Induction Machine Torque Control with Self-Tuning Capabilities

Abstract

In any torque control concept for induction machines the capability to produce a desired torque with the minimum stator current (maximum torque per ampere ratio) becomes a demanding requirement. In this contribution it is shown how a recently published torque control strategy which provides the maximum torque per ampere ratio feature can be augmented by some self-tuning capabilities. Since the behaviour of the proposed controller is mainly influenced by the rotor time constant which is subjected to variations due to thermal influences on the rotor resistance a method for an on-line tuning of this parameter is developed. It is based on the extremum seeking approach, which is well known from adaptive control. The performance of the control concept is demonstrated by experimental results.