ABSOLUTE POSITION SENSOR FOR FIELD-ORIENTED CONTROL OF AN INDUCTION MOTOR

• US 20090039825A1
• Filed: 06/11/2008
• Published: 02/12/2009
• Est. Priority Date: 08/06/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: STANCU, Constantin C., SAVAGIAN, Peter J., LABA, Matthew D., HATCH, Erik, DAWSEY, Robert T., HITI, Silva
• Granted Patent: US 8,390,240 B2
• Time in Patent Office: Days
• US Class Current: 318/799
• CPC Class Codes: B60L 15/025 using field orientation; Vector control; Direct Torque Control [DTC]
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: H02P 21/14 Estimation or adaptation of machine parameters, e.g. flux, current or voltage
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Systems and methods are provided for an automotive drive system using an absolute position sensor for field-oriented control of an induction motor. An automotive drive system comprises an induction motor having a rotor, and a position sensor coupled to the induction motor. The position sensor is configured to sense an absolute angular position of the rotor. A processor may be coupled to the position sensor and configured to determine a relative angular position of the rotor based on a difference between the absolute angular position and an initial angular position obtained when the induction motor is started. A controller may be coupled to the induction motor and the processor and configured to provide field-oriented control of the induction motor based on the relative angular position of the rotor.

Claims

1. An automotive drive system comprising:

an induction motor having a rotor; and

a position sensor coupled to the induction motor, wherein the position sensor is configured to sense an absolute angular position of the rotor.

2. The automotive drive system of claim 1, further comprising a processor coupled to the position sensor, the processor being configured to determine a relative angular position of the rotor based on a difference between the absolute angular position and an initial angular position, wherein the initial angular position is obtained when the induction motor is started.

3. The automotive drive system of claim 2, further comprising a controller coupled to the induction motor and the processor, the controller being configured to provide field-oriented control of the induction motor based on the relative angular position of the rotor.

4. The automotive drive system of claim 3, wherein the controller includes a speed observer configured to determine a speed of the rotor based on the relative angular position.

5. The automotive drive system of claim 4, wherein the controller is configured to determine a magnetizing current command based on the speed of the rotor.

6. The automotive drive system of claim 2, wherein the processor is configured to determine the relative angular position of the rotor by:

storing the initial angular position of the rotor; and

subtracting the initial angular position from a subsequent angular position of the rotor, wherein subtracting the initial angular position from the subsequent angular position results in the relative angular position.

7. The automotive drive system of claim 1, wherein the position sensor is a resolver.

8. The automotive drive system of claim 7, further comprising a resolver-to-digital converter coupled to the resolver, the resolver-to-digital converter being configured to determine a relative angular position of the rotor based on the absolute angular position.

9. The automotive drive system of claim 7, wherein the resolver is a two-pole resolver.

10. The automotive drive system of claim 7, wherein the resolver is integral with the induction motor.

11. A drive system for use in a vehicle, the drive system comprising:

an induction motor having a rotor; and

a position sensor integrated with the induction motor, the position sensor being configured to sense an absolute angular position of the rotor.

12. The drive system of claim 11, further comprising a controller coupled to the induction motor and the position sensor, the controller being configured to:

determine a relative angular position of the rotor based on the absolute angular position of the rotor; and

provide field-oriented control of the induction motor using the relative angular position of the rotor.

13. The drive system of claim 11, wherein the position sensor is a resolver.

14. The drive system of claim 13, wherein the resolver further comprises:

a resolver rotor coupled to a shaft of the induction motor, wherein the resolver rotor is concentric to and integral with the shaft; and

a resolver stator coupled to the induction motor, wherein the resolver stator is concentric to the resolver rotor.

15. The drive system of claim 14, further comprising a resolver-to-digital converter coupled to the resolver stator, the resolver-to-digital converter being configured to convert signals from the resolver to a digital output.

16. The drive system of claim 15, further comprising a controller coupled to the induction motor and the resolver-to-digital converter, the controller being configured to:

determine a relative angular position of the rotor based on the absolute angular position of the rotor; and

provide field-oriented control of the induction motor using the relative angular position.

17. The drive system of claim 13, wherein the resolver is a two-pole resolver.

18. A method for controlling an induction motor having a rotor, the method comprising:

obtaining an initial angular position of the rotor using an absolute position sensor, wherein the initial angular position of the rotor is obtained when the induction motor is started;

obtaining a subsequent angular position of the rotor using the absolute position sensor;

determining a relative angular position of the rotor based on the initial angular position and the subsequent angular position; and

determining a magnetizing current command based on the relative angular position.

19. The method of claim 18, wherein determining the relative angular position further comprises subtracting the initial angular position from the subsequent angular position, wherein subtracting the initial angular position from the subsequent angular position results in the relative angular position of the rotor.

20. The method of claim 18, further comprising determining a rotor speed based on the relative angular position of the rotor by differentiating the relative angular position with respect to time.