A permanent magnet AC machine

摘要

A permanent magnet AC generator (10) that includes two disc-shaped rotors (20), each with permanent magnets (22) mounted thereon, and an annular stator core (14) sandwiched between the two rotors (20) and positioned coaxially therewith. A stator winding (16) is wound around the annular stator core (14) such that ends of the stator winding 16 serve as output terminals (18) for the generator (10). In operation, the magnets (22) set up an excitation field such that rotation of the two rotors (20) relative to the stator core (14) and the winding (16) results in an emf being induced in the winding (16). If current is drawn from the winding (16) by an electrical load connected across the terminal (18) thereof, such a current sets up a reaction field around the winding (16) that interacts with the excitation field and tends to alter the magnitude of the induced emf. The generator (10) also includes a control winding (30) wound around the annular stator core (14). Current flow in the winding (30) sets up a control field that tends to oppose the reaction field so as to reduce the effects thereof.