Performance of a Doubly-Fed Induction Motor with Controlled Rotor Voltage Magnitude and Phase Angle

The performace of a doubly-fed induction motor (DFM) controlled by a voltage phasor at the rotor side is investigated. This voltage has two control parameters: the magnitude and the phase angle. By controlling each one of these two parameters, it is possible to produce the appropriate voltage phasor which must be applied to the induction motor slip rings for achieving certain operation, i.e. any function of load power versus speed. The electromagnetic characteristics in the steady state are determined when the voltage magnitude and its phase angle varies from zero to their upper limits. These limits are dictated by improving performance considerations.