Drive control system for electric motor and method of controlling electric motor

• US 9,604,623 B2
• Filed: 11/13/2013
• Issued: 03/28/2017
• Est. Priority Date: 12/14/2012
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Ide, Hirohito
• Primary Examiner(s): Olszewski, John R
• Assistant Examiner(s): McPherson, James M
• Application Number:
  US14/078,535
• Publication Number:
  US 20140172209A1
• Time in Patent Office: 1,231 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2240/465 Slip
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 2250/24 by lever actuation
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 3/106 for maintaining or recovering the adhesion of the drive wheels
• CPC Class Codes: B60L 50/62 charged by low-power generators primarily intended to support the batteries, e.g. range extenders
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2510/082 Speed change rate
• CPC Class Codes: B60W 2710/081 : Speed
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 2710/182 : Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 30/18036 : Reversing
• CPC Class Codes: B60W 30/18172 : Preventing, or responsive to skidding of wheels
• CPC Class Codes: B60W 30/20 : Reducing vibrations in the driveline
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• 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
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

A drive control system for an electric motor includes a slippage determination device, a tentative vibration damper torque calculator, a vibration damper torque limit value setting device, a vibration damper torque setting device, and a control device. The vibration damper torque setting device is configured to set a control torque obtained by limiting a tentative vibration damper torque using a limit value set by the vibration damper torque limit value setting device. The control device is configured to control driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque set by the vibration damper torque setting device.

Claims

1. A drive control system for an electric motor, comprising:

an electronic control unit programmed to;

determine whether a drive wheel of a vehicle slips, the determination that the drive wheel slips being maintained for a predetermined period of time after the drive wheel slips;

calculate a tentative vibration damper torque to reduce a variation component of a rotational speed of one of

a drive axle mechanically connected to the drive wheel, and

the electric motor mounted in the vehicle as a drive source;

set a limit value to limit the vibration damper torque to reduce the variation component of the rotational speed of one of the drive axle and the electric motor, the limit value including a positive vibration damper torque limit value and a negative vibration damper torque limit value based upon rotational vibration of the drive axle, the electric motor or both;

for the predetermined period of time after the determination that the drive wheel slips, reduce the limit value of the positive vibration damper torque limit value or the negative vibration damper torque limit value that is in a same direction as a rotational direction of the drive axle, the electric motor or both;

set a control torque obtained by limiting the tentative vibration damper torque using the limit value; and

control driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque so that an amount of the vibration damper torque applied to the one of the drive axle and the electric motor in the same direction as the rotational direction of the one of the drive axle and the electric motor is reduced.

2. The drive control system according to claim 1, wherein the slippage determination device determines that the drive wheel slips if a variation in the rotational speed of the electric motor per unit time is higher than or equal to a predetermined value.

3. The drive control system according to claim 1, wherein the slippage determination device determines that the drive wheel slips if a variation in the rotational speed of the drive axle per unit time is higher than or equal to a predetermined value.

4. The drive control system according to claim 1, wherein the predetermined period of time is longer than one cycle time of a resonance frequency of rotational fluctuation caused by torsion of the drive axle.

5. The drive control system according to claim 1, wherein the vibration damper torque limit value setting device is configured to set a positive limit value and a negative limit value of the vibration damper torque as the limit value.

10. The drive control system according to claim 5, wherein the vibration damper torque setting device is configured to limit the tentative vibration damper torque within a range from the positive limit value to the negative limit value.

