Model reference adaptive speed control for doubly-fed machines

A brushless doubly-fed motor drive attempts to realize the benefits of adjustable speed drives while reducing size and rating of the associated power converter. Since only one of the two sets of stator windings is controllable, conventional methods of field orientation are not directly applicable. This has led to the development of a predictive algorithm based on the principle of self control. The paper discusses enhancement of the dynamic response of the doubly-fed drive under direct torque control by providing for a model reference adaptive controller in the speed loop; the direct torque control algorithm is shown to be quite robust with respect to system electrical parameters. Simulation results illustrate the improved performance over conventional PI-regulators