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A smooth fault-tolerant control (FTC) of induction motor drives with sensor failures is presented in this paper. The drive uses concurrently active direct torque control (DTC), indirect field-oriented control (IFOC), and volts-per-hertz (V/f) controllers as replacements of each other in the case of sensor failure or recovery. Speed encoder, current, and voltage sensors are considered. The DTC and IFOC controllers are properly modified and integrated with the V/f controller in synchronous frame, which allows switching between dc-type voltage commands of different controllers. Therefore, difficult synchronization of different controllers is avoided, and a simple rate limiter is able to achieve smooth handoff transition of different controllers. Details of the DTC, IFOC, and V/f controllers, as well as their integration are presented. Simulation and experimental verification of the proposed FTC are given, where normal abc-frame switching and the proposed synchronous-frame switching of controllers are compared with different switching schemes and at different machine operation conditions. Simulation and experimental results show significantly smoother handoff transients. [ABSTRACT FROM AUTHOR]

An analytical three-phase induction machine model is proposed, derived, and validated in this paper. This model is capable for arbitrary qd0-frame analysis and core loss estimation at both line-fed and inverter-fed situations. Detailed model-based machine copper and core loss estimations are presented. A simulation verification of the model consistency is given under a changing load profile in MATLAB/Simulink. Then, the model is verified comprehensively using three induction machines (1.5 HP, 3 HP, and 10 HP), where the model is proved to be scalable, and to provide excellent machine loss estimation in line-fed situation and inverter-fed situation with machine input line filters, as well as in the flux-weakening region. Finally, a series of sensitivity tests of the model parameters are performed and the effects of the parameters on the machine losses are discussed. It is believed that the proposed model will be beneficial for various qd0-frame model-based research works of three-phase induction machines. [ABSTRACT FROM AUTHOR]

This paper reviews and compares available techniques for minimizing power loss of induction motors. It identifies a separate category of loss minimization techniques (LMTs)—hybrid LMTs. Techniques have different convergence rates, parameter dependence, and convergence errors. Offline techniques are introduced and real-time techniques are detailed. Real-time LMTs are divided into model-based, physics-based, and hybrid categories. Application of a real-time LMT to a hybrid electric vehicle (HEV) is examined. Simulation and experimental results verify the characteristics of each category of real-time LMTs. Sensitivity of real-time LMTs to motor parameters is discussed. It is shown that techniques can be chosen based on application-specific requirements and that hybrid LMTs balance partial parameter independence and fast convergence to achieve the best overall performance. [ABSTRACT FROM PUBLISHER]