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: 8613131Abstract: Methods are provided for forming/inserting a magnet in a rotor. One method includes coating a plurality of magnetizable particles with a non-metallic material, inserting the coated particles in a rotor, and magnetizing the coated particles. Another method includes inserting a plurality of magnetizable particles into a rotor, submersing the rotor in motor varnish or another viscous, non-metallic material to coat the particles, and magnetizing the particles. Yet another method includes inserting a plurality of magnetizable particles in a rotor, inserting a non-metallic material into the rotor, mixing the particles and non-metallic material to form a mixture, curing the mixture to coat each particle with non-metallic material, and magnetizing the particles.Type: GrantFiled: April 20, 2010Date of Patent: December 24, 2013Assignee: GM Global Technology Operations LLCInventors: Terence G. Ward, Khwaja M. Rahman
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Publication number: 20130328454Abstract: 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: ApplicationFiled: June 12, 2012Publication date: December 12, 2013Applicant: GM GLOBAL TECHNOLOGY OPERATION LLCInventors: Brian Gallert, Khwaja M. Rahman, Matthew D. Laba, Paul F. Turnbull, Brian Schulze
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Patent number: 8602938Abstract: A hybrid vehicle includes an internal combustion engine, a ferrite magnet motor and a rare earth magnet motor. When the vehicle is cruising at a steady speed, an electrically variable transmission mode of a transmission configures the rare earth magnet motor to provide a reaction force to the ferrite magnet motor so that the ferrite magnet motor operates at a high speed/low torque condition to minimize torque dependent losses in the ferrite magnet motor. When the vehicle is accelerating at higher speeds, a first torque transmitting mechanism provides a reaction torque to the ferrite magnet motor to eliminate the torque dependent losses in the ferrite magnet motor.Type: GrantFiled: July 6, 2012Date of Patent: December 10, 2013Assignee: GM Global Technology Operations LLCInventors: Brendan M. Conlon, Khwaja M. Rahman, Trevor John Blohm, Sinisa Jurkovic
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Publication number: 20130270957Abstract: 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.Type: ApplicationFiled: April 17, 2012Publication date: October 17, 2013Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Sinisa Jurkovic, Khwaja M. Rahman
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Publication number: 20130270952Abstract: A permanent magnet machine is provided with a rotor positioned at least partially within a stator. The rotor includes first and second ring segments oriented axially around a central axis. The rotor defines first and second configurations in the first and second ring segments, respectively. The first configuration is sufficiently different from the second configuration such that torque ripple may be minimized. A first layer of slots, defining a slot outer edge, may be formed in the rotor. In one embodiment, a stator-to-slot gap varies between the first and second ring segments. In another embodiment, a stator-rotor gap varies between the first and second ring segments. In another embodiment, a bridge thickness varies between the first and second ring segments. Thus the rotor exhibits axial asymmetry.Type: ApplicationFiled: April 17, 2012Publication date: October 17, 2013Inventors: Sinisa Jurkovic, Khwaja M. Rahman, Xinyu Zhou, Xu Han, Qiang Niu
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Patent number: 8542085Abstract: A high frequency rotary transformer for an electrical machine includes a primary transformer component having a primary transformer winding, and a secondary transformer component having a secondary transformer winding. The primary transformer winding is configured to be coupled to a DC power source via a DC to AC converter. The secondary transformer winding is configured to be coupled to a winding of the rotor. Each of the primary and secondary transformer components are mechanically coupled to either the stator or the rotor. The secondary transformer component is configured to rotate with respect to the primary transformer component to produce a magnetic flux via the primary transformer winding and the secondary transformer winding.Type: GrantFiled: February 28, 2011Date of Patent: September 24, 2013Assignee: GM Global Technology Operations LLCInventors: Constantin C. Stancu, Peter J. Savagian, Khwaja M. Rahman, Robert T. Dawsey, Erik Hatch
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Patent number: 8487494Abstract: An interior permanent magnet machine is provided with a rotor that includes a plurality of slots and at least one barrier defined by the plurality of slots. A plurality of first and second magnets are disposed within the barrier. The rotor is configured such that at least one of the first magnets is located at a different radial distance from the center of the rotor relative to at least one of the second magnets. The rotor may be configured to produce an averaging effect similar to that achieved through traditional skewing of rotor magnets. The rotor includes a plurality of poles defined by respective pole axes in the rotor and may be configured to reflect radial asymmetry between poles (pole-to-pole) and/or radial asymmetry within a pole.Type: GrantFiled: September 21, 2011Date of Patent: July 16, 2013Assignee: GM Global Technology Operations LLCInventors: Sinisa Jurkovic, Khwaja M. Rahman, Xinyu Zhou, Xu Han, Qiang Niu
