Patent ID: 9130422
Filing Date: 2015-09-08
Classification: H02K

Abstract:
1. An interior permanent magnet machine comprising: a wound stator; a rotor core including at least one ferrite pole defining a plurality of first pole cavities, and at least one rare earth pole defining a plurality of second pole cavities, wherein the rotor core magnetically interacts with the wound stator for rotation about a central axis of rotation; a plurality of ferrite magnets, with one of the plurality of ferrite magnets disposed within each of the first pole cavities of the at least one ferrite pole; and a plurality of rare earth magnets, with one of the plurality of rare earth magnets disposed within each of the second pole cavities of the at least one rare earth pole; wherein the plurality of ferrite magnets of the at least one ferrite pole are arranged in at least a first row, a second row, and a third row radially spaced from each other relative to the central axis of rotation, with the third row spaced nearer the central axis of rotation than the second row, and the second row spaced nearer the central axis of rotation than the first row; wherein all of the ferrite magnets in the first row have a first thickness, all of the ferrite magnets in the second row have a second thickness, and all of the ferrite magnets in the third row have a third thickness, with the first thickness being less than the second thickness, and the second thickness being less than the third thickness; wherein the plurality of rare earth magnets of the at least one rare earth pole are arranged in at least a first layer and a second layer, wherein a cross sectional shape perpendicular to the central axis of rotation of each of the first layer and the second layer defines a concave V-shape having an apex of the concave V-shape disposed on a second pole axis, and with the first layer disposed radially farther from the central axis of rotation than the second layer; wherein the rare earth magnets of the first layer include a first thickness and the rare earth magnets of the second layer include a second thickness, with the first thickness less than the second thickness; and wherein the rare earth magnets of the at least one rare earth pole are arranged about the second pole axis to define a first group of the rare earth magnets that are entirely disposed on a first side of the second pole axis, and a second group of the rare earth magnets that are entirely disposed on a second side of the second pole axis, such that all of the rare earth magnets of the at least one rare earth pole are disposed in either the first group or the second group of rare earth magnets, with none of the rare earth magnets extending across the second pole axis.