Sensorless speed estimation of induction motor based on the secondary and primary resistance on-line identification without any additional signal injection

In the low speed region, it is difficult to estimate the rotor speed of the induction motor, because the machine parameter (especially R₂) has a strong influence to the speed estimation. It is known that the simultaneous estimation of the speed and R₂ is impossible. In this paper the R₂ estimation in the transient state without adding any additional signal to the stator current is proposed, and the R₁ is estimated from the instantaneous reactive power. These algorithms are verified by the digital simulations and the experiments.