Patents by Inventor James M. Nagashima

James M. 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).

  • Patent number: 7061134
    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: Grant
    Filed: August 1, 2003
    Date of Patent: June 13, 2006
    Assignee: General Motors Corporation
    Inventors: Silva Hiti, Constantin C. Stancu, Khwaja Rahman, Scott D. Downer, James M. Nagashima, Eric R. Ostrom
  • Patent number: 7057371
    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: Grant
    Filed: April 19, 2004
    Date of Patent: June 6, 2006
    Assignee: General Motors Corporation
    Inventors: Brian Welchko, James M. Nagashima, Khwaja M. Rahman
  • Patent number: 7002318
    Abstract: A control system for a motor including a rotor comprises a sensorless sensor module that includes a saliency-based estimator module that generates a first rotor position signal based on saliency and a back electromotive force (emf) estimator module that generates a second rotor position signal based on back emf. A selector selects the first rotor position signal for rotor speeds below a first rotor speed and the second rotor position signal for rotor speeds above the first rotor speed. A rotor position sensor senses a position of the rotor and generates a third rotor position signal. A fault detection module senses faults in the rotor position sensor and outputs the third rotor position signal when a fault is not detected and one of the first and second rotor position signals when the fault is detected. An indirect field oriented control (IFOC) system controls the motor based on a selected one of the first, second and third rotor position signals.
    Type: Grant
    Filed: September 23, 2004
    Date of Patent: February 21, 2006
    Assignee: General Motors Corporation
    Inventors: Steven E. Schulz, Sean E Gleason, Nitinkumar R. Patel, James M. Nagashima, Yu-Seok Jeong, Seung Ki Sul, Michael Milani
  • Patent number: 6989641
    Abstract: A method for controlling an electric machine having current sensors for less than every phase of the electric machine includes operating a processor to perform a test to preliminarily determine whether a fault exists in one or more of the current sensors and a test to finally determine that the fault exists in the one or more current sensors. The method further includes operating the processor to utilize a state observer of the electric machine to estimate states of the electric machine, wherein the state observer is provided state input measurements from each non-faulty current sensor, if any. Measurements from the current sensor or sensors determined to be faulty are disregarded. The processor controls the electric machine utilizing results from the state observer.
    Type: Grant
    Filed: June 2, 2003
    Date of Patent: January 24, 2006
    Assignee: General Motors Corporation
    Inventors: Steven E. Schulz, Nitinkumar R. Patel, James M. Nagashima, Yu-Seok Jeong, Seung Ki Sul
  • Patent number: 6979968
    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: Grant
    Filed: October 1, 2003
    Date of Patent: December 27, 2005
    Assignee: General Motors Corporation
    Inventors: James M. Nagashima, Thomas P. O'Meara, Nitinkumar R. Patel, Steven E. Schulz
  • Patent number: 6924617
    Abstract: A control system for an electric motor having a stator and rotor including an inverter for providing power to the electric motor, a controller for controlling the inverter, a low speed control block to estimate the rotor angular position using stator current components operating in the controller, a high speed control block to estimate the rotor angular position using stator current components and stator flux position operating in the controller, a transition switch in the controller to vary operation between the low speed control block and the high speed control block, and where the inverter is controlled by six step operation.
    Type: Grant
    Filed: June 23, 2003
    Date of Patent: August 2, 2005
    Assignee: General Motors Corporation
    Inventors: Steven E. Schulz, Nitinkumar R. Patel, James M. Nagashima, Seung Ki Sul, Bon-Ho Bae
  • Patent number: 6894454
    Abstract: A control system for an electric motor including an inverter for providing power to the electric motor, a controller for controlling the inverter, a first motor speed control block in the controller injecting a high frequency signal into the electric motor to determine the speed and position of the electric motor, a second motor speed control block in the controller detecting the back electromotive force to determine the speed and position of the electric motor, and a transition control block in said controller to vary operation between the first motor speed control block and the second motor speed control block.
    Type: Grant
    Filed: October 10, 2002
    Date of Patent: May 17, 2005
    Assignee: General Motors Corporation
    Inventors: Nitinkumar R. Patel, Steven E. Schulz, James M. Nagashima, Seung Ki Sul, Yo-Chan Son, Bon-Ho Bae
  • Patent number: 6870348
    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: Grant
    Filed: August 6, 2003
    Date of Patent: March 22, 2005
    Assignee: General Motors Corporation
    Inventors: Milan S. Mijalkovic, Aleksandar M. Stankovic, Silva Hiti, James M. Nagashima
  • Publication number: 20040257028
    Abstract: A control system for an electric motor having a stator and rotor including an inverter for providing power to the electric motor, a controller for controlling the inverter, a low speed control block to estimate the rotor angular position using stator current components operating in the controller, a high speed control block to estimate the rotor angular position using stator current components and stator flux position operating in the controller, a transition switch in the controller to vary operation between the low speed control block and the high speed control block, and where the inverter is controlled by six step operation.
