Abstract: An electrical machine is provided. The machine includes at least one rotor mounted for rotation about a central axis and at least two stator sections mounted axially adjacent to and on opposite sides of the rotor. The rotor includes two circumferentially arrayed rows of alternating segments of permanent magnet and ferromagnetic pole pieces. One of the rows is spaced radially inwardly from the other row. The permanent magnet and ferromagnetic pole pieces are separated by a non-ferromagnetic material. The pole pieces are arranged so that the permanent magnet segments in the first row are radially adjacent to ferromagnetic segments in the second row so that the N-S magnetic fields of the permanent magnet segments are aligned axially. Each stator section includes a ferromagnetic stator frame, at least a first AC winding wound in circumferential slots in the stator frame, and a DC field winding wound on the stator frame.

Abstract: An electrical machine is provided. The machine includes at least one rotor mounted for rotation about a central axis and at least two stator sections mounted axially adjacent to and on opposite sides of the rotor. The rotor includes two circumferentially arrayed rows of alternating segments of permanent magnet and ferromagnetic pole pieces. One of the rows is spaced radially inwardly from the other row. The permanent magnet and ferromagnetic pole pieces are separated by a non-ferromagnetic material. The pole pieces are arranged so that the permanent magnet segments in the first row are radially adjacent to ferromagnetic segments in the second row so that the N-S magnetic fields of the permanent magnet segments are aligned axially. Each stator section includes a ferromagnetic stator frame, at least a first AC winding wound in circumferential slots in the stator frame, and a DC field winding wound on the stator frame.