Decoupling control and parameter identification of field-oriented induction motor with saturation

A new decoupling control and self-commissioning parameter identification scheme for the PWM-inverter-fed asynchronous motor with saturation is presented. The modification of the field-oriented control model is considered with respect to rotor-flux-oriented control, while the nonlinear magnetizing curve is expressed as a function of the magnetizing current of the main flux path. The control model and the magnetizing curve are bridged through the inherent relationship between the rotor flux and the airgap flux. The complex signal flow graphs indicate that the dynamic structure of AC machines are not changed with magnetic saturation effects. The nonlinear magnetizing curve is estimated from a transient voltage caused by an ejected constant stator d-axis current. Experiment results indicate that the vector control of induction motor with saturation can be finely realized with the proposed model, on the basis of the recognized magnetizing characteristics.