MRAS Speed Observer for Direct Torque Control of Sensorless Induction Motor Drives Sensitivity Study

摘要

To avoid the use of mechanical speed sensor in Direct Torque Control of induction motors, it was agreed to estimate by an estimator using electrical measurements and machine parameters. This study presents a speed sensorless drive of induction motors. The proposed speed estimator is based on the Model Reference Adaptive Scheme (MRAS) and uses based the comparison of estimated and measured stator current. The reduction error is achieved by an appropriate unity transfer function as reference model. The estimator formulation is defined and developed in the discrete case. The proposed algorithm requires neither matrix calculation nor approximation on Taylor series of matrix exponential. The effect of variation parameters on the estimated speed is presented. Some simulation results are shown, in order to valid the theoretical development.