Abstract:
With the advancement of power electronics and digital technologies command, several control structures for the AC machines were proposed, in order get performance identical to those of the DC machine. Field oriented control (FOC) has been in recent years towards research largest and best suited to industrial requirements. However, this structure remains very sensitive to parameters variations of the machine and requires the establishment of a mechanical sensor. The present study deals with development of a control strategy for induction machines, Able of provide a high dynamic response of electromagnetic torque with robustness against parametric variations No sensor. A direct torque control strategy makes it possible to achieve these goals. Indeed by choosing the right inverter output vectors in a switching table, the stator flux and electromagnetic torque are controlled directly and independently. However, some disadvantages are also present such as, switching frequency is not controlled, the ripple in the torque and stator flux and effect of stator resistance variation in low and medium speed. The main goal of this thesis to introduce different strategies for Improvement of performance of the (DTC). Numerical simulations in Matlab/Simulink Have been implanted for validate the proposed method.