6. A drive control system for an electric motor, comprising:

slippage determination means for determining whether a drive wheel of a vehicle slips, the slippage determination means maintains the determination that the drive wheel slips for a predetermined period of time after the drive wheel slips;

tentative vibration damper torque calculating means for calculating a tentative vibration damper torque to reduce a variation component of a rotational speed of one of

a drive axle mechanically connected to the drive wheel, and

the electric motor mounted in the vehicle as a drive source;

vibration damper torque limit value setting means for setting a limit value to limit the vibration damper torque to reduce the variation component of rotational speed of one of the drive axle and the electric motor, the limit value including a positive vibration damper torque limit value and a negative vibration damper torque limit value based upon rotational vibration of the drive axle, the electric motor or both, wherein the vibration damper torque limit value setting means, for the predetermined period of time after the determination that the drive wheel slips, reduces the limit value of the positive vibration damper torque limit value or the negative vibration damper torque limit value that is in a same direction as a rotational direction of the drive axle, the electric motor or both;

vibration damper torque setting means for setting a control torque obtained by limiting the tentative vibration damper torque using the limit value set by the vibration damper torque limit value setting means; and

control means for controlling driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque set by the vibration damper torque setting means so that an amount of the vibration damper torque applied to the one of the drive axle and the electric motor in the same direction as the rotational direction of the one of the drive axle and the electric motor is reduced.

15. The drive control system according to claim 6,

wherein the vibration damper torque limit value setting means is configured to set a positive limit value and a negative limit value of the vibration damper torque as the limit value, and

wherein the vibration damper torque setting means is configured to limit the tentative vibration damper torque within a range from the positive limit value to the negative limit value.

7. A method of controlling an electric motor, the method comprising:

determining whether a drive wheel of a vehicle slips;

maintaining the determination that the drive wheel slips for a predetermined period of time after the drive wheel slips;

calculating a tentative vibration damper torque to reduce a variation component of a rotational speed of one of

a drive axle mechanically connected to the drive wheel, and

the electric motor mounted in the vehicle as a drive source;

setting a limit value to limit the vibration damper torque to reduce the variation component of rotational speed of one of the drive axle and the electric motor, the limit value including a positive vibration damper torque limit value and a negative vibration damper torque limit value based upon rotational vibration of the drive axle, the electric motor or both;

for the predetermined period of time after the determination that the drive wheel slips, reducing the limit value of the positive vibration damper torque limit value or the negative vibration damper torque limit value that is in a same direction as a rotational direction of the drive axle, the electric motor or both;

setting a control torque obtained by limiting the tentative vibration damper torque using the limit value; and

controlling driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque so that an amount of the vibration damper torque applied to the one of the drive axle and the electric motor in the same direction as the rotational direction of the one of the drive axle and the electric motor is reduced.

8. A drive control system for an electric motor, comprising:

an electronic control unit programmed to;

determine whether a drive wheel of a vehicle slips, the determination that the drive wheel slips being maintained for a predetermined period of time after the drive wheel slips;

calculate a tentative vibration damper torque to reduce a variation component of a rotational speed of one of

a drive axle mechanically connected to the drive wheel, and

the electric motor mounted in the vehicle as a drive source;

set, for the predetermined period of time after the determination that the drive wheel slips, a limit value to limit a vibration damper torque that increases an absolute value of the rotational speed of the electric motor or the drive axle;

set a control torque obtained by limiting the tentative vibration damper torque using the limit value; and

control driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque,

wherein the predetermined period of time is set in accordance with a resonance frequency of rotational fluctuation caused by torsion of the drive axle.

9. The drive control system according to claim 8, wherein the predetermined period of time is set to a time longer than one cycle time of the resonance frequency of rotational fluctuation caused by torsion of the drive axle.

11. A drive control system for an electric motor, comprising:

an electronic control unit programmed to;

determine whether a drive wheel of a vehicle slips, the determination that the drive wheel slips being maintained for a predetermined period of time after the drive wheel slips;

calculate a tentative vibration damper torque to reduce a variation component of a rotational speed of one of

a drive axle mechanically connected to the drive wheel, and

the electric motor mounted in the vehicle as a drive source;

set, for the predetermined period of time after the determination that the drive wheel slips, a limit value to limit a vibration damper torque that increases an absolute value of the rotational speed of the electric motor or the drive axle;

set a control torque obtained by limiting the tentative vibration damper torque using the limit value; and

control driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque,

wherein the vibration damper torque limit value setting device is configured to set a positive limit value and a negative limit value of the vibration damper torque as the limit value,

wherein the vibration damper torque setting device is configured to limit the tentative vibration damper torque within a range from the positive limit value to the negative limit value, and

wherein the positive limit value to the negative limit value are set on a basis of a shift position of a gear shift operation unit of the vehicle.

