Abstract
variable magnetomotive force memory motor (VMFM) is a motor that can expand its operating range by changing the magnetization state of a variable permanent magnet. However, changing the magnetization state requires a pulse current several times larger than the armature current rating. This paper proposes a method using magnetization coils in the stator to reduce the magnetization current in each power semiconductor device for VMFM. The proposed VMFM is equipped with magnetization windings in addition to the three-phase drive windings on the stator teeth, and the magnetization windings are connected in parallel with the drive windings and powered by the same inverter. By turning ON all three upper or lower arms simultaneously, the magnetization current per device can be limited to one-third of the inverter rating. Magnetic field analysis confirmed that the proposed VMFM satisfies target load points that the base PMSM cannot reach, demonstrating that a small device and low cost can be achieved while maintaining manufacturability.
