Field-weakening control for an IFO induction motor drive

The transient performance improvement for an indirect field-oriented (IFO) induction motor drive with field-weakening is studied in this paper. In the proposed method, the saturation effect of magnetizing inductance is considered by representing it using a fitted quadratic polynomial of flux current. The flux current command is composed of three parts, namely the no-load, the loading compensated and the transient compensated components. The first one is represented by a third-order polynomial of rotor speed, which is estimated at no-load to consider the effects of nonlinear magnetizing inductance and the limitation of motor rated voltage. As for the latter two components, they are utilized to further weaken the field such that current tracking performances during loaded cases and transient period can be improved.