Rotor lamination for an AC permanent magnet synchronous motor

Claim 2

A rotor for an AC permanent magnet 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 rotor laminations disposed in planes perpendicular to said axis, each of said laminations including a central shaft aperture, a plurality of conductive bar slots spaced apart along the periphery area of said lamination and respectively holding a conductive bar or material therein, a plurality of permanent magnet slots surrounding said central shaft aperture and substantially dividing said lamination into an inner and an outer portion and respectively securing a permanent magnet therein for establishing even magnetic poles on the periphery of said rotor by the magnetic field of said permanent magnets, a plurality of flux barrier slots respectively disposed in areas of said magnetic poles for setting up flux barriers to minimize flux leakage from said permanent magnets, each of said flux barrier slots configured in such a way that it is connected to an end of said magnet slot and, in cooperation with but without connection to said conductive bar slot, form 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 the lamination through said flux barrier to the periphery of the lamination, in order to simplify the manufacture and enhance the strength of said rotor lamination so as to provide a high-speed rotor, while minimizing the leakage flux from said permanent magnets.

Claim 3

A rotor in accordance with claim 1, wherein said even magnetic poles created by the magnetic field of said permanent magnets can be two poles, four poles or six poles.

Claim 4

A rotor in accordance with claim 1, wherein said rotor lamination further has an opening between each said conductive bar slot and the periphery of said lamination for minimizing power loss from said rotating magnetic field generated by said primary windings on the stator.

Claim 5

A rotor in accordance with claim 1, wherein said rotor lamination further includes a plurality of a second set of flux barrier slots each of which is connected to another end of one of said magnet slots and extend to form a narrow bridge across a quadrature line in cooperation with the adjacent flux barrier slot for further strengthening said rotor lamination.

Claim 6

A rotor in accordance with claim 4, wherein said narrow bridges can be directly formed between two magnet slots without using said second set of flux barrier slots.

Claim 7

A rotor in accordance with claim 1 or 4, wherein said flux barrier slots are either filled with a conductive material, such as aluminium, or nothing at all.

Claim 8

A rotor in accordance with claim 1, wherein said conductive bar slots are either filled with individual conductive bars or conductive casting material.

Claim 9

A rotor in accordance with claim 1, wherein said magnet slots are in rectangular shape for holding rectangular shaped permanent magnets.

Claim 10

A rotor in accordance with claim 1, wherein said flux barrier slots are in triangular shape having one side facing one of said conductive bar slots to form a bridge therebetween.

Claim 11

A rotor in accordance with claim 1, wherein said bridges are in a discontinuous ring configuration between said bar slots and said barrier slots so that positions of said barrier slots and said magnet slots can be changed or displaced with respect to the central axis during manufacture.

Claim 12

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.

Claim 13

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.

Claim 14

A rotor in accordance with claim 11, wherein the outer end of each said flux barrier slot faces the end of one of said squirrel bar slots, leaving a bridge or a ring configuration therebetween for resisting centrifugal force applied on said outer portion of said lamination during rotation and simplify the manufacture.

Claim 15

A rotor in accordance with claim 11, wherein said flux barrier slots are either air slots or filled with a conductive material, such as aluminium.

Claim 16

A rotor in accordance with claim 11, wherein said even magnetic poles formed by the magnetic field of said magnets can be two magnetic poles, or four magnetic poles or six magnetic poles.

Claim 17

A rotor in accordance with claim 14, wherein each of said laminations further includes a plurality of a second set of flux barrier slots, each of which is connected to the end of one of said magnet slots and extends forward to form a bridge across a quadrature line in cooperation with the adjacent similar flux barrier slot connected to an adjacent magnet slot for further strengthening said lamination.

Claim 18

A rotor in accordance with claim 11, wherein each of said flux barrier slots is a triangular shape, with one side facing the end of said squirrel cage bar slot to form a bridge thereunder.

Claim 19

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.

Claim 20

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.

Claim 21

A rotor lamination in accordance with claim 17, further including a plurality of second set of flux barrier slots, each connected to the end of one of said magnet slots and extending forward to form a bridge across a quadrature line in cooperation with another same flux barrier slot connected to an adjacent magnet slot for further strengthening said lamination.

Claim 22

A rotor lamination in accordance with claim 17, wherein the outer ends of said flux barrier slots either face the inner ends of said squirrel cage bar slots or disposed unsymmetrically with respect to the inner ends of said squirrel cage bar slots.