Os motores de indução trifásicos são largamente usados em vários setores da indústria. O dimensionamento da potência adequada de um motor de indução ou assíncrono trifásico, em função do comportamento das cargas acopladas ao eixo, continua em alguns casos impreciso pela falta de conhecimento mais completo do comportamento das cargas. A proposta deste trabalho consiste na utilização de sistemas Fuzzy como uma alternativa aos métodos tradicionais para levantamento do comportamento de carga e, em processos de controle, onde há a necessidade de conhecimento do comportamento do conjugado aplicado ao eixo do motor, enfocando diversos tipos de cargas encontrados em indústrias. Resultados de simulações são apresentados para validar a proposta deste trabalho. / The three phase induction motors are widely used in all industrial sectors. The selection procedure of the motor for a particular application is sometimes inaccurate due to the lack of complete knowledge about the load connected to its shaft. The proposal of this work consists of using Fuzzy system as an alternative tool to the classical methods for extraction of the load behavior and, in control process, where knowledge of the torque behavior applied to the motor shaft are need, focusing several types of loads found in industries. Simulation results are presented to validate the proposal of this work.

<p>The importance of control systems and diagnostics in vehicles are increasing and has resulted in several new methods to calculate better control signals. The performance can be increased by calculating these signals close to optimum, but that also require more and precise information regarding the system.</p><p>One of the wanted control signals are the crankshaft torque and the thesis presents two different methods to estimate this torque using engine speed variations. These methods are Modeling of the Crankshaft and Frequency Analysis. The methods are evaluated and implemented on for a four cylinder SAAB engine. Measurements are made in an engine test cell as well as a vehicle.</p><p>The results show that the Modeling of the Crankshaft method does not produce a satisfying estimation, with a difference of about 200% between estimated and calculated torque. On the other hand, the Frequency Analysis provides an accurate estimation of both mean and instantaneous indicated torque, with a maximum difference of ±20% between estimated and calculated torque.</p>

The importance of control systems and diagnostics in vehicles are increasing and has resulted in several new methods to calculate better control signals. The performance can be increased by calculating these signals close to optimum, but that also require more and precise information regarding the system. One of the wanted control signals are the crankshaft torque and the thesis presents two different methods to estimate this torque using engine speed variations. These methods are Modeling of the Crankshaft and Frequency Analysis. The methods are evaluated and implemented on for a four cylinder SAAB engine. Measurements are made in an engine test cell as well as a vehicle. The results show that the Modeling of the Crankshaft method does not produce a satisfying estimation, with a difference of about 200% between estimated and calculated torque. On the other hand, the Frequency Analysis provides an accurate estimation of both mean and instantaneous indicated torque, with a maximum difference of ±20% between estimated and calculated torque.

Os motores de indução trifásicos são largamente usados em vários setores da indústria. O dimensionamento da potência adequada de um motor de indução ou assíncrono trifásico, em função do comportamento das cargas acopladas ao eixo, continua em alguns casos impreciso pela falta de conhecimento mais completo do comportamento das cargas. A proposta deste trabalho consiste na utilização de sistemas Fuzzy como uma alternativa aos métodos tradicionais para levantamento do comportamento de carga e, em processos de controle, onde há a necessidade de conhecimento do comportamento do conjugado aplicado ao eixo do motor, enfocando diversos tipos de cargas encontrados em indústrias. Resultados de simulações são apresentados para validar a proposta deste trabalho. / The three phase induction motors are widely used in all industrial sectors. The selection procedure of the motor for a particular application is sometimes inaccurate due to the lack of complete knowledge about the load connected to its shaft. The proposal of this work consists of using Fuzzy system as an alternative tool to the classical methods for extraction of the load behavior and, in control process, where knowledge of the torque behavior applied to the motor shaft are need, focusing several types of loads found in industries. Simulation results are presented to validate the proposal of this work.

No description available.

In this thesis, high performance torque and speed control for a surface-mounted permanent magnet synchronous machine (PMSM) is designed, simulated and implemented. A three-phase two-level pulse width modulation voltage-source inverter (PWM-VSI) with power MOSFETs is used to feed the PMSM. The study has three objectives. The first is to compensate the voltage disturbance caused by nonideal characteristics of the voltage-source inverter (VSI). The second is to decouple the coupled variables in the synchronous reference frame model of the PMSM. The last is to design a load torque estimator in order to increase the disturbance rejection capability of the speed control. The angular acceleration required for load torque estimation is extracted through a Kalman filter from noisy velocity measurements. Proposed methods for improved torque and speed control performance are verified through simulations and experimental tests. The drive system is modeled in Matlab/Simulink, and control algorithms are developed based on this model. The experimental drive system comprises a three-phase VSI and a 385 W surface-mounted PMSM. Control algorithms developed in the study have been implemented in a digital signal processor (DSP) board and tested comprehensively. With the use of the proposed methods, a considerable improvement of torque and speed control performance has been achieved.

