Sub-Harmonic Synchronous Machine Using a Dual Inverter and a Unique Three-Layer Stator Winding

A dual inverter sub-harmonic synchronous machine having a distinct three-layer stator winding topology is presented. The two inverters provide two sets of balanced three-phase currents to the three-layer stator winding. These three-layer windings are arranged in such a way that they can generate both fundamental and sub-harmonic magnetomotive force. Furthermore, the fundamental MMF component of this machine is four times the sub-harmonic MMF component used for the brushless operation. In contrast, the subharmonic magnetomotive force is used for field excitation, which leads to brushless operation. An 8-pole 48-slot 2-inverter 3-layer subharmonic machine is designed to validate the concept through a 2-D finite element analysis of this new topology, showing a better overall torque profile and performance.