A Novel Control Scheme to Mitigate Unbalanced Magnetic Pull due to Eccentric Rotor in Three Phase Induction Motors

Abstract

Rotating machines with low air gap are always prone to Unbalanced Magnetic Pull (UMP) due to eccentric rotors. As a consequence, rotor-stator rub contact occur leading to complete outage of the machine. This paper proposes a control scheme to reduce the effects of eccentricity in 3 phase induction motor by introducing Feedforward (FF) and Feedback (FB) control. Active Magnetic Bearings (AMB) are incorporated to implement this scheme. To analyse the UMP for statically eccentric rotor and also for conical rotor motion in a 3 phase induction motor, Finite Element (FE) method is utilised. These values are used to design the proposed controller.