METHOD AND SYSTEM FOR SENSORLESS CONTROL OF AN ELECTRIC MOTOR

• US 20090140676A1
• Filed: 11/29/2007
• Published: 06/04/2009
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Patel, Nitinkumar R., Son, Yo Chan, Schulz, Steven E.
• Granted Patent: US 8,340,848 B2
• Time in Patent Office: Days
• US Class Current: 318/400.40
• CPC Class Codes: H02P 21/13 Observer control, e.g. using Luenberger observers or Kalman filters
• CPC Class Codes: H02P 21/141 Flux estimation
• CPC Class Codes: H02P 21/24 Vector control not involving the use of rotor position or rotor speed sensors

Abstract

Methods and systems for controlling an electric motor are provided. A signal comprising at least first and second cycles is provided to the electric motor. A first flux value for the electric motor associated with the first cycle of the signal is calculated. A second flux value for the electric motor associated with the second cycle of the signal is calculated based on the first flux value.

Claims

1. A method for controlling an electric motor comprising:

providing a signal comprising at least first and second cycles to the electric motor;

calculating a first flux value for the electric motor associated with the first cycle of the signal; and

calculating a second flux value based on the first flux value for the electric motor associated with the second cycle of the signal.

2. The method of claim 1, further comprising measuring a current flowing through the electric motor during the second cycle and wherein the calculating of the second flux value is further based on the measured current flowing through the motor during the second cycle.

3. The method of claim 2, wherein the first cycle occurs before the second cycle.

4. The method of claim 3, wherein the first and second flux values each comprise a flux linkage, a back electromotive force (BEMF) generated by the motor, or a combination of the flux linkage and the BEMF.

5. The method of claim 4, wherein the signal comprises a third cycle.

6. The method of claim 5, further comprising measuring a current flowing through the electric motor during the third cycle and wherein the calculating of the second flux value is further based on the measured current flowing through the motor during the third cycle.

7. The method of claim 6, wherein the third cycle occurs before the first cycle.

8. The method of claim 7, wherein the calculating of the first flux value comprises measuring a current flowing through the electric motor during the first cycle.

9. The method of claim 8, wherein the calculating of the second flux value comprises determining a voltage associated with the measured current flowing through the electric motor during the third cycle.

10. The method of claim 9, wherein the first cycle of the signal occurs before the second cycle of the signal and the third cycle of the signal occurs before the first cycle of the signal.

11. A method for controlling an automotive electric motor having a winding comprising:

providing a signal comprising first and second cycles to the electric motor;

determining a winding flux error based on a measured winding flux and an estimated winding flux; and

calculating a first flux value of the electric motor based on the winding flux error, the first flux value comprising a flux linkage, a back electromotive force (BEMF) generated by the motor, or a combination of the flux linkage and the BEMF.

12. The method of claim 11, wherein the first flux value is associated with the first cycle of the signal and further comprising calculating a second flux value for the electric motor associated with the second cycle of the signal based on the first flux value, the second flux value comprising the flux linkage, the BEMF generated by the motor, or a combination of the flux linkage and the BEMF.

13. The method of claim 12, wherein the signal further comprises a third cycle, further comprising measuring a current flowing through the electric motor during the third cycle, and wherein the calculating the second flux value is further based on the measured current flowing through the electric motor during the third cycle.

14. The method of claim 13, wherein the first cycle of the PWM signal occurs before the second cycle of the PWM signal and the third cycle of the PWM signal occurs before the first cycle of the PWM signal.

15. The method of claim 14, wherein the calculating of the first flux value comprises measuring a current flowing through the electric motor during the first cycle of the PWM signal and the calculating of the second flux value comprises determining a voltage associated with the measured current flowing through the electric motor during the third cycle of the PWM cycle

16. An automotive drive system comprising:

an electric motor;

a direct current (DC) power supply coupled to the electric motor;

a power inverter coupled to the electric motor and the DC power supply to receive DC power from the DC power supply and provide alternating current (AC) power to the electric motor; and

a processor in operable communication with the electric motor, the DC power supply, and the power inverter, the processor being configured to;

provide a signal comprising at least first and second cycles to the electric motor;

calculate a first flux value for the electric motor associated with the first cycle of the signal; and

calculate a second flux value for the electric motor associated with the second cycle of the signal based on the first flux value.

17. The automotive drive system of claim 16, wherein the first and second flux values each comprise a flux linkage, a back electromotive force (BEMF) generated by the motor, or a combination of the flux linkage and the BEMF.

18. The automotive drive system of claim 17, wherein the signal comprises a third cycle and the processor is further configured to measure a current flowing through the electric motor during the third cycle and wherein the calculating of the second flux value is further based on the measured current flowing through the electric motor during the third cycle.

19. The automotive drive system of claim 18, wherein the processor is further configured to measure a current flowing through the electric motor during the second cycle and wherein the calculating of the second flux value is further based on the measured current flowing through the motor during the second cycle.

20. The automotive drive system of claim 19, wherein the signal is a pulse width modulation (PWM) signal and wherein the first cycle of the PWM signal occurs before the second cycle of the PWM signal and the third cycle of the PWM signal occurs before the first cycle of the PWM signal.