Direct Torque Control of Induction Machines with Current limitation and Ripple Reduction Using Fuzzy Logic

Abstract

The classic Direct Torque Control scheme proposed by Takahashi y Noguchi [1] obtains fast torque responses of the induction machine. This control scheme however does not regulate the current demand, and the developed torque presents high ripple levels. In this paper a modification to the DTC algorithm is presented where a control loop is added to limit the stator current to a preset value. The proposed control strategy also allows for stator voltage regulation, resulting in a reduction of the electric torque ripple. In the proposed scheme the control voltage vector amplitude modulation is accomplished by a fuzzy controller with two inputs. The proposed control scheme was analized in simulations performed in C language, and afterwards experimental results were obtained with an 1½HP induction motor and the Plataforma III system developed by the SIEP group of the Simón Bolívar University.  Â