Patent ID: 7843100
Filing Date: 2010-11-30
Classification: H02K,Y02T

Abstract:
1. An interior permanent magnet machine comprising: a wound stator; a rotor configured to magnetically interact with the wound stator; a plurality of cavities provided within the rotor; a plurality of magnets provided within the plurality of cavities, wherein the plurality of magnets includes a set of ferrite magnets and a set of associated rare earth magnets configured to prevent demagnetization of the ferrite magnets, wherein the distance between the set of rare earth magnets and a center of rotation of the rotor is less than the distance between the set of ferrite magnets and the center of rotation; wherein the total volume of each cavity is only partially filled by the plurality of magnets, such air gaps or non-magnetic regions are formed on each side of the ferrite magnets and on each side of the rare earth magnets; and wherein each ferrite magnet is paired with, and positioned symmetrically with respect to, a selected one of the rare earth magnets.