Stability improvement of round rotor synchronous machine by using a two-way parallel field winding

The stability improvement of a round rotor synchronous machine by using a two-way paralleleeld winding is examined. The characteristic machine parameters are derived varying the electrical angle between the two magnetic axes of the eeld windings. By using a simplieed mathematical model, a comparison between a conventional synchronous machine and the new machine with a modieed eeld winding is performed in order to evaluate the stability bounds. The new machine shows an improved dynamic performance in the presence of large perturbations. The stability bounds increase if the electrical angle between the two magnetic axes of the eeld windings grow up to an optimal value of about 60 degrees (for constructional constraints, 60 degrees is the maximum angle between the two magnetic axes of the eeld windings).