Patents by Inventor Khwaja M. Rahman
Khwaja M. Rahman has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 10003227Abstract: 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.Type: GrantFiled: July 1, 2015Date of Patent: June 19, 2018Assignee: GM Global Technology Operations LLCInventors: Sinisa Jurkovic, Mohammad Faizul Momen, Khwaja M. Rahman
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Publication number: 20180152066Abstract: A synchronous reluctance motor includes a stator and a rotor. The rotor is configured to rotate relative to the stator about a rotational axis. The rotor is spaced apart from the stator to define an air gap between the stator and the rotor and includes a rotor core defines an outermost rotor surface and an innermost rotor surface opposite the innermost rotor surface. The rotor core includes a plurality of ribs separating rotor cavities from each other and includes a plurality of rotor bridges separating the air gap and the rotor cavities. Permanent magnets are each disposed in one of the rotor cavities. The magnet surface area of the permanent magnets is less than cavity surface area of the rotor cavities. Each of the permanent magnets is adjacent to the outermost rotor surface to maximize magnetic saturation at the ribs and the rotor bridges.Type: ApplicationFiled: November 30, 2016Publication date: May 31, 2018Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Jingchuan Li, Khwaja M. Rahman, Robert T. Dawsey
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Patent number: 9899902Abstract: 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.Type: GrantFiled: May 18, 2015Date of Patent: February 20, 2018Assignee: GM Global Technology Operations LLCInventors: Sinisa Jurkovic, Khwaja M. Rahman
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Patent number: 9847704Abstract: An improved rotor assembly configured for magnets with differing lengths, and methods and systems for manufacturing the same. The rotor assembly may be created by selectively creating first and second tabs extending into apertures of lamination sheets. The first and second tabs may be selectively removed, depending on the different magnet lengths and the specific lamination sheet, according to one of a first finishing schedule and a second finishing schedule. The lamination sheets are stacked with any remaining first and second tabs, and other features, aligned.Type: GrantFiled: November 4, 2015Date of Patent: December 19, 2017Assignee: GM Global Technology Operations LLCInventors: Edward L. Kaiser, Peter J. Savagian, Khwaja M. Rahman
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Patent number: 9755462Abstract: 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.Type: GrantFiled: February 24, 2015Date of Patent: September 5, 2017Assignee: GM Global Technology Operations LLCInventors: Sinisa Jurkovic, Khwaja M. Rahman
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Publication number: 20170229928Abstract: A synchronous reluctance electric machine is described, and includes a stator including a plurality of electrical windings and a rotor disposed in a cylindrically-shaped void formed within the stator. The rotor includes a plurality of steel laminations assembled onto a shaft, wherein the shaft defines a longitudinal axis. Each of the steel laminations includes a plurality of poles and each of the poles includes a plurality of slots disposed near an outer periphery. The slots of the steel laminations are longitudinally aligned. A plurality of packets assembled from anisotropic material are disposed in the slots.Type: ApplicationFiled: May 4, 2016Publication date: August 10, 2017Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Constantin C. Stancu, Peter J. Savagian, Khwaja M. Rahman, Nitinkumar R. Patel, Robert T. Dawsey
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Publication number: 20170229934Abstract: An interior permanent magnet electric machine is described, and includes a stator including a plurality of electrical windings and a rotor disposed in a cylindrically-shaped void formed within the stator. The rotor includes a plurality of steel laminations assembled onto a shaft, wherein the shaft defines a longitudinal axis. Each of the steel laminations includes a plurality of poles and each of the poles includes a plurality of slots disposed near an outer periphery. The slots of the steel laminations are longitudinally aligned. A plurality of permanent magnets are disposed in a first subset of the slots, and plurality of packets assembled from anisotropic material are disposed in a second subset of the slots.Type: ApplicationFiled: May 4, 2016Publication date: August 10, 2017Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Khwaja M. Rahman, Constantin C. Stancu, Peter J. Savagian, Nitinkumar R. Patel, Robert T. Dawsey
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Patent number: 9712005Abstract: 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.Type: GrantFiled: December 2, 2014Date of Patent: July 18, 2017Assignee: GM Global Technology Operations LLCInventors: Khwaja M. Rahman, Sinisa Jurkovic, Edward L. Kaiser, Peter J. Savagian
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Patent number: 9520753Abstract: 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.Type: GrantFiled: July 24, 2013Date of Patent: December 13, 2016Assignee: GM Global Technology Operations LLCInventors: Khwaja M. Rahman, Edward L. Kaiser, Sinisa Jurkovic, Peter J. Savagian
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Publication number: 20160344274Abstract: 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.Type: ApplicationFiled: May 18, 2015Publication date: November 24, 2016Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Sinisa Jurkovic, Khwaja M. Rahman
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Publication number: 20160285334Abstract: An electric device and a stator assembly for the electric device includes a stator core defining a plurality of slots spaced from each other. The stator assembly includes a plurality of bar conductors disposed in each of the slots and arranged to present a first winding path, a second winding path and a third winding path. A first set of the bar conductors of the first, second and third winding paths are configured to receive current in a parallel circuit arrangement. The stator assembly also includes a plurality of electrical jumpers electrically connected to a predetermined number of the bar conductors such that an amount of current flowing through the first winding path and the third winding path is substantially the same and an amount of current flowing through the second winding path is different from the amount of current flowing through the first and third winding paths.Type: ApplicationFiled: March 26, 2015Publication date: September 29, 2016Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Paul F. Turnbull, Edward L. Kaiser, Matthew D. Laba, Khwaja M. Rahman, Rolf Blissenbach