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Publication number: 20130147299Abstract: 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.Type: ApplicationFiled: December 9, 2011Publication date: June 13, 2013Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Khwaja M. Rahman, Sinisa Jurkovic, Edward L. Kaiser, Peter J. Savagian
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Publication number: 20130147302Abstract: 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.Type: ApplicationFiled: December 9, 2011Publication date: June 13, 2013Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Khwaja M. Rahman, Sinisa Jurkovic
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Publication number: 20130147309Abstract: 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.Type: ApplicationFiled: December 7, 2011Publication date: June 13, 2013Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Khwaja M. Rahman, Constantin C. Stancu, Sinisa Jurkovic, Xinyu Zhou, Qiang Niu, Xu Han
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Publication number: 20130147303Abstract: An interior permanent magnet machine includes a rotor configured to magnetically interact with a stator. First and second dividers are integrally formed within the rotor and configured to create a first layer of three respective first segments. Each of the respective first segments may be substantially arc-shaped. A plurality of first magnets may be positioned in the first layer. The first magnets may be substantially arc-shaped and defined around an arc center. A third and a fourth divider may be integrally formed within the rotor and configured to create a second layer of three respective second segments. The placement of dividers or structural webs provides for increased rotational speed and reduced rotational stress compared to an undivided arc-shaped magnet configuration.Type: ApplicationFiled: July 27, 2012Publication date: June 13, 2013Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Edward L. Kaiser, Khwaja M. Rahman, Sinisa Jurkovic
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Patent number: 8456053Abstract: An assembly for providing electrical insulation in a stator core of a vehicular electric machine is provided. The stator core has a channel and the assembly comprises a first conductive element disposed through the channel, and a second conductive element disposed through the channel and substantially adjacent to the first conductive element. The assembly also comprises a first electrically insulating film having a first end residing between the first and second conductive elements.Type: GrantFiled: August 28, 2009Date of Patent: June 4, 2013Assignee: GM Global Technology Operations LLCInventors: Edward L. Kaiser, Khwaja M. Rahman
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Publication number: 20130069470Abstract: An interior permanent magnet machine is provided with a rotor that includes a plurality of slots and at least one barrier defined by the plurality of slots. A plurality of first and second magnets are disposed within the barrier. The rotor is configured such that at least one of the first magnets is located at a different radial distance from the center of the rotor relative to at least one of the second magnets. The rotor may be configured to produce an averaging effect similar to that achieved through traditional skewing of rotor magnets. The rotor includes a plurality of poles defined by respective pole axes in the rotor and may be configured to reflect radial asymmetry between poles (pole-to-pole) and/or radial asymmetry within a pole.Type: ApplicationFiled: September 21, 2011Publication date: March 21, 2013Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Sinisa Jurkovic, Khwaja M. Rahman, Xinyu Zhou, Xu Han, Qiang Niu
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Patent number: 8362732Abstract: A method of detecting a phase winding fault in a multi-phase electric machine is executable via a motor controller, and includes measuring feedback signals of the machine, including each phase current, and generating reference phase voltages for each phase. The method includes calculating a predetermined voltage value using the feedback signals and reference phase voltages, and comparing the voltage value to a corresponding threshold to determine the fault. A control action is executed when the voltage value exceeds the corresponding threshold. The voltage value is one or more of: a ratio of a normalized negative sequence voltage to a modulation index, an RMS voltage for each phase, and total harmonic distortion of each phase current. An apparatus detects the fault, and includes a motor controller and an algorithm as set forth above. The apparatus may include a voltage inverter for generating a multi-phase alternating current output for powering the machine.Type: GrantFiled: February 2, 2010Date of Patent: January 29, 2013Assignee: GM Global Technology Operations LLCInventors: Mohammad N. Anwar, S. M. N. Hasan, Khwaja M. Rahman, Silva Hiti, Steven E. Schulz, Sean E. Gleason