12. The drive control system according to claim 11, wherein the gear shift operation unit includes a forward drive shift position and a reverse shift position.

13. A drive control system for an electric motor, comprising:

slippage determination means for determining whether a drive wheel of a vehicle slips, the slippage determination means maintains the determination that the drive wheel slips for a predetermined period of time after the drive wheel slips;

tentative vibration damper torque calculating means for calculating a tentative vibration damper torque to reduce a variation component of a rotational speed of one of

a drive axle mechanically connected to the drive wheel, and

the electric motor mounted in the vehicle as a drive source;

vibration damper torque limit value setting means for setting, for the predetermined period of time after the slippage determination means determines that the drive wheel slips, a limit value to limit a vibration damper torque that increases an absolute value of the rotational speed of the electric motor or the drive axle;

vibration damper torque setting means for setting a control torque obtained by limiting the tentative vibration damper torque using the limit value set by the vibration damper torque limit value setting means; and

control means for controlling driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque set by the vibration damper torque setting means,

wherein the predetermined period of time is set in accordance with a resonance frequency of rotational fluctuation caused by torsion of the drive axle.

14. The drive control system according to claim 13, wherein the predetermined period of time is set to a time longer than one cycle time of the resonance frequency of rotational fluctuation caused by torsion of the drive axle.

16. A drive control system for an electric motor, comprising:

slippage determination means for determining whether a drive wheel of a vehicle slips, the slippage determination means maintains the determination that the drive wheel slips for a predetermined period of time after the drive wheel slips;

tentative vibration damper torque calculating means for calculating a tentative vibration damper torque to reduce a variation component of a rotational speed of one of

a drive axle mechanically connected to the drive wheel, and

the electric motor mounted in the vehicle as a drive source;

vibration damper torque limit value setting means for setting, for the predetermined period of time after the slippage determination means determines that the drive wheel slips, a limit value to limit a vibration damper torque that increases an absolute value of the rotational speed of the electric motor or the drive axle;

vibration damper torque setting means for setting a control torque obtained by limiting the tentative vibration damper torque using the limit value set by the vibration damper torque limit value setting means; and

control means for controlling driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque set by the vibration damper torque setting means,

wherein the vibration damper torque limit value setting means is configured to set a positive limit value and a negative limit value of the vibration damper torque as the limit value,

wherein the vibration damper torque setting means is configured to limit the tentative vibration damper torque within a range from the positive limit value to the negative limit value, and

wherein the positive limit value to the negative limit value are set on a basis of a shift position of a gear shift operation unit of the vehicle.

17. The drive control system according to claim 16, wherein the gear shift operation unit includes a forward drive shift position and a reverse shift position.

18. A method of controlling an electric motor, the method comprising:

determining whether a drive wheel of a vehicle slips;

maintaining the determination that the drive wheel slips for a predetermined period of time after the drive wheel slips;

calculating a tentative vibration damper torque to reduce a variation component of a rotational speed of one of

a drive axle mechanically connected to the drive wheel, and

the electric motor mounted in the vehicle as a drive source;

setting, for the predetermined period of time after it is determined that the drive wheel slips, a limit value to limit a vibration damper torque that increases an absolute value of the rotational speed of the electric motor or the drive axle;

setting a control torque obtained by limiting the tentative vibration damper torque using the limit value; and

controlling driving of the electric motor in accordance with a command value of a torque obtained by combining a requested torque for the electric motor with the control torque,

wherein the predetermined period of time is set in accordance with a resonance frequency of rotational fluctuation caused by torsion of the drive axle.

19. The method according to claim 18, wherein the predetermined period of time is set to a time longer than one cycle time of the resonance frequency of rotational fluctuation caused by torsion of the drive axle.