A voltage feeding algorithm for direct torque control of induction motor drives using state feedback

AC motor drives are experiencing and exciting new impact in industrial automation applications as well as in research studies. Inherent advantages of adjustable frequency operation cannot be fully exploited without adopting a suitable control strategy. The paper gives a fully digitalised direct torque control algorithm for induction motor drives using state feedback control of the motor. The goal of the control strategy consists in achieving a very fast response of the torque control loop and poor parametric sensitivity. The proposed feeding algorithm has been called “direct”, because it links directly armature feeding voltages to the reference value of the electromagnetic torque and to the reference value of the flux. In the paper, the suggested control strategy is presented and the dynamic performances of induction motor drive are analysed. The control technique seems to be a good compromise between accuracy and easy handling of the control algorithm. The results show the good dynamic performances of the system and the feasibility of a microprocessor implementation of the feeding algorithm on a high performance evaluation board, in order to realise real-time control