncertainties. The proposed pulse injection scheme combined with the RPLL can guarantee accurate position estimation while reduc-ing copper losses and torque ripples significantly. Due to the shortened idle-phase duration when the rotor speed increases, pulse injec-tion methods are infeasible for high-speed position estimation. To solve the problem, this thesis proposes a nonlinear observer based on feature position estimation in conduction phases for high-speed sensorless control. A self-commissioning method is adopted to cap-ture a two-dimensional flux linkage curve at a feature position, which avoids offline measurement of the complete three-dimensional characteristics. However, the estimated feature position has low resolution, and its estimation accuracy is degraded by nonideal flux linkage errors. To improve the sensorless control performance, a nonlinear state ob-server using online Fourier series is then designed to eliminate disturbances in position es-timation. Parameter design based on a small-signal analysis is also given to guarantee ac-curate position and speed estimation. High-speed position-sensorless control is further simplified using a new quadrature flux estimator without using any flux linkage characteristics. The method requires neither offline measurement nor online self-commissioning. This advantage is realized by adopt-ing a speed-adaptive bandpass filter to extract the fundamental flux linkage. A three-phase phase-locked loop is then used to estimate the rotor position from the orthogonal flux linkage signals without a priori knowledge of the SRM magnetic characteristics. The magnetic-parameter-free position estimation can facilitate the application of sensorless control in a general-purpose SRM converter. A wide-speed range position estimation scheme is realized by combining both the low-speed and high-speed position estimation approaches. Consequently, a universal posi-tion-sensorless control scheme is proposed in the thesis, covering the full-speed range and not requiring offline measurement effort. The proposed position estimation schemes are verified on a 5.5 kW 12/8 SRM test bench. / Thesis / Doctor of Philosophy (PhD)

No description available.

With the increasing exploration of space and widespread use of communication tools worldwide, near-ground satellite communication has emerged as a promising tool in various fields such as aerospace, military, and microscopy. However, the presence of air and water in the atmosphere causes distortion in the light signal, and thus, it is essential for the ground base to retrieve the original signal from the distorted light signal sent from the satellite. Traditionally, Shack-Hartmann sensors or charge-coupled devices are integrated in the system for distortion measurement. In our pursuit of a cost-effective system establishment with optimal performance and enhanced response speed, sensors and charge-coupled devices have been replaced by a photodiode and a single mode fiber in this project. Since the system has limited observation capability, it requires a powerful controller for optimal performance. To address this issue, we have implemented an off-policy reinforcement learning framework, the soft actor-critic, in the adaptive optics system controller. This integration results in a model-free online controller capable of mitigating wavefront distortion. The soft actor-critic controller processes the acquired data matrix from the photodiode and generates a two-dimensional array control signal for the deformable mirror, which corrects the wavefront distortion induced by the atmosphere, and refocusing the signal to maximize the incoming power. The parameters of the soft actor-critic controller have been tuned to achieve optimal system performance. Simulations have been conducted to compare the performance of the proposed controller with respect to wavefront sensor-based methods. The training and verification of the proposed controller have been conducted in both static and semi-dynamic atmospheres, under different atmospheric conditions. Simulation results demonstrate that, in severe atmospheric conditions, the adaptive optics system with the soft actor-critic controller achieves more than 55% and 30% Strehl ratio on average in static and semi-dynamic atmospheres, respectively. Furthermore, the distorted wavefront's power can be concentrated at the center of the focal plane and the fiber, providing an improved signal.

Este trabalho apresenta através de simulação um estudo comparativo de estimadores de velocidade de motor de indução trifásico por meio de observadores de estado e da técnica do filtro de Kalman. É realizada uma análise comparativa de desempenho das estratégias de estimação determinísticas e estocásticas, com observadores adaptativos e estimadores baseados na teoria do filtro de Kalman estendido, respectivamente. A realização do trabalho visa a constatação dos procedimentos de elaboração, de operação e de aplicação destas técnicas de estimação usando um exemplo real com fins de ilustrar o ensino de controle e acionamento de máquinas elétricas. As simulações foram realizadas através do Matlab/Simulink com a utilização das ferramentas do Power System Blockset (PSB) e o algoritmo dos estimadores é escrito em programa Matlab e executado por uma função S-Function. Os resultados de simulação demonstram a eficiência de cada um dos estimadores propostos, no que se refere ao comportamento transitório, robustez a ruídos e variações nos parâmetros do motor. / This works presents through of the simulation a comparative study of the sensorless of speed estimation of induction three-phase motor using state observer and Kalman filter. A comparative analysis of the performance of the deterministic and stochastic estimation strategies using adaptive observers and estimators based on extended Kalman filter was realized. The work aims to verify the procedure of the elaboration, operation and application of such estimation techniques using a real example to illustrate the teaching of the control and driving of electric machines. The simulations where performed using Matlab/Simulink with Power System Blockset (PSB) toolboxes and the estimators are programmed as S-Function Matlab. The results indicate the effectiveness of the proposed estimators, according to the transient behavior, robustness to noise and ability to handle parametric variations.

