Permanent magnet brushless machine with magnetic flux regulation

摘要

A permanent magnet machine (PMM) (2) comprises: a generally cylindrical permanent magnet (PM) rotor (4) that comprises multiple PM rotor poles (12) arranged around a rotor axis of rotation (6); and a stator with two generally cylindrical and concentric yokes (16,18), an inner yoke (16) proximate the PM rotor with associated multiple inner poles (20) and inner armafure windings (22) suitable for multiphase alternating current operation that form a PMM magnetic flux circuit, an outer yoke (18) with associated multiple outer poles (24) and outer control windings (26) suitable for connection to a direct current source, with distal ends (28) of the outer poles in contact with the inner yoke to form an external magnetic flux circuit that diverts magnetic flux from the PMM magnetic flux circuit; wherein application of increasing direct current to the outer windings results in increased magnetic reluctance of the external magnetic flux circuit, thereby causing the external magnetic flux circuit to divert less magnetic flux from the PMM magnetic flux circuit.