Sensorless speed estimation based on primary and secondary resistance estimation and output voltage compensation of induction motor

Abstract

In the very low speed region, it is difficult to estimate the rotor speed of the induction motor, because the machine parameter (especially R/sub 2/) has strong influence on the speed estimation. It is known that the simultaneous estimation of the speed and R/sub 2/ is impossible. In this paper R/sub 2/ estimation is proposed in the transient state without adding any additional signal to the stator current, and the output voltage compensation without the voltage sensors. R/sub 1/ is estimated from the instantaneous reactive power.