Nitinkumar Kanjibhai Patel

US Patent:

6760669, Jul 6, 2004

Filed:

Feb 20, 2001

Appl. No.:

09/789217

Inventors:

Nitinkumar R. Patel - Buena Park CA
Thomas P. OMeara - Redondo Beach CA

Assignee:

General Motors Corporation - Detroit MI

International Classification:

G01R 1500

US Classification:

702 57

Abstract:

A method of reducing loss in an interior permanent magnet drive system is provided. A current input DC link power value is calculated. The current input DC link power value is then compared with a previous input DC link power value. A change in input DC link power value is determined from this comparison. A flux decrement value is calculated. The flux decrement value is based on the change in input DC link power value. A stator current value is generated. The stator current value is based on the flux decrement value. Finally, the stator flux current is reduced, based on the stator current value.

US Patent:

6762573, Jul 13, 2004

Filed:

Feb 26, 2002

Appl. No.:

10/085595

Inventors:

Nitinkumar Ratilal Patel - Buena Park CA

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 118

US Classification:

318254, 318430, 318432, 318434, 318700, 318727, 318138

Abstract:

A rotor position estimator for a permanent magnet motor with a stator and a rotor includes a sensing circuit that generates d-axis and q-axis negative sequence stationary current (NSSC) signals. A signal conditioning circuit combines the d-axis and q-axis NSSC signals with first and second positive feedback signals that are based on a rotor position estimate signal. A regulator is coupled to an output of the signal conditioning circuit. A mechanical system simulator that is coupled to the regulator and a demand torque signal generates the rotor position estimate signal. The signal conditioning circuit includes a second harmonic amplifying circuit that receives the rotor position estimate signal and outputs the first feedback signal to a first multiplier. The signal conditioning circuit includes an inverse saliency model receives the rotor position estimate signal and outputs the second feedback signal to a second multiplier.

US Patent:

6841969, Jan 11, 2005

Filed:

Sep 24, 2003

Appl. No.:

10/669918

Inventors:

Steven E. Schulz - Torrance CA, US
Nitinkumar R. Patel - Cypress CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 618

US Classification:

318807, 318254, 318138, 318439, 318610, 318799

Abstract:

A control system includes a field oriented controller that receives a torque command and that generates phase voltages for an electric machine. A first transformation module receives stator terminal currents and generates d-axis and q-axis stationary frame currents. An open loop flux observer receives d-axis and q-axis stationary frame voltage commands and the d and q-axis stationary frame currents. The open loop flux observer includes a vector cross product calculator that generates an error signal that is proportional to an angular difference between an estimated stator flux and a computed stator flux and a proportional integral controller that generates an estimated rotor angular position based on the error signal. A second transformation module receives the d-axis and q-axis stationary frame currents and the estimated rotor angular position and generates d-axis and q-axis synchronous reference frame feedback currents that are output to the field oriented controller.

US Patent:

6894454, May 17, 2005

Filed:

Oct 10, 2002

Appl. No.:

10/268503

Inventors:

Nitinkumar R. Patel - Cypress CA, US
Steven E. Schulz - Torrance CA, US
James M. Nagashima - Cerritos CA, US
Seung Ki Sul - Seoul, KR
Yo-Chan Son - Seoul, KR
Bon-Ho Bae - Seoul, KR

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P001/46

US Classification:

318700, 318701, 318254, 318138, 318439

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.

US Patent:

6924617, Aug 2, 2005

Filed:

Jun 23, 2003

Appl. No.:

10/601726

Inventors:

Steven E. Schulz - Torrance CA, US
Nitinkumar R. Patel - Cypress CA, US
James M. Nagashima - Cerritos CA, US
Seung Ki Sul - Seoul, KR
Bon-Ho Bae - Seoul, KR

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P001/46
H02P001/18
G05B011/42

US Classification:

318701, 318719, 318721, 318801, 318254, 318138, 318439, 318610

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.

US Patent:

6979968, Dec 27, 2005

Filed:

Oct 1, 2003

Appl. No.:

10/676529

Inventors:

James M. Nagashima - Cerritos CA, US
Thomas P. O'Meara - Redondo Beach CA, US
Nitinkumar R. Patel - Cypress CA, US
Steven E. Schulz - Torrance CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P003/00

US Classification:

318268, 318599, 318461, 700 19

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. In one embodiment, the processor control algorithm modifies the inverter switching frequency based on the modified inverter switching frequency value.

US Patent:

6989641, Jan 24, 2006

Filed:

Jun 2, 2003

Appl. No.:

10/452817

Inventors:

Steven E. Schulz - Torrance CA, US
Nitinkumar R. Patel - Cypress CA, US
James M. Nagashima - Cerritos CA, US
Yu-Seok Jeong - Seoul, KR
Seung Ki Sul - Seoul, KR

Assignee:

General Motors Corporation - Detroit MI

International Classification:

B60L 3/00

US Classification:

318139, 318700, 318474, 318490

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.

US Patent:

7002318, Feb 21, 2006

Filed:

Sep 23, 2004

Appl. No.:

10/948630

Inventors:

Steven E. Schulz - Torrance CA, US
Sean E Gleason - West Bloomfield MI, US
Nitinkumar R. Patel - Cypress CA, US
James M. Nagashima - Cerritos CA, US
Yu-Seok Jeong - Seoul, KR
Seung Ki Sul - Seoul, KR
Michael Milani - San Pedro CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 7/50
B80L 3/00

US Classification:

318782, 318437, 318474, 318490

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.