  Direct Torque Control (DTC) is well known as an effective control technique
for high performance drives in a wide variety of industrial applications and
conventional DTC technique uses two constant reference value: torque and stator
flux. In this paper, a new fuzzy based stator flux optimizer has been proposed
for DTC controlled induction motor drivers and simulation studies have been
carried out with Matlab/Simulink to compare the proposed system behaviours at
vary load conditions. The most important feature of the proposed fuzzy logic
based stator flux optimizer that it self-regulates the stator flux reference
value using the motor load situation without need of any motor parameters.
Simulation results show that the performance of the proposed DTC technique has
been improved and especially at low-load conditions torque ripples are greatly
reduced with respect to the conventional DTC.
