Current control for induction motor drives based on input-output dynamic discrete model

A current control strategy for an asynchronous machine was formulated, studied, and simulated. In the design of the controller a time-varying multiple-input multiple-output model is used to describe the relationship between stator current and the voltage. However, in the discrete equivalent MIMO model the dominant parameters have a restricted variation range due to the discretization. On the other hand, since this model depends only on the terminal quantities, its parameters can be easily estimated. The current control was implemented using the predictive technique. The parameters of the controller were obtained using the recursive least squares estimation technique. The performance of the system was evaluated using the transfer matrix approach. The plotting of the Bode curves and the computation of the zeros and poles of the model were used to predict the closed-loop static and dynamic behavior. The time response results agreed with those predicted using the frequency response technique