Design and Analysis of a Novel Brushless Wound Rotor Synchronous Machine

This paper presents a new concept for brushless excitation of a wound rotor synchronous machine (WRSM) based on the generation and utilization of a subharmonic component of the stator magnetomotive force (MMF). In this method, a dual inverter topology for the stator winding is proposed. The idea is to generate and utilize an additional subharmonic stator MMF component along with the fundamental component. The rotor carries two different windings: 1) excitation winding and 2) field winding. The subharmonic component induces voltage in the excitation winding and feeds the field winding through a rotating rectifier on the rotor. A 2-D finite-element analysis was performed to analyze and verify the proposed brushless WRSM