Patents by Inventor James Nagashima

James Nagashima 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).

  • Publication number: 20080061525
    Abstract: A vehicular wheel assembly includes a first bearing component configured to be coupled to a frame of a vehicle, a second bearing component rotatably coupled to the first bearing component, and a brake mechanism coupled to the second bearing component. The motor includes a stator and a rotor. The stator is coupled to the first bearing component and the rotor is coupled to the second bearing component such that rotation of the rotor relative to the stator causes the second bearing component to rotate relative to the first bearing component. The brake mechanism is between the motor and the frame and is configured to slow the rotation of the second bearing component and the rotor.
    Type: Application
    Filed: September 7, 2007
    Publication date: March 13, 2008
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Terence Ward, James Nagashima, Michael Milani, Khwaja Rahman
  • Publication number: 20070132415
    Abstract: Methods and apparatus are provided for generating zero-sequence voltages based on voltage commands and a motor output signal. At least one of the methods includes, but is not limited to, receiving a torque command and generating three-phase voltage commands based on the torque command. The method also includes, but is not limited to, generating a motor output responsive to the three-phase voltage commands and generating three-phase zero-sequence voltage samples based on the three-phase voltage commands and the motor output.
    Type: Application
    Filed: December 14, 2005
    Publication date: June 14, 2007
    Inventors: Nitinkumar Patel, Bon-Ho Bae, James Nagashima
  • Publication number: 20060174642
    Abstract: In order to provide a modular arrangement, an inverter for an electric traction motor used to drive an automotive vehicle is positioned in proximity with the traction motor. The inverter is located within a compartment adjacent to one end of the electric traction motor and is cooled in a closed system by spraying a liquid coolant directly onto the inverter. The liquid coolant absorbs heat from the inverter and is cooled by a heat exchange arrangement comprising a reservoir with pipes carrying a second coolant from the radiator of the automotive vehicle. In a preferred embodiment, the coolant is collected from the inverter in an annular reservoir that is integral with the compartment containing the inverter. In accordance with one embodiment of the cooling arrangement, heat from the inverter vaporizes the liquid coolant by absorbing heat from the inverter during a phase change from a liquid to a vapor.
    Type: Application
    Filed: February 9, 2005
    Publication date: August 10, 2006
    Inventors: James Nagashima, Karl Conroy, Eric Ostrom, Gregory Smith, George John, David Tang, Terence Ward
  • Publication number: 20060164028
    Abstract: A double-ended inverter system for a vehicle having a load, a first energy source, and a first inverter system coupled to the first energy source and adapted to drive the load. The double-ended inverter system further having a secondary energy source, a second capacitor coupled in parallel to the secondary energy source, and a second inverter system coupled to the secondary energy source and adapted to drive the load. A controller includes an output coupled to the first inverter system and the second inverter system for providing at least one pulse width modulated signal to the first inverter system and the second inverter system.
    Type: Application
    Filed: January 26, 2005
    Publication date: July 27, 2006
    Inventors: Brian Welchko, James Nagashima
  • Publication number: 20060164027
    Abstract: A method of providing a unified power control of a motor including providing a first inverter system, a second inverter system, and a motor coupled therebetween; coupling the first inverter system coupled to a first energy source; coupling the second inverter system coupled to a secondary energy source; generating a first pulse width modulated signal; and generating a second pulse width modulated signal. The first inverter system and the second inverter system are driven with the first pulse width modulated signal and the second pulse width modulated signal respectively in order to control a fundamental component of an output voltage of the first inverter system and the second inverter system to control the motor.
    Type: Application
    Filed: January 26, 2005
    Publication date: July 27, 2006
    Inventors: Brian Welchko, James Nagashima
  • Publication number: 20060097702
    Abstract: A method of controlling an IPM machine having a salient rotor. Stator terminal signals are measured and rotated to obtain synchronous reference frame current signals. A rotor position is estimated based on an impedance generated using the rotor and included in the current signals. The estimated rotor position is used to control the machine. An alternator-starter system in which this method is used can provide high cranking torque and generation power over a wide speed range while providing operational efficiency.
    Type: Application
    Filed: November 9, 2004
    Publication date: May 11, 2006
    Inventors: James Nagashima, Khwaja Rahman, Nitinkumar Patel, Steven Schulz, Terence Ward, Stanley Fujii
  • Publication number: 20050275302
    Abstract: A machine includes a stator and a rotor having a plurality of poles. Each pole is formed at least in part by a plurality of permanent magnets recessed within the rotor at a predetermined distance from an outer surface of the rotor. The distance is predetermined to minimize rotor flux variation near the outer surface during rotation of the rotor relative to the stator. Eddy current losses are thereby reduced.
    Type: Application
    Filed: June 14, 2004
    Publication date: December 15, 2005
    Inventors: Khwaja Rahman, James Nagashima
  • Publication number: 20050231152
    Abstract: A hybrid/electric vehicle including a battery system connected to a DC charger, an inverter coupled to the battery system, and an electric AC motor coupled to the inverter. The motor has first, second and third stator windings corresponding to first, second and third phases of the motor. Each stator winding has first and second leads, and the inverter has a plurality of switches that are connected to provide current to the stator windings at the first and second leads.
