Simulation of Sensorless Speed Control of Induction Motor Using Direct Torque Control Technique Employing Five Level Torque Comparator and Twelve Sector Method

Our nuclear industry in general has employed induction motors in almost every electro-mechanical process. Speed and position control of these motors are envisaged at multiple occasions. For better dynamic response, vector control of speed is preferred over scalar methods namely V/F method, etc. Estimation of speed, stator flux, rotor flux and the torque developed by electromagnetic field is done using the value of the DC bus voltage, motor parameters and the stator current of any two phases of star connected induction motor. In this paper, the technique uses a two - level hysteresis comparator for stator flux, five - level hysteresis comparator for torque and divides the ‘dq’ plane in twelve sectors for determining the switching of Space Vectors from a Voltage Source Inverter. The model is simulated with a centrifugal pump load. The estimation methodology and simulation is discussed in this paper. Conclusions drawn have been highlighted using the simulation results and hardware implementation is proposed for validation of simulation results.