Two-degree-of-freedom speed control of induction motor having two-mass resonant system

This paper examines the speed control of an induction motor system which has a motor and a load connected via a flexible shaft. Such a system often generates shaft torsional vibrations. These vibrations makes it difficult to achieve a fast response to the speed command and may result in damage to the plant. In this paper, a speed control scheme based on two degree-of-freedom control is proposed. The feedback part is designed to suppress torsional vibrations and reject torque disturbances. The feedforward part is also designed to improve the speed response to commands.