    Type: Application
    Filed: June 23, 2003
    Publication date: December 23, 2004
    Inventors: Steven E. Schulz, Nitinkumar R. Patel, James M. Nagashima, Seung Ki Sul, Bon-Ho Bae
  • Patent number: 6831442
    Abstract: A method for providing additional dc inputs or outputs (49, 59) from a dc-to-ac inverter (10) for controlling motor loads (60) comprises deriving zero-sequence components (Vao, Vbo, and Vco) from the inverter (10) through additional circuit branches with power switching devices (23, 44, 46), transforming the voltage between a high voltage and a low voltage using a transformer or motor (42, 50), converting the low voltage between ac and dc using a rectifier (41, 51) or an H-bridge (61), and providing at least one low voltage dc input or output (49, 59). The transformation of the ac voltage may be either single phase or three phase. Where less than a 100% duty cycle is acceptable, a two-phase modulation of the switching signals controlling the inverter (10) reduces switching losses in the inverter (10). A plurality of circuits for carrying out the invention are also disclosed.
    Type: Grant
    Filed: July 3, 2002
    Date of Patent: December 14, 2004
    Assignees: General Motors Corporation, UT-Battelle, LLC
    Inventors: John S. Hsu, Gui-Jia Su, Donald J. Adams, James M. Nagashima, Constantin Stancu, Douglas S. Carlson, Gregory S. Smith
  • Publication number: 20040239272
    Abstract: A method for controlling an electric machine having current sensors for less than every phase of the electric machine includes operating a processor to perform a test to preliminarily determine whether a fault exists in one or more of the current sensors and a test to finally determine that the fault exists in the one or more current sensors. The method further includes operating the processor to utilize a state observer of the electric machine to estimate states of the electric machine, wherein the state observer is provided state input measurements from each non-faulty current sensor, if any. Measurements from the current sensor or sensors determined to be faulty are disregarded. The processor controls the electric machine utilizing results from the state observer.
    Type: Application
    Filed: June 2, 2003
    Publication date: December 2, 2004
    Inventors: Steven E. Schulz, Nitinkumar R. Patel, James M. Nagashima, Yu-Seok Jeong, Seung-Ki Sul
  • Patent number: 6768932
    Abstract: A wheel motor traction assembly configured for use on a light duty vehicle adaptable for electric traction. The wheel motor traction assembly includes a wheel, a brake disc operatively connected to the wheel, a motor operatively connected to the wheel and a motor housing operatively connected to the motor. The motor housing has structural connectors for steering and suspension systems on a vehicle chassis and has a brake caliper operatively connected thereto. A parking brake caliper may also be connected to the motor housing for connection to a parking brake cable on the chassis. The motor housing is configured to bear vehicle chassis loads as the motor housing structurally interconnects the wheel to the chassis through the structural connectors.
    Type: Grant
    Filed: December 4, 2002
    Date of Patent: July 27, 2004
    Assignee: General Motors Corporation
    Inventors: George M. Claypole, Bruce Edward Zemke, Cheuk S. Ng, Douglas Lee Wickham, Milos Stakich, Chris J. Karras, James M. Nagashima, Khwaja M. Rahman, Terence G. Ward
  • Publication number: 20040084229
    Abstract: The preferred embodiments of the present invention utilize the internal combustion engine of a hybrid vehicle, coupled with an energy storage device and series of inverters to provide electrical power generation capability for an electric power take-off (EPTO) system. Additional embodiments of the present invention utilize an existing on-board AC induction motor to provide filtering capability for the generated AC power.
    Type: Application
    Filed: October 31, 2002
    Publication date: May 6, 2004
    Inventors: Constantin Stancu, James M. Nagashima, Simon H. McCullough
  • Publication number: 20040070362
    Abstract: A control system for an electric motor including an inverter for providing power to the electric motor, a controller for controlling the inverter, a first motor speed control block in the controller injecting a high frequency signal into the electric motor to determine the speed and position of the electric motor, a second motor speed control block in the controller detecting the back electromotive force to determine the speed and position of the electric motor, and a transition control block in said controller to vary operation between the first motor speed control block and the second motor speed control block.