    Type: Application
    Filed: April 19, 2004
    Publication date: October 20, 2005
    Inventors: Brian Welchko, James Nagashima, Khwaja Rahman
  • Patent number: 6892796
    Abstract: A power module with heat sources wherein the heat is dissipated by a heat sink. The heat sink includes a manifold with coolant flowing therein. An opening on the manifold enables the coolant to come in direct contact with a base plate of the power module. The power module being retained on the heat sink by a plurality of spring clips.
    Type: Grant
    Filed: February 23, 2000
    Date of Patent: May 17, 2005
    Assignee: General Motors Corporation
    Inventors: James Nagashima, Terence G. Ward
  • Publication number: 20050073272
    Abstract: The present invention includes a method for managing processor execution time in a motor controller. The method includes receiving motor speed data, comparing the received motor speed data to predetermined motor speed ranges, determining a motor speed range based on the comparison, and modulating an inverter switching frequency of the motor controller processor based on the motor speed range. The step of receiving motor speed data may include receiving machine terminal information, processing the received machine terminal information utilizing a sensorless control algorithm, and determining motor speed data based on the processed information. The step of modulating the inverter switching frequency may include determining a modified inverter switching frequency value based on the determined motor speed range and providing the modified inverter switching frequency value to a processor control algorithm.
    Type: Application
    Filed: October 1, 2003
    Publication date: April 7, 2005
    Inventors: James Nagashima, Thomas O'Meara, Nitinkumar Patel, Steven Schulz
  • Publication number: 20050057948
    Abstract: A power supply generates alternating current and direct current from a constant-voltage source. A multi-phase pulse width modulation voltage source inverter is connected across the source to output multi-phase alternating current. At least one waveform generator is bridged in parallel with the inverter, with each waveform generator outputting zero-sequence waveform current compensated to maintain the multi-phase current within a predetermined tolerance from a desired set point. A rectifier receives the waveform current and generates direct current.
    Type: Application
    Filed: September 17, 2003
    Publication date: March 17, 2005
    Inventors: Douglas Carlson, John Hsu, James Nagashima, Constantin Stancu, Donald Adams, Gui-Jia Su, Gregory Smith
  • Publication number: 20050035672
    Abstract: Methods and apparatus are provided for an axial electric motor. The apparatus comprises, a stator having coils thereon for producing a magnetic field, a rotor rotated by the magnetic field, an output shaft coupled to the rotor, and a ring incorporating a coolant channel circumferentially engaging the stator for absorbing heat and reaction torque from the stator. It is preferable that that the ring have inwardly extending teeth that mesh with the coils on the stator. The space between the teeth and the coils is preferably filled with a substantially solid thermally conductive material to transmit stator reaction torque to the teeth and cool the stator. The coils are preferably formed from a flat ribbon a portion of whose principal surface is perpendicular to the teeth. A supporting frame is desirably fixedly coupled to the ring and rotatably coupled to the output shaft.
    Type: Application
    Filed: July 29, 2004
    Publication date: February 17, 2005
    Inventors: Terence Ward, Khwaja Rahman, James Nagashima, Fabio Crescimbini, Federico Caricchi, Giorgio Lucchi
  • Publication number: 20050035678
    Abstract: Methods and apparatus are provided for an axial electric motor. The apparatus comprises, a stator having coils thereon for producing a magnetic field, a rotor rotated by the magnetic field, and an output shaft coupled to the rotor. The rotor includes a magnetic and non-magnetic component. The non-magnetic component has a lower density than the magnetic component. One or both of the rotor components have apertures therein for ventilation and weight reduction. Permanent magnets are desirably mounted on the magnetic component of the rotor facing the stator and portions of the rotor behind the permanent magnets are hollowed out to be thinner than portions of the rotor between the permanent magnets. This reduces rotor weight without significantly affecting magnetic flux density in the rotor or motor torque.
    Type: Application
    Filed: July 29, 2004
    Publication date: February 17, 2005
    Inventors: Terence Ward, Khwaja Rahman, James Nagashima, Fabio Crescimbini, Federico Caricchi, Giorgio Lucchi
  • Publication number: 20050035676
    Abstract: Methods and apparatus are provided for an electric vehicle embodying an axial flux traction motor directly coupled to a wheel thereof. The traction motor comprises a stator having coils for producing a magnetic field, an annular rotor magnetically coupled to the stator and mechanically to an output shaft. Permanent magnets of alternating polarity are mounted on the annular rotor. Magnetic shunts bridge a portion of the stator slots above the coils. The magnets are arranged in groups with group-to-group spacing exceeding magnet-to-magnet spacing. Adjacent edges of the magnets diverge. The method comprises, looking up d- and q-axis currents to provide the requested torque and motor speed for the available DC voltage, combining at least one of the d- and q-axis currents with a field weakening correction term, converting the result from synchronous to stationary frame and operating an inverter therewith to provide current to the coils of the motor.
