Research on a modified ELF for speed estimation in induction motor drives

This paper presents and proposes a new approach to resolve the problems of large operation algorithm, very short sample time and redundant parameters tuning in induction motor sensorless vector control. The estimation method is based on a long sample time, reduced-order EKF. With this model structure, only the rotor flux components are estimated, besides the rotor speed itself. The new methods predict the rotor speed in the every sample time. So it does not need a short sample time to assume that the differential of speed to be zero. Simulation results show that this new approach can enable us to reduce the execution time of the algorithm without difficulties related to the tuning of covariance matrices and achieve robust speed estimation even in the condition of long sample time.