Steven C Schulz

US Patent:

6359413, Mar 19, 2002

Filed:

Apr 28, 2000

Appl. No.:

09/560339

Inventors:

Steven E. Schulz - Redondo Beach CA
Khwaja M. Rahman - Torrance CA

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 700

US Classification:

318701, 318254, 318439, 318801

Abstract:

A current control system for a switched reluctance motor that eliminates the effects of back EMF produced by such motor on the current control loop. The control system includes a current regulator that receives a current reference signal indicative of the desired output of the motor and a motor current signal indicative of the current in at least one phase winding of the motor. The regulator produces an output signal in response to the difference between the current reference signal and the motor current signal. The output of the regulator is a duty cycle command. A back EMF decoupler provides a back EMF signal indicative of the back EMF created by the motor and adds the back EMF signal to the current regulator output signal to provide a back EMF decoupled duty cycle command signal. An inverter circuit switches on and off the voltage to at least one phase winding of the motor in accordance with the back EMF decoupled duty cycle command signal to control the motor current and operate the motor.

US Patent:

6528964, Mar 4, 2003

Filed:

Mar 12, 2001

Appl. No.:

09/804557

Inventors:

Steven E. Schulz - Redondo Beach CA
Khwaja M. Rahman - Torrance CA

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02D 736

US Classification:

318701, 318138, 318254, 318432, 318434, 318720, 318721, 318722, 318724

Abstract:

An inverter for use in a switched reluctance (SR) motor drive is provided. The inverter comprises a first and second transistor for selectively providing current to an SR motor winding. A resonant-type snubber circuit is connected to the transistors to reduce turn-off loss. The snubber circuit includes a pair of diodes, a capacitor, and an inductor. The snubber circuit is reset during switch-on time of the transistors. At transistor turn-off time, the snubber circuit uses the capacitor to effectively limit the rate of change of voltage across the transistors. This allows the transistors to turn off with lower losses, and can also reduce the acoustical noise generated by the motor drive.

US Patent:

6646407, Nov 11, 2003

Filed:

Jun 8, 2001

Appl. No.:

09/877634

Inventors:

Khwaja M. Rahman - Torrance CA
Steven E. Schulz - Redondo Beach CA

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 705

US Classification:

318701, 318254, 318162

Abstract:

A controller for use in a switched reluctance (SR) motor drive is provided. The controller includes a DCâDC converter coupled to an inverter. The DCâDC converter can be a buck converter, a boost converter, or a buck-boost converter. The control parameters to the DCâDC converter can be optimal. In addition, the bus voltage of the motor drive can be reduced to a level such that the motor operates in single pulse mode. A capacitor can be connected in parallel across the outputs of the DCâDC converter supplying the inverter. Using the DCâDC converter to indirectly profile the phase current can reduce motor torque ripple.

US Patent:

6763622, Jul 20, 2004

Filed:

Oct 10, 2002

Appl. No.:

10/268507

Inventors:

Steven E. Schulz - Redondo Beach CA
Nitinkumar R. Patel - Cypress CA

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 146

US Classification:

38700, 318801, 318606, 318802, 318807, 318503

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, where the first motor speed control block includes a tuned moving average filter to determine the magnitude of high frequency current in the electric motor.

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:

6972534, Dec 6, 2005

Filed:

Sep 3, 2004

Appl. No.:

10/933679

Inventors:

Steven E. Schulz - Torrance CA, US
Daniel L. Kowalewski - Redondo Beach CA, US

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02K023/00
H02P005/06
G05B005/165

US Classification:

318254, 318608, 388811, 388812, 388813, 388814, 388815, 363 41

Abstract:

A control system for an electric machine having a rotor position sensor that generates a rotor position signal, a velocity module that generates an electric angular velocity value based on the rotor position signal, a random pulse width modulation module that generates a switching period and a delay for a current cycle, and a phase angle compensation module that sums a sample rate, one half of the switching period, and the delay of a previous cycle and that outputs a delay time. The phase angle compensation module further multiplies the delay time and the electric angular velocity value and generates a compensating angle.