A new speed estimation scheme of the induction motor considering the flux saturation

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