公开(公告)号：US10770958B2

公开(公告)日：2020-09-08

申请号：US16169117

申请日：2018-10-24

Applicant: ROLLS-ROYCE plc

Inventor： Ellis F H Chong ,  Shanmukha Ramakrishna ,  King Jet Tseng ,  Kin Hey Chu

IPC: H02K21/04 ,  H02K23/22 ,  H02K9/10 ,  H02K1/22 ,  H02K9/16 ,  H02K1/16 ,  H02K1/27 ,  H02K3/16

Abstract: A synchronous electrical machine includes a stator having a circumferential row of teeth carrying stator windings. The electrical machine further includes a coaxial rotor having a circumferential row of poles carrying field windings. Each pole has first and second side flanks and a tip surface which extends continuously there between to form an air gap to the teeth of the stator. On a transverse cross-section through the machine, one of the side flanks forms a leading edge of the pole, and the other side flank forms an opposite, trailing edge of the pole. Each pole carries a row of permanent magnets which extends across the tip surface from one of the side flanks to the other side flank, the permanent magnets compensating for armature magnetic reaction. The radial thickness of the permanent magnets increases smoothly with progressive distance across the tip surface from one of the side flanks to the other side flank.