Speed sensorless control performance improvement of induction motor drive using uncertainty cancellation

An improved speed estimator using parameter uncertainty cancellation and it s application to an indirect field-oriented induction motor drive are prese nted. First, the speed estimation errors of a V-I model-based adaptive spee d observer due to parameter variations are analysed. Then, accordingly, a n ovel compensation scheme is developed to cancel the effects of parameter va riations on the estimated speed performance; A variable structure system co ntroller, with the detected error signal as its input, is employed to reali se the proposed compensation scheme. Finally, the robust speed control with quantitative control performance considering the effect of dead-time enlar gement due to the feedback of estimated speed is presented. Theoretic bases of the proposed speed estimator and the robust speed controller are derive d in detail, and their validities are demonstrated by some simulation and m easured results.