Este trabalho tem por objetivo estudar e avaliar uma técnica de determinação de posição inicial de rotor em máquinas síncronas de ímã permanente de superfície. A técnica de determinação de posição inicial é baseada na aplicação de pulsos ao motor. É proposto também um algoritmo de ajuste automático desses pulsos de forma a criar um mecanismo genérico de determinação de posição inicial de ângulo de rotor para o tipo de máquina em estudo. Simulações são realizadas de forma a garantir funcionamento correto do algoritmo que foi implementado em código C com matemática de ponto fixo. A implementação foi realizada utilizando-se um microcontrolador comercial de baixo custo que não possui hardware para aritmética de ponto flutuante. Um descritivo detalhado da implementação, do sistema de testes e resultados são apresentados ao longo do texto. / This work aims the study and evaluation of a rotor initial angle estimation technique in surface mounted permanent magnet synchronous machine. The technique of the rotor initial angle estimation is based on pulse injection to the motor. It is also proposed in this work an automatic pulse adjustment algorithm in order to create a generic mechanism to estimate rotor initial angle for the machine type under study. Simulations are performed in order to ensure the proper functionality of the algorithm which was implemented in C code with fixed point mathematics. The implementation was performed using a comercial low cost microcontroller which does not have floating point arithmetic capability. A detailed description of the implementation, test system and results are presented in this text.

O presente trabalho trata do desenvolvimento de um sistema de controle vetorial para máquinas elétricas síncronas de ímã permanente (MSIP), com forma de onda da força contra eletromotriz (FCEM) não senoidal, sem a utilização de sensor de posição angular do eixo. O sistema de controle é desenvolvido utilizando a transformação não-senoidal dqx, que exige a todo instante o conhecimento da posição do rotor, assim aplica-se um estimador de posição baseado nas medidas elétricas e no modelo matemático da máquina elétrica utilizando o filtro de Kalman juntamente com PLLs. Abordam-se a modelagem matemática da máquina, as técnicas de controle sem sensor tradicionais e as abordagens de controle de alto desempenho sem o uso de sensor de posição. Mostra-se o sistema proposto bem como os resultados da sua aplicação em ambiente simulado e por meio de testes práticos em bancada, mostrando o comportamento dinâmico da máquina síncrona. / This work deals with the development of a vector control system for permanent magnet synchronous machines (PMSM), with non-sinusoidal back electromotive force (Back EMF) waveforms, widely known as the BLDC machine, without shaft angular position sensor. The control system is developed using the non-sinusoidal transformation dqx, which demands constant knowledge of the shaft\'s angular position. This way, a position estimator is applied, based solely on electrical measurements and the machines mathematical model applying the Kalman filter and PLLs. Thus, the machines mathematical modelling, and the sensorless control and estimation approaches are reviewed. The developed system is explained, along with the results obtained trough simulations and practical tests, demonstrating the dinamic behavior of the PMSM.

Este trabalho apresenta através de simulação um estudo comparativo de estimadores de velocidade de motor de indução trifásico por meio de observadores de estado e da técnica do filtro de Kalman. É realizada uma análise comparativa de desempenho das estratégias de estimação determinísticas e estocásticas, com observadores adaptativos e estimadores baseados na teoria do filtro de Kalman estendido, respectivamente. A realização do trabalho visa a constatação dos procedimentos de elaboração, de operação e de aplicação destas técnicas de estimação usando um exemplo real com fins de ilustrar o ensino de controle e acionamento de máquinas elétricas. As simulações foram realizadas através do Matlab/Simulink com a utilização das ferramentas do Power System Blockset (PSB) e o algoritmo dos estimadores é escrito em programa Matlab e executado por uma função S-Function. Os resultados de simulação demonstram a eficiência de cada um dos estimadores propostos, no que se refere ao comportamento transitório, robustez a ruídos e variações nos parâmetros do motor. / This works presents through of the simulation a comparative study of the sensorless of speed estimation of induction three-phase motor using state observer and Kalman filter. A comparative analysis of the performance of the deterministic and stochastic estimation strategies using adaptive observers and estimators based on extended Kalman filter was realized. The work aims to verify the procedure of the elaboration, operation and application of such estimation techniques using a real example to illustrate the teaching of the control and driving of electric machines. The simulations where performed using Matlab/Simulink with Power System Blockset (PSB) toolboxes and the estimators are programmed as S-Function Matlab. The results indicate the effectiveness of the proposed estimators, according to the transient behavior, robustness to noise and ability to handle parametric variations.

O presente trabalho trata do desenvolvimento de um sistema de controle vetorial para máquinas elétricas síncronas de ímã permanente (MSIP), com forma de onda da força contra eletromotriz (FCEM) não senoidal, sem a utilização de sensor de posição angular do eixo. O sistema de controle é desenvolvido utilizando a transformação não-senoidal dqx, que exige a todo instante o conhecimento da posição do rotor, assim aplica-se um estimador de posição baseado nas medidas elétricas e no modelo matemático da máquina elétrica utilizando o filtro de Kalman juntamente com PLLs. Abordam-se a modelagem matemática da máquina, as técnicas de controle sem sensor tradicionais e as abordagens de controle de alto desempenho sem o uso de sensor de posição. Mostra-se o sistema proposto bem como os resultados da sua aplicação em ambiente simulado e por meio de testes práticos em bancada, mostrando o comportamento dinâmico da máquina síncrona. / This work deals with the development of a vector control system for permanent magnet synchronous machines (PMSM), with non-sinusoidal back electromotive force (Back EMF) waveforms, widely known as the BLDC machine, without shaft angular position sensor. The control system is developed using the non-sinusoidal transformation dqx, which demands constant knowledge of the shaft\'s angular position. This way, a position estimator is applied, based solely on electrical measurements and the machines mathematical model applying the Kalman filter and PLLs. Thus, the machines mathematical modelling, and the sensorless control and estimation approaches are reviewed. The developed system is explained, along with the results obtained trough simulations and practical tests, demonstrating the dinamic behavior of the PMSM.