Development of a low-speed multi-pole synchronous machine with a field winding on the stator side

This paper proposes a new type of multi-pole synchronous machine in which 2p_a-pole armature and 2p_f-pole field windings are centrally wound around individual stator teeth. The proposed machine operates as a (2p_a+2p_f)-pole synchronous machine by providing a magnetic coupling between the armature and field windings through a 2p_r-pole reluctance rotor. A 4-kVA, (32+48)-pole prototype machine was designed and built to validate the principle of this structure. Basic characteristics of the prototype machine were simulated using finite element analysis (FEA) and were supported by experiments.