Limitations of the rotor voltage of doubly fed induction generator in shaping the slip-torque characteristics

The paper is concerned with the wind energy conversion system (WECS) applying doubly fed induction generator. It addresses the question whether the slip-torque characteristic of the generator belonging to short circuited rotor can be shifted along the slip axis only by the rotor voltage in the slip range ±0.3 resulting in more-less similar set of slip-torque characteristics as can be achieved with induction machine supplied by variable frequency. The study includes small, average and large induction generators applied in WECS.