Nitinkumar S 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:

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:

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:

7015667, Mar 21, 2006

Filed:

Mar 24, 2004

Appl. No.:

10/808082

Inventors:

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

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 7/00

US Classification:

318432, 318433

Abstract:

A control system and method for an electric machine includes a first calculation module that receives a modified torque command and a calculated stator flux command and that generates first and second current commands and first and second voltage commands. A voltage magnitude calculation module generates a voltage magnitude based the first and second voltage commands. A reference voltage calculator module generates a reference voltage based on a DC link voltage, an angular stator velocity and the first and second current commands. A flux weakening module generates the calculated flux command based on the angular stator velocity, the reference voltage and the voltage magnitude.

US Patent:

7023168, Apr 4, 2006

Filed:

Sep 13, 2004

Appl. No.:

10/939553

Inventors:

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

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 3/18
H02P 5/04
H02P 5/28

US Classification:

318757, 318700, 318701, 318721, 318722, 318810

Abstract:

A control system for an electric machine includes a flux weakening module, which includes a voltage magnitude calculator that receives d-axis and q-axis command voltages and that generates a voltage magnitude. An error circuit compares the voltage magnitude to a reference voltage and generates an error signal. A controller receives the error signal and generates a feedback flux correction signal. A limiter limits the feedback flux correction signal to a predetermined flux value and generates a limited feedback flux correction signal. A feedforward stator flux generating circuit generates a feedforward stator flux signal. A summing circuit sums the feedforward stator flux signal and the limited feedback flux correction signal to generate a final stator flux command.

US Patent:

7042186, May 9, 2006

Filed:

Nov 24, 2003

Appl. No.:

10/720626

Inventors:

Constantin C. Stancu - Anaheim CA, US
Silva Hiti - Redondo Beach CA, US
Steven E. Schulz - Torrance CA, US
Nitinkumar R. Patel - Cypress CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

G05B 11/36

US Classification:

318609, 318610, 318621, 318799, 318809

Abstract:

A method for decoupling a harmonic signal from an input signal wherein the harmonic signal is harmonic relative to a signal other than the input signal. An angular position of the other signal is multiplied by a value representing the harmonic to obtain an angular position multiple. A harmonic decoupling block uses the angular position multiple to obtain correction signals representing the harmonic signal, and subtracts the correction signals from the input current to decouple the harmonic signal from the input signal. This method is useful for decoupling unwanted harmonics from currents into which high-frequency signals have been injected for control of electric motors.

US Patent:

7088077, Aug 8, 2006

Filed:

Nov 9, 2004

Appl. No.:

10/984178

Inventors:

James M. Nagashima - Cerritos CA, US
Khwaja M. Rahman - Torrance CA, US
Nitinkumar R. Patel - Cypress CA, US
Steven E. Schulz - Torrance CA, US
Terence G. Ward - Redondo Beach CA, US
Stanley K. Fujii - Torrance CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 9/00
H02P 7/00

US Classification:

322 37, 322 20, 318432

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.