Induction machine field orientation along airgap and stator flux

Airgap and stator flux field orientation control (FOC) methods are discussed as an alternative to the familiar rotor flux orientation approach. The principal motivation is the relative accessibility of the two alternative fluxes. Motor flux models are developed in a unified manner, and it is shown that inherent coupling between flux and torque exists in the stator and airgap models. Two decoupling methods are presented. Simulation results are given for an airgap oriented control; the performance approaches that of a rotor flux oriented drive