Analysis of the Dual-Excited Synchronous Machine

This paper presents a generalized analysis for the dual-excited synchronous machine, in which, on the contrary of previous work, the two field windings are not necessary located on the rotor axes, and may not have the same number of turns or the same inclination angle to the physical axis of the pole structure. In deriving the general equation of the machine, no approximations are introduced other than those required for deriving Park's transformation, and so the analysis provides a more exact representation for this machine. Also a new per-unit system is applied, as the conventional one would introduce errors if the saliency is to be taken into consideration. The external connection is considered in a general form so as to allow for studying the machine performance when it is connected to an infinite-bus through a general transmission system. The small displacement model is derived and arranged in a form suitable for investigating dynamic stability problems. The model provides a good tool for studying the effect of using numerous schemes of excitation regulation on the dynamic behaviour of the machine.