Abstract: Due to the strong coupling between rotor speed and rotor time constant in the indirect vector control

system of induction motor，it is difficult to realize their parallel identification. The parallel identification based on

multi-innovation extended Kalman filter based on forgetting factor（FMI-EKF）was proposed to reduce the error

bandwidth of the Kalman filter parallel identification system and improve its reliability. Meanwhile in order to avoid

data saturation，a forgetting factor was introduced to reduce the dependence of the system on historical data. The

simulation results show that the proposed parallel identification of speed and rotor time constant is suitable in the

range of full speed and full rotor time constant，which has enhanced capability against disturbances. And compared with the traditional Kalman filter system，the accuracy of the parallel identification is significantly improve by the proposed FMI-EKF.

      Key words: induction motor；speed sensorless；rotor time constant；multi-innovation；Kalman filter