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Publication number: 20130020896Abstract: A rotor for a permanent magnet electric machine includes an axis of rotation, an outer surface, and a cross-section orthogonal to the axis of rotation with a non-circular contour of the outer surface defined by a plurality of radii angularly distributed around the axis of rotation.Type: ApplicationFiled: July 19, 2011Publication date: January 24, 2013Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Xinyu Zhou, Sinisa Jurkovic, Qiang Niu, Khwaja M. Rahman, Xu Han, John C. Morgante
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Publication number: 20120293105Abstract: An electric motor includes a stator configured to receive electrical energy and generate an electromagnetic field in accordance with the electrical energy received. A rotor is in electromagnetic communication with the stator and is configured to rotate in accordance with the electromagnetic field generated by the stator. The rotor includes a plurality of poles including a first set of poles and a second set of poles. The first set of poles defines a first slot and the second set of poles defines a second slot that has a different configuration than the first slot to reduce a torque ripple effect. The electric motor may be used in a system having a power source configured to output direct current energy and an inverter configured to convert direct current energy to alternating current energy.Type: ApplicationFiled: May 20, 2011Publication date: November 22, 2012Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Sinisa Jurkovic, Khwaja M. Rahman, Edward L. Kaiser, Xinyu Zhou, Qiang Niu, Xu Han
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Publication number: 20120286613Abstract: A permanent magnet motor includes a permanent magnet rotor, a stator surrounding the rotor having a plurality of teeth radially inwardly oriented toward a longitudinal axis of the stator wherein each tooth has a tooth length and a tooth tip surface geometry. An asymmetric air gap is defined by variations in the tooth lengths and tooth tip surface geometries.Type: ApplicationFiled: May 9, 2011Publication date: November 15, 2012Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: SINISA JURKOVIC, XINYU ZHOU, QIANG NIU, KHWAJA M. RAHMAN, JOHN C. MORGANTE, XU HAN, EDWARD L. KAISER
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Publication number: 20120218069Abstract: A high frequency rotary transformer for an electrical machine includes a primary transformer component having a primary transformer winding, and a secondary transformer component having a secondary transformer winding. The primary transformer winding is configured to be coupled to a DC power source via a DC to AC converter. The secondary transformer winding is configured to be coupled to a winding of the rotor. Each of the primary and secondary transformer components are mechanically coupled to either the stator or the rotor. The secondary transformer component is configured to rotate with respect to the primary transformer component to produce a magnetic flux via the primary transformer winding and the secondary transformer winding.Type: ApplicationFiled: February 28, 2011Publication date: August 30, 2012Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLCInventors: Constantin C. STANCU, Peter J. SAVAGIAN, Khwaja M. RAHMAN, Robert T. DAWSEY, Erik HATCH
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Patent number: 8231504Abstract: A powertrain is provided that includes an engine as well as a transmission having an input member and an output member. The powertrain also includes a motor/generator that has an energizable stator, a first rotor and a second rotor (i.e., a dual rotor motor). Both of the rotors are rotatable via energization of the stator. A first torque-transmitting mechanism, referred to as the engine clutch, is selectively engagable to connect the engine for common rotation with one of the first and the second rotors. A second torque-transmitting mechanism, referred to as the motor clutch, is selectively engagable to connect the first rotor for common rotation with the second rotor. The transmission input member is continuously connected for common rotation with the other of the first and second rotors.Type: GrantFiled: February 16, 2009Date of Patent: July 31, 2012Assignee: GM Global Technology Operations LLCInventors: James D. Hendrickson, Brendan M. Conlon, Khwaja M. Rahman
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Patent number: 8174158Abstract: In general, the various embodiments are directed to a permanent magnet machine (“PM machine”), and more specifically an internal permanent magnet machine (“IPM machine”) that includes rotor magnets configured asymmetrically with respect to the rotor periphery, thereby producing an averaging effect similar to that achieved through traditional skewing of the rotor magnets. In alternate embodiments, the span, placement and/or shape of the magnets may vary from one pole to the next.Type: GrantFiled: February 20, 2009Date of Patent: May 8, 2012Assignee: GM Global Technology Operations LLCInventors: Khwaja M. Rahman, Edward L. Kaiser, Peter J. Savagian