Magnet arrangement in novel flux-modulating synchronous machines with permanent-magnet excitation

Fukami et al. previously proposed a novel type of multipole synchronous machine (SM) in which armature and field windings are centrally wound around individual stator teeth. Since the stator magnetomotive force (MMF) due to the field winding is modulated by the salient poles on the rotor to produce the main magnetic flux, this multipole SM is called the “flux-modulating SM (FMSM).” Although the FMSM looks like a switched reluctance machine, its characteristics are similar to those of conventional SMs. This paper investigates the magnet arrangement in FMSMs with an outer-rotor configuration in which the function of the field winding is replaced by permanent magnets (PMs). Hereafter, the outer-rotor FMSMs with the PM excitation will be referred to as the “PM-type FMSMs.”