Gm Global Technolgoy Operations, Inc.

Sinisa Jurkovic

Khwaja M Rahman

Edward L Kaiser

Peter James Savagian

Qiang Niu

Xu Han

Xinyu Zhou

John C Morgante

Amanda Luedtke

Brendan M Conlon

Constantin C Stancu

Jihoon Jang

Dwarakanath V Simili

Mohammad Faizul Momen

Trevor John Blohm

An apparatus or assembly for forming injection molded magnets in permanent magnet rotors or laminations for such rotors. The assembly includes a plurality of platens defining an axial boundary of a die cavity and a plurality of support shoes that are radially moveable between a closed position defining a radial boundary of the die cavity, and an open position creating a gap between the rotor core and the plurality of support shoes. The assembly has an injection system for filling at least one of the plurality of voids of the rotor core with a magnetic slurry, and a plurality of alignment magnets configured to magnetically align the magnetic slurry.

Apparatus for injection molding rotor magnets

An interior permanent magnet machine includes a rotor having a central axis and a plurality of axial segments. The axial segments include a first axial segment and a second axial segment positioned adjacent to each other in an axial direction. Each of the axially-spaced segments includes at least one pole defining a respective angular configuration characterized by respective first, second and third angles. The first axial segment defines a first set of angular configurations and the second axial segment defines a second set of angular configurations. The rotor is configured to have an axially asymmetric configuration such that the first set of angular configurations is different from the second set of angular configurations.

Axially asymmetric configuration for interior permanent magnet machine

An internal permanent magnet machine includes a wound stator, and a rotor core. The rotor core includes a plurality of first pole cavities, and a plurality of second pole cavities. One of a plurality of magnets is disposed within each of the pole cavities, and is injection molded into their respective cavity. The first pole cavities and the second pole cavities are each arranged in a pre-defined configuration, such that each pole cavity of the first pole cavities is identically positioned with one of the pole cavities of the second pole cavities within their respective pre-defined configurations, to define a corresponding pair of pole cavities. The pole cavity of the first pole cavities and the pole cavity of the second pole cavities of at least one of the corresponding pair of pole cavities define a different shape relative to each other.

Pole to pole variation in shape of injection molded magnets of internal permanent magnet machines

An interior permanent magnet machine includes a wound stator, and a rotor core defining a plurality of pole cavities. Each of the pole cavities includes a cross section, perpendicular to a central axis of rotation, that defines a cross sectional shape having a centerline. The cross sectional shape of each of the pole cavities includes a radially inner barrier portion, a radially outer barrier portion, and a central portion. The centerline of the cross sectional shape of each of the radially outer barrier portion and the radially inner barrier portion, of each pole cavity, is defined by a generally arcuate segment. The centerline of the cross sectional shape of the central portion, of each pole cavity, is defined by a linear segment. One of a plurality of rare earth magnets, having no heavy rare earth elements, is disposed within the central portion of one of the plurality of pole cavities.

Rotor geometry for interior permanent magnet machine having rare earth magnets with no heavy rare earth elements

An interior permanent magnet machine includes a rotor having a plurality of slots. First and second slots are disposed in a first pole and the third and fourth slots are disposed in a second pole. A first angle is defined between respective centerlines of the first and second slots. A second angle is defined between respective centerlines of the third and fourth slots. The first angle is configured to be sufficiently different from the second angle so that torque ripple is reduced. Thus the rotor is configured such that the angular configuration of slots in a first pole is different from the angular configuration of slots in a second pole of the rotor.

Interior permanent magnet machine with pole-to-pole asymmetry of rotor slot placement

An electric machine assembly includes an electric machine having a stator and a rotor. The stator has stator windings at a stator winding temperature (t) and the rotor is configured to rotate at a rotor speed (&#x3c9;). A controller is operatively connected to the electric machine and has a processor and tangible, non-transitory memory on which is recorded instructions for executing a method for determining stator winding resistance. The controller is configured to determine a high-speed resistance factor (r) which is based at least partially on the torque command (T*), the stator winding temperature (t), the rotor speed (&#x3c9;), a characterized torque error and the number of pole pairs (P). The controller may determine a total resistance value (R) based on a weighting factor (k), the high-speed resistance factor (r) and the low-speed resistance factor (r).

Determination of stator winding resistance in an electric machine

A method and assembly for forming a rotor include forming a rotor core having a plurality of voids and placing the formed rotor core into a die cavity. The method includes moving a plurality of support shoes to define an outer diameter of the die cavity, and injecting at least one of the plurality of voids with a magnetic slurry. At least one permanent magnet is formed from the magnetic slurry by applying pressure to the rotor core and the magnetic slurry within the die cavity and by applying a magnetic field to align the magnetic slurry. After forming the at least one permanent magnet within the rotor core, the plurality of support shoes are retracted and the rotor core removed with the at least one permanent magnet formed therein.

