Rotor lamination for an AC permanent magnet synchronous motor

A rotor for an AC permanent magnetic synchronous motor having a stator with a primary winding for producing a rotating magnetic field, comprising:

• a central rotor shaft with a longitudinal axis,
• a plurality of magnetically permeable annular laminations disposed in planes perpendicular to said axis,
• each of said laminations including a central shaft aperture, a plurality of squirrel cage bar slot spaced apart around the periphery area of said lamination and respectively holding a conductive bar or material therein, each of which has an opening toward the outside the minimizing power loss from said rotating magnetic field, a plurality of permanent magnet slots surrounding said central shaft aperture and substantially dividing said lamination into an inner portion and an outer portion and respectively holding a permanent magnet therein for establishing even magnetic poles on the periphery of said rotor by the magnetic field of said magnets, a plurality of flux barrier slots respectively located in areas of said magnetic poles for establishing flux barriers to minimize leakage flux from said magnets, each of which is connected to an end of one of said magnet slots, and extends outwardly to the periphery area of said lamination without connection of any kind to said squirrel cage bar slots to form a bridge between said inner portion and outer portion of said lamination, said bridge being substantially perpendicular to a radial line extending from the center of said lamination through said flux barrier to the periphery area of said laminating to enhance the strength of said lamination and minimize the leakage flux from said permanent magnets.

A rotor lamination which is used in a permanent magnet rotor, said rotor including a stack of said rotor laminations for a high speed AC permanent magnet synchronous motor, comprising:

• a circular central aperture for holding a rotor shaft,
• a plurality of squirrel cage bar slots spaced apart around the periphery area of said lamination for respectively holding a conductive bar therein, each of said bar slots having an opening facing outside for minimizing power loss from the rotating magnetic field produced by a primary winding on a motor stator,
• a plurality of permanent magnet slots surrounding said central aperture and substantially dividing said lamination into an inner portion and an outer portion for holding permanent magnets therein which establish even magnetic poles on the periphery of said lamination,
• a plurality of flux barrier slots respectively located in areas of said magnetic poles for establishing flux barriers to minimize leakage flux from said permanent magnets, each of said flux barrier slots connected to an end of said magnet slot and extending outwardly to the peripheral area of said lamination without connection to any of said squirrel cage bar slots so as to form a bridge or a ring configuration between said inner portion and outer portion of said lamination, said bridge being substantially perpendicular to a radial line extending from the center of said lamination via said flux barrier to the periphery of said lamination, to enhance the strength of said lamination.