Direct torque control of induction machines with current limitation and ripple reduction using fuzzy logic

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 1 ？ hp induction motor and the plataforma iii system developed by the siep group of the simón bolívar university.