Stator current spectral analysis techniques are usually used to detect rotor faults in induction machines. Magnetic field anomalies in the airgap due to the rotor faults result in characteristic side-band harmonic components in the stator current spectrum, which can be measured as rotor fault signatures. A position-varying load torque oscillation at multiples of the rotational speed, however, has exactly the same effect. Stator current harmonics due to a load torque oscillation often obscure and even overwhelm rotor eccentricity fault detection since the magnitude of load oscillation induced harmonics is usually much larger. Although previous research has suggested some methods to differentiate between these two effects, most of them rely heavily on the accurate estimation of motor parameters. The objective of this research is to develop a far more practical and computationally efficient method to detect rotor faults effectively in the presence of a load torque oscillation. A significant advantage of the proposed scheme is that it does not need any knowledge of motor parameters. The normalized negative sequence information induced by a mixed rotor eccentricity in the stator current or terminal voltage space vector spectra, serves as a reliable rotor fault indicator to eliminate load oscillation effects. Detailed airgap magnetic field analysis for an eccentric motor is performed and all machine inductance matrices as well as their derivatives are reformulated accordingly. Careful observation of these inductance matrices provides a fundamental understanding of motor operation characteristics under a fault condition. Simulation results based on both induction motor dynamic model and Maxwell 2D Finite Element Model demonstrate clearly the existence of the predicted rotor fault indicator. Extensive experimental results also validate the effectiveness and feasibility of the proposed detection scheme.

The purpose of this disertation is to introduce and demonstrate a new approach to robust control of AC electrical drives. The proposed robust control method takes advantage of a nonlinear nature of AC motor d-q equations to construct self-scheduled LPV stator current controller. The benefit of this approach is in maitaining the robustness without any increase in conservatism of the H infinity controller. The resulting controller achieves fast and consistent response in the entire range of operating speeds. Rejection of the load torque disturbance is achieved with nonparametric H infinity speed controller in the outter loop of the cascade structure. The combination of LPV current controller and H infinity speed controller was verified on real-time simulation platform dSPACE ds1103. Simulation results for both types of AC motors (PMSM and IM) shows that the proposed solution is not only robust with respect to operating speeds but also impervious to wide range of load disturbance values.

Les entraînements électriques à base de machine asynchrone sont largement utilisés dans les applications industrielles en raison de leur faible coût, de leurs performances et de leur robustesse. Cependant, des modes de fonctionnement dégradés peuvent apparaître durant la vie de la machine. L'une des raisons principales de ces défaillances reste les défauts de roulements à billes. Afin d'améliorer la sûreté de fonctionnement des entraînements, des schémas de surveillance peuvent être mis en place afin d'assurer une maintenance préventive. Ce travail de thèse traite de la détection et du diagnostic des défauts mécaniques et plus particulièrement des défauts de roulements dans une machine asynchrone. Généralement, une surveillance vibratoire peut être mise en place. Cette méthode de surveillance est cependant souvent chère du fait de la chaîne de mesure. Une approche, basée sur l'analyse et le traitement des courants statoriques, est alors proposée, afin de suppléer à l'analyse vibratoire. L'étude est basée sur l'existence et la caractérisation des effets des oscillations du couple de charge sur les courants d'alimentation. Un schéma de détection est alors introduit pour détecter différents types de défauts de roulements. De plus, des variables mécaniques, telles que la vitesse ou le couple, sont également reconstruites afin de fournir une indication sur la présence de défauts de roulements. Par ailleurs, un diagnostic des modulations des courants statoriques est proposé, en régime permanent et en régime transitoire, quel que soit le rapport entre les fréquences porteuse et modulante. Les méthodes étudiées sont la transformée de Hilbert, la transformée de Concordia, l'amplitude et la fréquence instantanées ainsi que la distribution de Wigner-Ville. / Asynchronous drives are widely used in many industrial applications because of their low cost, high performance and robustness. However, faulty operations may appear during the lifetime of the system. The most frequently encountered faults in asynchronous drives come from rolling bearings. To improve the availability and reliability of the drives, a condition monitoring may be implemented to favor the predictive maintenance. This Ph.D. thesis deals with detection and diagnosis of mechanical faults, particularly rolling bearings defects in induction motors. Traditionally, bearing monitoring is supervised using vibration analysis. Measuring such quantities is often expensive due to the measurement system. An other approach, based on stator current analysis, is then proposed. The characterization of load torque oscillation effects on stator currents is studied. A detection scheme is then proposed to detect several types of bearing faults. Moreover, mechanical variables, such as rotating speed or torque, are estimated in order to detect bearings defects. In addition, a diagnosis of stator currents modulations is proposed, in steady and transient state, whatever the career and modulation frequencies. Hilbert transform, Concordia transform, instantaneous amplitude and frequency are studied. The Wigner-Ville distribution is used in transient state.