Method for injection molding rotor magnets

A stator assembly includes a plurality of stator slots defining multiple slot layers. The assembly includes a plurality of hairpins each having a respective first leg positioned in one of the multiple slot layers and a respective second leg positioned in another of the multiple slot layers. Each hairpin is configured to allow a current to flow from the respective first leg to the respective second leg. The plurality of hairpins is divided into multiple hairpin layers. The hairpins form multiple winding sets, such as first, second, third and fourth winding sets. Each of the winding sets at least partially includes the hairpins from at least two of the multiple hairpin layers. The multiple slot layers may include six slot layers. The multiple hairpin layers may include six hairpin layers. Thus, at least one of the hairpin layers may be 'shared' by two winding sets.

Stator assembly with winding sets having hairpins from multiple hairpin layers

A stator assembly includes a plurality of stator slots defining a plurality of slot layers. The assembly includes a plurality of hairpins each having respective first and second legs positioned in respective ones of the slot layers. Each of the hairpins is one of a short-pitched coil, a long-pitched coil and a full-pitched coil. The short-pitched, long-pitched and full-pitched coils are configured to extend over a first, second and third number of the stator slots, respectively. The hairpins may be divided into first, second, third, fourth, fifth and sixth hairpin layers. One of the hairpin layers includes at least one short-pitched coil, and another of the hairpin layers includes at least one long-pitched coil. The first, third and fifth hairpin layers each may include at least two short-pitched coils while the second, fourth and sixth hairpin layers each may include at least two long-pitched coils.

Bar wound stator winding layout with long-pitched and short-pitched coils

A rotor core for an internal permanent magnet machine includes at least one ferrite pole and at least one rare earth pole, arranged radially about an axis in alternating relationship. The ferrite poles define a plurality of first pole cavities, and the rare earth poles define a plurality of second pole cavities. One of a plurality of ferrite magnets is disposed within each of the first pole cavities of the ferrite poles, and one of a plurality of rare earth magnets is disposed within each of the second pole cavities of the rare earth poles.

Interior permanent magnet machine having a mixed rare earth magnet and ferrite magnet rotor

An interior permanent magnet machine includes a stator including a plurality of electrical conductors. The interior permanent magnet machine further includes a rotor concentrically disposed in relation to the stator. The rotor is configured to rotate relative to the stator about a rotational axis and includes a plurality of polar pieces arranged annularly about the rotational axis. At least one of the polar pieces includes a magnetic layer configured to magnetically interact with the electrical conductors. The magnetic layer has a substantially conic section shape.

Interior permanent magnet machine

An electric machine is provided with a rotor configured to be rotatable within a stator. A first and second tooth are disposed circumferentially along an outer perimeter of the rotor and at least partially define a first slot. The first and the second tooth define a respective first and second outer edge extending between a respective tooth base and a respective tooth tip. An arc radius from the origin to the outer perimeter of the rotor varies along the first outer edge of the first tooth, thereby creating a first non-uniform gap between the rotor and the stator. The arc radius from the origin to the outer perimeter of the rotor varies along the second outer edge of the second tooth, thereby creating a second non-uniform gap between the rotor and the stator. The rotor geometry is configured to reduce torque ripple without skewing either the rotor or the stator.

Rotor geometry for reduction of torque ripple in a wound field machine

An interior permanent magnet machine includes a rotor having a plurality of slots. First and second slots are disposed in a first pole and the third and fourth slots are disposed in a second pole. A first barrier is defined by the first, second, third and fourth slots. The slots are configured to be symmetric relative to their respective pole axes. A first angle is defined between the first and second slots. A second angle is defined between the third and fourth slots. The first angle is configured to be sufficiently different from the second angle so that torque ripple is minimized. Thus the rotor is configured such that the angular configuration of slots in a first pole is different from the angular configuration of slots in a second pole of the rotor.

An interior permanent magnet machine includes a rotor formed with a plurality of slots that are substantially arc-shaped and referred to herein as arc segments. A first layer of arc segments are disposed in a first pole. The first layer defines a first configuration relative to a first arc center. A second layer of arc segments are disposed in a second pole. The second layer defines a second configuration relative to a second arc center. The rotor is configured such that the first configuration is different from the second configuration, thereby exhibiting pole-to-pole asymmetry. The first configuration is sufficiently different from the second configuration such that torque ripple may be minimized. In one embodiment, the first layer includes first, second and third arc segments. The rotor may be configured such that the second arc segment is radially offset relative to the first and third arc segments.

Pole-to-pole asymmetry in interior permanent magnet machines with arc-shaped slots

A rotor core for an Internal Permanent Magnet (IPM) machine includes a cavity having a magnet disposed therein. The cavity defines an air slot adjacent a radially outermost edge of the magnet disposed therein. A leakage flux path extends across the air slot and connects opposing sides of the cavity. The leakage flux path is oriented in an approximate tangential relationship relative to an axis of rotation of the rotor core, and is angled relative to the radially outermost edge of the magnet disposed within the cavity to direct flux away from the magnet. The cavity further includes an air pocket disposed along a radial inner surface of the magnet relative to the axis of rotation, adjacent the air slot of the cavity.

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Sterling Heights, MI, United States of America

Sinisa Jurkovic