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).
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Patent number: 7061134Abstract: 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: GrantFiled: August 1, 2003Date of Patent: June 13, 2006Assignee: General Motors CorporationInventors: Silva Hiti, Constantin C. Stancu, Khwaja Rahman, Scott D. Downer, James M. Nagashima, Eric R. Ostrom
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Patent number: 7057371Abstract: 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: GrantFiled: April 19, 2004Date of Patent: June 6, 2006Assignee: General Motors CorporationInventors: Brian Welchko, James M. Nagashima, Khwaja M. Rahman
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Patent number: 7002318Abstract: 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: GrantFiled: September 23, 2004Date of Patent: February 21, 2006Assignee: General Motors CorporationInventors: Steven E. Schulz, Sean E Gleason, Nitinkumar R. Patel, James M. Nagashima, Yu-Seok Jeong, Seung Ki Sul, Michael Milani
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Patent number: 6989641Abstract: 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: GrantFiled: June 2, 2003Date of Patent: January 24, 2006Assignee: General Motors CorporationInventors: Steven E. Schulz, Nitinkumar R. Patel, James M. Nagashima, Yu-Seok Jeong, Seung Ki Sul
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Patent number: 6979968Abstract: 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: GrantFiled: October 1, 2003Date of Patent: December 27, 2005Assignee: General Motors CorporationInventors: James M. Nagashima, Thomas P. O'Meara, Nitinkumar R. Patel, Steven E. Schulz
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Patent number: 6924617Abstract: 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: GrantFiled: June 23, 2003Date of Patent: August 2, 2005Assignee: General Motors CorporationInventors: Steven E. Schulz, Nitinkumar R. Patel, James M. Nagashima, Seung Ki Sul, Bon-Ho Bae
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Patent number: 6894454Abstract: 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: GrantFiled: October 10, 2002Date of Patent: May 17, 2005Assignee: General Motors CorporationInventors: Nitinkumar R. Patel, Steven E. Schulz, James M. Nagashima, Seung Ki Sul, Yo-Chan Son, Bon-Ho Bae
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Patent number: 6870348Abstract: 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: GrantFiled: August 6, 2003Date of Patent: March 22, 2005Assignee: General Motors CorporationInventors: Milan S. Mijalkovic, Aleksandar M. Stankovic, Silva Hiti, James M. Nagashima
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Publication number: 20040257028Abstract: 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: ApplicationFiled: June 23, 2003Publication date: December 23, 2004Inventors: Steven E. Schulz, Nitinkumar R. Patel, James M. Nagashima, Seung Ki Sul, Bon-Ho Bae
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Patent number: 6831442Abstract: 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: GrantFiled: July 3, 2002Date of Patent: December 14, 2004Assignees: General Motors Corporation, UT-Battelle, LLCInventors: John S. Hsu, Gui-Jia Su, Donald J. Adams, James M. Nagashima, Constantin Stancu, Douglas S. Carlson, Gregory S. Smith
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Publication number: 20040239272Abstract: 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: ApplicationFiled: June 2, 2003Publication date: December 2, 2004Inventors: Steven E. Schulz, Nitinkumar R. Patel, James M. Nagashima, Yu-Seok Jeong, Seung-Ki Sul
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Patent number: 6768932Abstract: 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: GrantFiled: December 4, 2002Date of Patent: July 27, 2004Assignee: General Motors CorporationInventors: 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
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Publication number: 20040084229Abstract: 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: ApplicationFiled: October 31, 2002Publication date: May 6, 2004Inventors: Constantin Stancu, James M. Nagashima, Simon H. McCullough
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Publication number: 20040070362Abstract: 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: ApplicationFiled: October 10, 2002Publication date: April 15, 2004Inventors: Nitinkumar R. Patel, Steven E. Schulz, James M. Nagashima, Seung Ki Sul, Yo-Chan Son, Bon-Ho Bae
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Patent number: 6707222Abstract: 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: GrantFiled: July 3, 2002Date of Patent: March 16, 2004Assignee: UT-Battelle, LLCInventors: John S. Hsu, Gui-Jia Su, Donald J. Adams, James M. Nagashima, Constantin Stancu, Douglas S. Carlson, Gregory S. Smith
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Publication number: 20040004852Abstract: 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: ApplicationFiled: July 3, 2002Publication date: January 8, 2004Inventors: John S. Hsu, Gui-Jia Su, Donald J. Adams, James M. Nagashima, Constantin Stancu, Douglas S. Carlson, Gregory S. Smith
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Publication number: 20040004410Abstract: 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: ApplicationFiled: July 3, 2002Publication date: January 8, 2004Inventors: John S. Hsu, Gui-Jia Su, Donald J. Adams, James M. Nagashima, Constantin Stancu, Douglas S. Carlson, Gregory S. Smith
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Patent number: 6617820Abstract: 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: GrantFiled: September 7, 2001Date of Patent: September 9, 2003Assignee: General Motors CorporationInventors: Douglas S. Carlson, Constantin C. Stancu, James M. Nagashima, Silva Hiti, Khwaja M. Rahman
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Publication number: 20030159866Abstract: 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: ApplicationFiled: December 4, 2002Publication date: August 28, 2003Inventors: 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
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Patent number: 6608396Abstract: 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: GrantFiled: December 6, 2001Date of Patent: August 19, 2003Assignee: General Motors CorporationInventors: Scott D. Downer, James F. Lazar, James M. Nagashima