    Type: Application
    Filed: July 29, 2004
    Publication date: February 17, 2005
    Inventors: Khwaja Rahman, Silva Hiti, Nitinkumar Patel, Terence Ward, James Nagashima, Fabio Crescimbini, Federico Caricchi
  • Publication number: 20050029983
    Abstract: An induction machine includes a rotor having rotor flux and a rotor resistance. The induction machine outputs first and second reference current values. A control system includes a first controller that outputs first and second reference voltage values to the induction machine and that generates an estimated rotor flux magnitude value based on a rotor resistance parameter. A computation circuit receives the first and second reference current values from the induction machine and the first and second voltage reference values from the first controller and calculates an actual rotor flux magnitude. A rotor resistance adjustor that updates the rotor resistance parameter based on the actual and estimated rotor flux magnitudes.
    Type: Application
    Filed: August 6, 2003
    Publication date: February 10, 2005
    Inventors: Milan Mijalkovic, Aleksandar Stankovic, Silva Hiti, James Nagashima
  • Publication number: 20050024902
    Abstract: The present invention includes a method for thermal management in a voltage source inverter. The method includes sensing a low output frequency condition, determining a zero vector modulation responsive to the sensed low output frequency condition, and applying the determined zero vector modulation to reduce thermal stress in the voltage source inverter. The step of determining the zero vector modulation responsive to the sensed low output frequency condition includes mapping an output voltage requirement to a space vector structure and determining state switching space vectors based on the mapped output voltage requirement.
    Type: Application
    Filed: August 1, 2003
    Publication date: February 3, 2005
    Inventors: Silva Hiti, Constantin Stancu, Khwaja Rahman, Scott Downer, James Nagashima, Eric Ostrom
  • Patent number: 6381110
    Abstract: A method for detecting an isolation fault in a system comprising a source connected an inverter through a circuit interrupter, the inverter connected to windings of an electric motor for driving the electric motor, is presented. The method comprising operating the inverter (1) to yield a zero net current in the windings of the electric motor other than leakage current resulting from an isolation fault or (2) to apply a voltage to at least one of the windings of the electric motor for a period of time given an ohmic level of an isolation fault to be detected; and measuring a voltage in the system, wherein a voltage level measured during this operation of the inverter is indicative of the existence of an isolation fault. Thereafter, the circuit interrupter is actuated in response to the voltage level indicative of the existence of the isolation fault.
    Type: Grant
    Filed: March 6, 2000
    Date of Patent: April 30, 2002
    Assignee: General Motors Corporation
    Inventors: James Nagashima, James Souther, Scott D. Downer
  • Patent number: 6369319
    Abstract: A power electronics chassis (10) for electric vehicles and other applications that use liquid coolant to cool power electronic devices (20) contained within the chassis. The chassis (10) includes an electrically conductive housing (12) and an electrically non-conductive manifold (16) that permits coolant flow into and out of the housing. The housing (12) has at least one wall (34) that includes an outer surface (42) and a pair of recessed apertures (36,72), each of which provide access to an interior region (38) of the housing (12) via a passageway (40,74). The manifold (16) has an inlet (26) and an outlet (28), each of which has a connecting tube (54,80) that extends through one of the passageways (40,74). Each passageway (40,74) is defined by an axial wall (44,78) of the housing (12) that extends towards the interior region (38) from the outer surface (42) to its respective aperture.
    Type: Grant
    Filed: April 19, 2000
    Date of Patent: April 9, 2002
    Assignee: General Motors Corporation
    Inventors: James Nagashima, Terence G. Ward, Scott D. Downer
  • Patent number: 6356182
    Abstract: A power bus bar assembly comprising planar electromagnetic interference (EMI) inductors. An exemplary power bus bar assembly or planar inductor comprises upper and lower E-E magnetic cores, and upper and lower flat bus bars that are insulated from each other. The bus bars have a plurality of core cut-outs that allow the cores to pass through them. The core cut-outs form an electrical path through the E-E cores that forms a turn that provides a predetermined amount of inductance. The bus bars may be arranged to form turns in the same direction or opposing directions that provide for a common mode and differential mode inductors, respectively. Different core materials and stacking of multiple cores may be used to improve the frequency response of the inductor.
    Type: Grant
    Filed: September 20, 1999
    Date of Patent: March 12, 2002
    Assignee: General Motors Corporation
    Inventor: James Nagashima
  • Patent number: 6262896
    Abstract: An electric power system for an electric vehicle includes an electric drive motor, a high voltage bus for supplying operating power to energize the drive motor, and an inverter including power switching devices and having an inverter output. The inverter is coupled between the high voltage bus and the electric drive motor and a controller is coupled to the inverter and provides motor control signals and high frequency injection signals to the inverter. An auxiliary power unit is coupled to the inverter output and has a DC output for supplying DC operating power. The auxiliary power unit supplies DC power in response to the high frequency injection signals. The electric drive motor operates in response to the motor control signals and is substantially unaffected by the high frequency injection signals.
    Type: Grant
    Filed: June 19, 2000
    Date of Patent: July 17, 2001
    Assignee: General Motors Corporation
    Inventors: Constantin C. Stancu, Silva Hiti, James Nagashima