Time optimal control for induction motor servo system

A time-optimal position control scheme based on Pontryagin´s minimum principle is proposed for a current-source-inverter (CSI) fed induction motor system. The induction motor with field-oriented control is modeled with a fast time-optimal position control system of second order which has two modes of operation: the first bang-bang mode operates until the position is close to target, followed by second DC braking mode which gives asymptotic stability. In order to realize this aim, the time-optimal controller is added instead of the speed controller to the conventional field oriented control loop of the CSI-fed induction motor. The validity of the time-optimal control solution has been verified by an experimental test. Experimental results are in close agreement with a digital simulation