[pt] A avaliação experimental de modelos de plasticidade incremental e a predição da vida à fadiga sobre cargas combinadas requer o uso de máquinas de testes multiaxiais. Neste trabalho é desenvolvida uma máquina tração-torção (MTT) para avaliar modelos de plasticidade incremental. Este sistema eletromecânico utiliza como atuadores principais dois motores de corrente contínua conectados a caixas de redução para gerar os carregamentos de tração axial e/ou torção. O projeto da MTT compreende a análise de sua integridade estrutural, seu dimensionamento, e o cálculo da vida à fadiga de seus principais componentes; o projeto e desenvolvimento de uma célula tração-torção (LTC - load torque cell); o desenvolvimento e implementação das técnicas de controle; e finalmente sua construção e avaliação. Uma técnica de controle PID por modos deslizantes (PID Sliding Mode control) foi especialmente desenvolvida para esta máquina, consistindo em aplicar um sinal de controle descontínuo que força o sistema a deslizar ao longo de uma superfície de convergência. Esta técnica de controle tem a capacidade de controlar continuamente a força axial e/ou o torque aplicado ao corpo de prova de maneira independente, o que permite gerar histórias de cargas não-proporcionais. Os métodos de controle são implementados em uma plataforma computacional em tempo real CompactRio. Deste modo, é possível gerar uma máquina de ensaios de fadiga multiaxial compacta, de fácil manuseio, que não precise de um sistema de controle complexo, e a um baixo custo. A máquina tração-torção foi projetada para atender a uma ampla gama de ensaios de fadiga multiaxial, com uma capacidade de força axial máxima de mais ou menos 200 kN e torque máximo de mais ou menos 1300 N.m. O desempenho da MTT foi avaliado experimentalmente através de ensaios de plasticidade incremental. Para tanto, foram usados corpos de prova de tração-torção para medir seus comportamentos sobre cargas multiaxiais. Ensaios de encruamento não-proporcional, ratcheting (fluência cíclica) multiaxial e ratcheting uniaxial foram realizados em corpos de prova de aço inox 316, aço 1020, alumínio 7075 e alumínio 6063 na MTT, assim como em uma máquina Instron de 100 kN. Um simulador de plasticidade incremental para carregamentos de tração-torção foi desenvolvido, incorporando o modelo de encruamento cinemático não-linear de Jiang-Sehitoglu, e o modelo incremental de encruamento não-proporcional de Tanaka. Os parâmetros do material foram calibrados a partir de ensaios experimentais, permitindo que as simulações fossem capazes de prever o comportamento do material sobre diferentes histórias de carregamento, assim como as taxas de encruamento não-proporcional e de ratcheting. Os experimentos e simulações confirmaram tanto a adequabilidade da MTT desenvolvida, quanto do simulador de plasticidade incremental implementado, baseado nos modelos não-lineares de Jiang-Sehitoglu e Tanaka. / [en] The experimental evaluation of incremental plasticity models and fatigue life prediction under combined loads requires the use of multiaxial testing machines. In this work, an axial-torsion machine (MTT) was developed to evaluate incremental plasticity models. This electromechanical system uses as a main actuators two DC motors connected to gearboxes to generate the axial and/or torsion loads. The design of axial-torsion machine comprises the analysis of its structural integrity, its dimensioning and fatigue life prediction its major components; the design and development of a load torque cell – LTC; the development and implementation of control techniques, and finally, its construction and its performance evaluation. A PID Sliding Model control technique has been specially developed for this machine, which consists in applying a discontinuous control signal that forces the system to slide along a surface convergence. This control technique has the ability to control the axial force and/or torsion applied to specimen test in an independent manner, which allows to generate a non-proportional loading histories. The control methods are implemented on a computing platform in real time CompactRio. Thus, it s possible to developed a compact multiaxial fatigue testing machine, easy to handle, which does not require a complex control system, and at a low cost. The tensiontorsion machine was designed to meet a wide range of multiaxial fatigue tests, with a maximum capacity of axial force of more or less 200 kN and torque of more or less 1300 N.m. The MTT performance was evaluated experimentally by incremental plasticity testing. For this purpose, tensile / torsion specimens were used to measure their behavior under multiaxial loads. Testing of non-proportional hardening, multiaxial ratcheting and uniaxial ratcheting (cyclic creep) were performed on specimens of 316 stainless steel, 1020 steel, 7075 aluminum and 6351T6 aluminum in the MTT, as well as a Instron Machine of more or less 100 kN. A simulator of incremental plasticity to tensile-torsion loads has been developed, incorporating the non-linear kinematic hardening model of Jiang-Sehitoglu, and non-proportional hardening model of Tanaka. The material parameters were calibrated using experimental tests, allowing the simulations to predict the material behavior under different load histories, as well as rates of non-proportional hardening and ratcheting. The experiments and simulations confirmed both the suitability of the developed MTT, as well as the simulator of incremental plasticity implemented, based on non-linear models of Jiang-Sehitoglu and Tanaka.