Exact tracking by dynamic field-weakened PMAC servodrive

Abstract

In the paper the exact tracking of permanent magnet AC servodrives with dynamic field-weakening is presented. The analytical solution given in the form of a reference dynamic model of the direct axis current and corresponding transition conditions is derived from the inverse motor dynamics. The presented solution guarantees the control voltage to remain within the constraint during steady states and transients, and also preserves exact tracking of the prescribed mechanical trajectories in the field weakening mode. The suggested method is independent of the implemented control structure. Analytical results have been confirmed by the experiments.