Abstract—If the air-gap flux of the induction motor is saturated,
the conventional adaptive speed estimator cannot avoid
the influence of the nonlinear inductance variation. This paper
presents a new speed estimation scheme that estimates the rotor
speed and the mutual inductance simultaneously. The proposed
estimator consists of an error between the flux derived from the
stator voltage equation and the flux estimated from the rotor flux
observer. Introducing a new error correction term into the speed
estimator increases the estimation ability of the conventional speed
estimator although the motor flux is saturated. The experimental
results show the validity of the proposed method.