MOTOR CONTROL SYSTEM TO COMPENSATE FOR TORQUE RIPPLE

• US 20140265961A1
• Filed: 03/12/2013
• Published: 09/18/2014
• Est. Priority Date: 03/12/2013
• Status: Active Grant

• Current Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Inventors: Gebregergis, Abraham, Islam, Mohammad S., Sebastian, Tomy, Chowdhury, Mazharul H., RajaVenkitasubramony, Ramakrishnan, Popy, Niharika P., Hossain, Shakil
• Granted Patent: US 9,136,785 B2
• Time in Patent Office: Days
• US Class Current: 318/400.23
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: H02P 21/05 specially adapted for damping motor oscillations, e.g. for reducing hunting
• CPC Class Codes: H02P 21/22 Current control, e.g. using a current control loop
• CPC Class Codes: H02P 29/50 Reduction of harmonics
• CPC Class Codes: H02P 6/10 Arrangements for controlling torque ripple, e.g. providing reduced torque ripple

Abstract

A motor control system is provided. The motor control system includes a motor having plurality of motor harmonics, and a torque ripple compensation controller in communication with the motor. The torque ripple compensation controller is configured to determine a harmonic ripple current for a corresponding one of the plurality of motor harmonics. The harmonic ripple current is based on a reference q-axis current and a reference d-axis current. The torque ripple compensation controller is configured to add the harmonic ripple current for each of the plurality of motor harmonics together to determine the ripple compensating current.

Claims

1. A motor control system, comprising:

a motor having plurality of motor harmonics; and

a torque ripple compensation controller in communication with the motor, the torque ripple compensation controller configured to;

determine a harmonic ripple current for a corresponding one of the plurality of motor harmonics, the harmonic ripple current based on a reference q-axis current and a reference d-axis current; and

add the harmonic ripple current for each of the plurality of motor harmonics together to determine a ripple compensating current.

2. The motor control system of claim 1, wherein the torque ripple compensation controller includes a plurality of look-up tables, wherein each of the plurality of look-up tables are used to determine one of a torque ripple magnitude and a torque ripple phase for one of the plurality of motor harmonics.

3. The motor control system of claim 2, wherein values for the torque ripple magnitude and the torque ripple phase are based on cogging torque characteristics of the motor.

4. The motor control system of claim 2, wherein the torque ripple compensation controller calculates a current harmonic q-axis magnitude based on the torque ripple magnitude.

5. The motor control system of claim 2, wherein the torque ripple compensation controller calculates a current q-axis phase output based on the torque ripple phase.

6. The motor control system of claim 5, wherein the current q-axis phase output is determined by:

MtrCurrQax_—

iPhase=sign(Iq_ref)t_MtrTrq_ripple_—

iPh(n)

wherein MtrCurrQax_iPhase is the current q-axis phase output, Iq_ref is the reference q-axis current, and t_MtrTrq_ripple_iPh(n) is the torque ripple phase found in one of the plurality of look-up tables for an i^th harmonic.

7. The motor control system of claim 2, wherein the torque ripple compensation controller calculates a current harmonic d-axis magnitude based on the torque ripple magnitude.

8. The motor control system of claim 2, wherein the torque ripple compensation controller calculates a current d-axis phase output based on the torque ripple phase.

9. The motor control system of claim 1, wherein the ripple compensating current is a q-axis ripple compensating current, and determined by:

10. The motor control system of claim 1, wherein the ripple compensating current is a d-axis ripple compensating current, and determined by:

11. A method of motor control for a motor having a plurality of motor harmonics, comprising:

determining a harmonic ripple current for a corresponding one of the plurality of motor harmonics by a torque ripple compensation controller, the harmonic ripple current based on a reference q-axis current and a reference d-axis current; and

adding the harmonic ripple current for each of the plurality of motor harmonics together to determine a ripple compensating current.

12. The method of claim 11, further comprising including a plurality of look-up tables with the torque ripple compensation controller, wherein each of the plurality of look-up tables are used to determine one of a torque ripple magnitude and a torque ripple phase for one of the plurality of motor harmonics.

13. The method of claim 12, wherein values for the torque ripple magnitude and the torque ripple phase are based on cogging torque characteristics of the motor.

14. The method of claim 12, further comprising calculating a current harmonic q-axis magnitude by the torque ripple compensation controller based on the torque ripple magnitude.

15. The method of claim 12, further comprising calculating a current q-axis phase output by the torque ripple compensation controller based on the torque ripple phase.

16. The method of claim 15, wherein a harmonic ripple current is a harmonic q-axis ripple current, and determined by:

MtrCurrQax_—

iPhase=sign(Iq_ref)t_MtrTrq_ripple_—

iPh(n)

wherein MtrCurrQax_iPhase is the current q-axis phase output, Iq_ref is the reference q-axis current, and t_MtrTrqripple_iPh(n) is the torque ripple phase found in one of the plurality of look-up tables for an i^th harmonic.

17. The method of claim 12, wherein the torque ripple compensation controller calculates a current harmonic d-axis magnitude based on the torque ripple magnitude.

18. The method of claim 12, wherein the torque ripple compensation controller calculates a current d-axis phase output based on the torque ripple phase.

19. The method of claim 11, wherein the ripple compensating current is a q-axis ripple compensating current, and determined by:

20. The method of claim 11, wherein the ripple compensating current is a d-axis ripple compensating current, and determined by: