Improvement of DTC performance using luenberger observer for flux estimation

Abstract

Direct torque control (DTC) is one of the best performing strategies for induction motor control in many applications. However, this method suffers from a few disadvantages. Very important one is the presence of ripples in the torque waveform. The main reason of their presence is the inaccurate model of the motor. This paper utilizes Luenberger observer to calculate the model of the motor instead of the classical one. The DTC strategies with its original model and with Luenberger observer are created on dSPACE ds1103 platform. The results from experiment on a specific induction motor drive are shown. The paper shows better performance of the DTC with model based on Luenberger observer. The ripples in torque waveforms were lowered while switching frequency of the transistors remained the same.