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Publication number: 20160276885Abstract: 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.Type: ApplicationFiled: July 1, 2015Publication date: September 22, 2016Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Sinisa Jurkovic, Mohammad Faizul Momen, Khwaja M. Rahman
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Patent number: 9444298Abstract: A bar wound stator includes a stator core defining a plurality of slots. Bar-type conductors are disposed within each slot. Each slot includes a slot liner and an insulator cap. Each slot liner includes an end portion disposed against an inner wall surface, and side portions disposed against a first wall surface and a second wall surface respectively. Each insulator cap includes a base portion disposed against an outer wall surface, and side portions disposed against the first wall surface and the second wall surface respectively. The side portions of the insulator cap in each slot overlap the side portions of the slot liner in each slot along the first wall surface and the second wall surface respectively. Each slot includes a recessed feature in each of the first wall surface and the second wall surface to accommodate the overlapping side portions of the insulator cap and the slot liner.Type: GrantFiled: April 24, 2013Date of Patent: September 13, 2016Assignee: GM Global Technology Operations LLCInventors: Edward L. Kaiser, Paul Buchholz, Khwaja M. Rahman
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Publication number: 20160248286Abstract: An improved rotor assembly configured for magnets with differing lengths, and methods and systems for manufacturing the same. The rotor assembly may be created by selectively creating first and second tabs extending into apertures of lamination sheets. The first and second tabs may be selectively removed, depending on the different magnet lengths and the specific lamination sheet, according to one of a first finishing schedule and a second finishing schedule. The lamination sheets are stacked with any remaining first and second tabs, and other features, aligned.Type: ApplicationFiled: November 4, 2015Publication date: August 25, 2016Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Edward L. Kaiser, Peter J. Savagian, Khwaja M. Rahman
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Publication number: 20160248282Abstract: 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.Type: ApplicationFiled: February 24, 2015Publication date: August 25, 2016Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Sinisa Jurkovic, Khwaja M. Rahman
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Patent number: 9379586Abstract: 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.Type: GrantFiled: April 24, 2013Date of Patent: June 28, 2016Assignee: GM Global Technology Operations LLCInventors: Khwaja M. Rahman, Sinisa Jurkovic, Peter J. Savagian
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Publication number: 20160126789Abstract: A permanent magnet (PM) motor includes a stator defining an inner stator opening. The inner stator opening extends along a stator axis. The PM motor further includes a rotor disposed inside the stator. The stator includes a plurality of lamination segments stacked together along the stator axis. Each lamination segment includes an annular stator body and teeth extending from the annular stator body toward the stator axis. The teeth are spaced apart from one another so as to define a plurality of slots arranged annularly about the stator axis. The stator defines slot openings arranged annularly about the stator axis. At least one of the lamination segments is rotationally offset relative to another lamination segments so that at least one of the slot openings is circumferentially offset from another slot openings in the other lamination segment.Type: ApplicationFiled: October 31, 2014Publication date: May 5, 2016Inventors: Mohammad Faizul Momen, Khwaja M. Rahman
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Publication number: 20160056676Abstract: A partially segmented rotor assembly for an electric motor and a method for the same is provided. The partially segmented rotor assembly includes a first rotor segment and a plurality of second rotor segments. The first rotor segment has a plurality of first poles wound with a wire and defines a first circumferential gap between the wire of each adjacent pair of the first poles. Each second rotor segment has a second pole wound with the wire and is rigidly attached to the first rotor segment in a respective one of the first circumferential gaps to form a plurality of second circumferential gaps between the wire of each first pole and the wire of the adjacent second poles. The first and second rotor segments are configured to cooperate with one another to minimize the second circumferential gaps.Type: ApplicationFiled: August 25, 2014Publication date: February 25, 2016Inventors: Terence G. Ward, Constantin C. Stancu, Khwaja M. Rahman, Srihari Gangaraj, Brooks S. Mann
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Patent number: 9154019Abstract: A hub assembly for an electric machine includes a rotor hub and a machine rotor. Rotation of the machine rotor generates an electromagnetic (EM) field. The hub assembly includes a resolver rotor that encodes an angular position of the machine rotor as a set of resolver signals. An EM field barrier ring between the resolver rotor and the rotor hub adds a magnetic barrier between the machine rotor and the resolver rotor to reduce noise in the resolver signals. The resolver rotor may be bonded to the EM field barrier ring. The EM field barrier ring may have an L-shaped cross section, and may be press-fitted into a pocket of the rotor hub. A vehicle includes a transmission having an input member and an electric machine having a rotor shaft connected to the input member of the transmission. The electric machine includes the hub assembly noted above.Type: GrantFiled: June 12, 2012Date of Patent: October 6, 2015Assignee: GM Global Technology Operations LLCInventors: Brian Gallert, Khwaja M. Rahman, Matthew D. Laba, Paul F. Turnbull, Brian Schulze
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Patent number: 9130422Abstract: 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.Type: GrantFiled: March 8, 2013Date of Patent: September 8, 2015Assignee: GM Global Technology Operations LLCInventors: Khwaja M. Rahman, Sinisa Jurkovic