FIELD-ORIENTED CONTROL OF AN INDUCTION-MOTOR WITH ROBUST ONLINE TUNING OF ITS PARAMETERS

This paper proposes new torque control of an induction motor, which is robust against primary resistance and adaptable to leakage inductance , magnetizing inductance, and secondary time constant, The control is based on flux feedback with a Bur simulator, Since the simulator is ba sed on a rotor current model, it is independent of the primary resista nce, but uses the magnetizing inductance and secondary time constant v alues to estimate the flux, Parameter mismatch in the simulator detrim entally affects flux and torque responses, In order to compensate for degradation of the responses, an identifier for the magnetizing induct ance and the secondary time constant is introduced, The identifier is insensitive to the primary resistance because it is based on instantan eous reactive power of the motor, Also, a leakage inductance identifie r is introduced to achieve perfect compensation, which is robust again st other parameters owing to instantaneous harmonic reactive power, To verify feasibility of the proposed technique, digital simulations and experimental tests have been conducted, The results have proven excel lent characteristics of the drive system, which confirms validity of t he scheme.