Patent ID: 7122923

Claim:
Power conversion apparatus comprising: a rotor comprising a cylindrical casing, and a predetermined number of permanent magnets disposed in the interior of the casing, the rotor being adapted for rotation about the axis of the casing over a predetermined operational range of rotational speeds; a stator comprising a core and at least one conductive winding, the core including a generally cylindrical outer peripheral surface and a predetermined number of slots formed therein; the winding being wound around the core through the slots and including end turns extending outwardly from the core, the stator being concentrically disposed within the interior of the rotor casing, with the stator core peripheral surface disposed proximate to the rotor magnets, separated from the magnets by a predetermined gap distance, such that relative motion of the rotor and stator causes magnetic flux from the magnets to electromagnetically interact with the stator winding; the rotor and stator being configured such that rotation of the rotor at and above a predetermined speed within the range of speeds tends to cause generation of heat that, if not dissipated, would raise the temperature of the magnets above a predetermined destructive level; and a cooling system for directing coolant flow into thermal contact with at least one of the winding and magnets, the cooling system generating sufficient coolant flow through a predetermined flow path at and above the predetermined speed to dissipate heat generated and maintain the temperature of the magnets below the predetermined destructive level.