In this paper, we present the application of the control of doubly fed induction machine, using direct torque control (DTC). This method has a simple and robust control structure; the performance of DTC strongly depends on the quality of the estimated actual stator flux and torque. DTC with switching tables provide excellent torque dynamics. The implementation of the DTC applied to a double feed induction motor is validated with simulated results. The results demonstrate that the proposed controller leads to performance improvements despite its simple structure.
Dans le domaine des applications à basse vitesse, l’intérêt se porte actuellement sur l'utilisation de machines électriques directement connectées à la charge. Ceci dans l'objectif de réduire les pannes mécaniques en supprimant le multiplicateur de vitesse. La présente communication consiste à dimensionner et à étudier deux exemples de structures Vernier excitées. Dans un premier temps, nous proposons le dimensionnement, en utilisant des approches classiques, de deux machines à réluctance variable excitée soit par des aimants permanents ou encore par un circuit triphasé statorique. Dans une seconde étape, nous utilisons une approche numérique basée sur le calcul de champs magnétiques par la méthode des éléments finis pour étudier le fonctionnement des deux prototypes. Enfin, nous comparerons les performances des deux structures en fonctionnement moteur autopiloté.
This paper proposes a new sensorless control method for the speed and position control of a BLDC Motor. This sensorless drive technique calculates the commutations instants (duration of commutation) by deriving the sum of the terminal voltages of the motor (SigVi). Thus, it is possible to estimate the rotor position (and back EMF of the motor) by only using measurements of the stator line currents and voltages. The implantation of these detectors is easy and cheap. This method is quite robust across variations in stator resistance due to changes in temperature or frequency. With this method the motor can be started without needing the initial position of the rotor. This proposed method is validated through extensive simulations at different speeds, and a very satisfactory performance has been achieved.
Direct torque control (DTC) is known to produce fast response and robust control in AC adjustable-speed drives. However, in the steady-state operation, notable torque, flux, and current pulsations occur. In this paper a nonlinear DTC of IM drives is presented based on a Space Vector PWM scheme combined with Input–Output Feedback Linearization (IOFL) technique. The variation of stator and rotor resistance due to changes in temperature or frequency deteriorates the performance of DTC controller by introducing errors in the estimated flux linkage and the electromagnetic torque. As a result, this approach will not be suitable for high power drives such as those used in tractions, as they require good torque control performance at considerably lower frequency. Finally, extensive simulation results are presented to validate the proposed technique. The system is tested at different speeds and a very satisfactory performance has been achieved.
