Speed sensorless direct torque control and stator resistance estimator of induction motor based MRAS method

The stator resistance variation will deteriorate the performance of a direct torque controlled (DTC) system, and therefore is a big issue of DTC. To solve this problem, we present the structure for a model reference adaptive system (MRAS) for direct torque control (DTC) in induction motor, which estimates speed based on the governing equations of the induction motor and compensate machine parameters. Depending on requisition or working condition of the drives, each machine parameter has been monitored and compensated case by case. Stator resistance, Rs, has been compensated in this paper. Simulation results shows validate the effectiveness of the proposed method.