    Type: Application
    Filed: October 10, 2002
    Publication date: April 15, 2004
    Inventors: Nitinkumar R. Patel, Steven E. Schulz, James M. Nagashima, Seung Ki Sul, Yo-Chan Son, Bon-Ho Bae
  • Patent number: 6707222
    Abstract: A method for making a motor and auxiliary devices with a unified stator body comprises providing a piece of material (10) having an area larger than a cross section of the stator (11), removing material from the piece of material (10) to form a pattern for a cross section of a core (11) for the stator, and removing material from the piece of material (10) outside the cross section of the core of the stator (11) to allow positioning of cores (22, 23, 24) for supporting windings (25, 26, 27) of least one additional electromagnetic device, such as a transformer (62) in a dc-to-dc converter (61, 62) that provides a low. voltage dc output. An article of manufacture made according to the invention is also disclosed and apparatus made with the method and article of manufacture are also disclosed.
    Type: Grant
    Filed: July 3, 2002
    Date of Patent: March 16, 2004
    Assignee: UT-Battelle, LLC
    Inventors: John S. Hsu, Gui-Jia Su, Donald J. Adams, James M. Nagashima, Constantin Stancu, Douglas S. Carlson, Gregory S. Smith
  • Publication number: 20040004852
    Abstract: A method for providing additional dc inputs or outputs (49, 59) from a dc-to-ac inverter (10) for controlling motor loads (60) comprises deriving zero-sequence components (Vao, Vbo, and Vco) from the inverter (10) through additional circuit branches with power switching devices (23, 44, 46), transforming the voltage between a high voltage and a low voltage using a transformer or motor (42, 50), converting the low voltage between ac and dc using a rectifier (41, 51) or an H-bridge (61), and providing at least one low voltage dc input or output (49, 59). The transformation of the ac voltage may be either single phase or three phase. Where less than a 100% duty cycle is acceptable, a two-phase modulation of the switching signals controlling the inverter (10) reduces switching losses in the inverter (10). A plurality of circuits for carrying out the invention are also disclosed.
    Type: Application
    Filed: July 3, 2002
    Publication date: January 8, 2004
    Inventors: John S. Hsu, Gui-Jia Su, Donald J. Adams, James M. Nagashima, Constantin Stancu, Douglas S. Carlson, Gregory S. Smith
  • Publication number: 20040004410
    Abstract: A method for making a motor and auxiliary devices with a unified stator body comprises providing a piece of material (10) having an area larger than a cross section of the stator (11), removing material from the piece of material (10) to form a pattern for a cross section of a core (11) for the stator, and removing material from the piece of material (10) outside the cross section of the core of the stator (11) to allow positioning of cores (22, 23, 24) for supporting windings (25, 26, 27) of least one additional electromagnetic device, such as a transformer (62) in a dc-to-dc converter (61, 62) that provides a low voltage dc output. An article of manufacture made according to the invention is also disclosed and apparatus made with the method and article of manufacture are also disclosed.
    Type: Application
    Filed: July 3, 2002
    Publication date: January 8, 2004
    Inventors: John S. Hsu, Gui-Jia Su, Donald J. Adams, James M. Nagashima, Constantin Stancu, Douglas S. Carlson, Gregory S. Smith
  • Patent number: 6617820
    Abstract: A method of generating low voltage auxiliary power forms for electric or hybrid vehicle use by tapping power from the traction motor primary winding with a secondary winding and rectifier.
    Type: Grant
    Filed: September 7, 2001
    Date of Patent: September 9, 2003
    Assignee: General Motors Corporation
    Inventors: Douglas S. Carlson, Constantin C. Stancu, James M. Nagashima, Silva Hiti, Khwaja M. Rahman
  • Publication number: 20030159866
    Abstract: A wheel motor traction assembly configured for use on a light duty vehicle adaptable for electric traction. The wheel motor traction assembly includes a wheel, a brake disc operatively connected to the wheel, a motor operatively connected to the wheel and a motor housing operatively connected to the motor. The motor housing has structural connectors for steering and suspension systems on a vehicle chassis and has a brake caliper operatively connected thereto. A parking brake caliper may also be connected to the motor housing for connection to a parking brake cable on the chassis. The motor housing is configured to bear vehicle chassis loads as the motor housing structurally interconnects the wheel to the chassis through the structural connectors.
    Type: Application
    Filed: December 4, 2002
    Publication date: August 28, 2003
    Inventors: George M. Claypole, Bruce Edward Zemke, Cheuk S. Ng, Douglas Lee Wickham, Milos Stakich, Chris J. Karras, James M. Nagashima, Khwaja M. Rahman, Terence G. Ward
  • Patent number: 6608396
    Abstract: A power control system for an electric traction motor in a vehicle comprising at least one inverter for providing conditioned electrical power to the electric traction motor, a plurality of power stages for providing DC power to the at least one inverter, each stage including a battery and boost/buck DC—DC converter, the power stages wired in parallel, and where the power stages are controlled to maintain an output voltage to the at least one inverter.
    Type: Grant
    Filed: December 6, 2001
    Date of Patent: August 19, 2003
    Assignee: General Motors Corporation
    Inventors: Scott D. Downer, James F. Lazar, James M. Nagashima