Transputer-based adaptive speed controller for AC induction motor drives with load torque estimation

This paper presents the design and implementation of an adaptive speed controller with load torque estimation for ac induction motor drives using transputer-based parallel processing technique. This adaptive speed controller that precedes the field-oriented control loop consists of a two-degree-of-freedom controller and an estimator-based load-torque feedforward compensator. The controller is designed by using pole-placement technique with polynomial manipulations. Its parameters were adjusted adaptively in terms of estimated model parameters. The model estimation uses a second-order least-squares estimator with constant trace for the avoidance of estimator windup. The load torque estimation uses a first-order least-squares estimator with variable forgetting factor and covariance resetting to detect slow and sudden change of torque disturbance, respectively. The resulting adaptive controller is implemented in parallel using IMS T800-20 transputers. Experimental results show the robustness of the proposed control method against varying load and torque disturbance.