Power Quality Improvement In Sensorless Direct Torque Controlled Induction Motor Drive

A 12-pulse AC-DC conversion fed 3-level neutral point clamped (NPC) multilevel inverter (MLI) configuration is presented for power quality improvement for sensorless direct torque control (SLDTC) induction motor drive (IMD). At the grid side of proposed SLDTC, a 12-pulse AC-DC conversion and a high pass filter, is utilized to suppress the grid current harmonics to an acceptable level. A 3-level NPC is utilized to improve the performances at the motor end. A SLDTC is utilized to control an IMD, which has good transient response during any required operation of presented IMD. The speed and torque of IM, are estimated by utilizing stationary flux in alpha beta-frame. A five level torque hysteresis controller technique is proposed in this paper, which significantly reduces the torque ripple of proposed IMD. Extensive simulation results are demonstrated here to show the proper and desired performances of proposed SLDTC-IMD by utilizing MATLAB/Simulink platform.