Compensation of main flux saturation effects in UFO controller operating in the airgap flux reference frame

A modified, adaptive decoupling circuit for the universal field oriented (UFO) controller which operates with orientation along airgap flux is presented. The proposed circuit is capable of instantaneous adaptation to the actual magnetizing flux saturation level in the machine and is only slightly more complicated than the standard constant parameter one. The adaptive circuit is verified by simulating the dynamics of an indirect airgap flux oriented induction machine. Possible simplifications of the full adaptive decoupling circuit are addressed and assessed by simulation. Corresponding adaptive decoupling circuits for rotor oriented control and stator flux oriented control are given and possibilities of unifying the saturation treatment in generalized decoupling circuit of the UFO controller for an induction motor drive are discussed