Fuzzy logic direct torque control

Abstract

A brief review of the different induction motor drives is done and its reason of being such a high matter of interest is summarised. Next, the direct torque control (DTC) in induction motors with its fundamental principles and schemes is described. Once the DTC is described, its main drawbacks are introduced. One of the goals of the paper is to overcome one of the worst disadvantages of the DTC, which is the existence of a considerable ripple in its torque response. The previously explained DTC limitations involve plenty of nonlinear functions. Therefore, artificial intelligence is suggested to overcome the DTC limitations. Hence, a fuzzy logic DTC controller, which is based on the classical DTC but includes a fuzzy logic controller, is described. Finally an optimised method of calculating the stator reference flux value is presented, which can be applied in any kind of induction motor drive. This optimised stator flux reference value not only improves the torque ripple, but also reduces the power consumption from the mains. Simulated results are shown to corroborate all the presented work and the updated workbench where all the experimentation is realised is also described.