On the Speed Control of Wound-Rotor Induction Motors Using Rotor Impedance Control

Significant improvements in the performance of rotor impedance control for constant speed operation of wound-rotor induction motors can be achieved by the introduction of an inductor as a third element of the series resistor-capacitor combination in the rotor circuit. These improvements include better speed regulation and a reduction in physical size of capacitor throughout the speed control range. However, for higher speed ranges the addition of a parallel R-L section is found necessary for further improvement in performance.