Patent ID: 8044546

Claim:
A permanent magnet electric machine comprising: a rotor, a stator surrounding the rotor with an air gap between an outer periphery of the rotor and an inner periphery of the stator; electrical windings in the stator; multiple magnets in the rotor in close proximity to the stator windings; and openings in the rotor, the openings being located adjacent separate pairs of magnets and between the separate pairs of magnets and the air gap; one magnet adjacent each pair of magnets being located closer to an opening in the rotor than the other magnet of that pair thereby establishing an asymmetric rotor structure; the magnets having an electromagnetic flux pattern for the magnets that interacts with an electromagnetic flux pattern for the stator windings to define an asymmetric flux flow path around the openings that envelop the pairs of magnets whereby the machine operates with a higher efficiency in a motoring mode and a reduced efficiency in a generating mode.