Model based speed and rotor resistance estimation for sensorless vector-controlled induction motor drives using floating point DSP

The paper deals with the aspects related to simultaneous rotor speed estimation and rotor resistance identification in field-oriented induction motor systems using only the induction motor model. A statistical based computing algorithm is proposed in order to avoid the division by zero. Three basic algorithms have been considered in order to establish the optimum solution. The study of the speed and rotor resistance estimator has been performed together with a Gopinath flux observer. Hence, the rotor flux, rotor speed and resistance have been estimated using only the electrical feedback magnitudes of the motor: the stator voltages and currents. The estimated rotor resistance is applied to the input of the flux observer and voltage compensator blocks. The simulation results prove the simplicity and the performance of the estimator based only on the electromagnetic phenomena inside the motor.