System and method for controlling torque in an electrical machine

• US 6,465,977 B1
• Filed: 11/29/2001
• Issued: 10/15/2002
• Est. Priority Date: 11/29/2001
• Status: Expired due to Term

• Current Assignee: Vitesco Technologies USA, LLC (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Ecostar Electric Drive Systems, LLC (Continental AG)
• Inventors: Reddy, Vinod, Farkas, Kenneth James
• Primary Examiner(s): Masih, Karen
• Application Number:
  US09/683,176
• Time in Patent Office: 320 Days
• Field of Search: 318/432, 318/25.1, 318/138, 318/439, 318/629, 318/701, 318/807
• US Class Current: 318/432
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

System and method for controlling the output torque of an electrical machine include a torque controller operable for receiving a motor input command, representative of a desired output torque, and generating a drive command to direct a motor to produce a predetermined output torque based on the motor input command. Further, the torque controller may include a sensor system for generating a feedback signal representative of an actual output torque of the motor. Additionally, the torque controller includes an input modulator and a speed modulator for adjusting the drive command based on the feedback signal and based on the motor input command to control a value of the predetermined output torque and to control a rate at which the predetermined output torque reaches the desired output torque.

Claims

1. An electrical machine, comprising:

a motor operable to produce a predetermined output torque based on a drive command;

a torque controller operable for receiving a motor input command and generating the drive command, the torque controller comprising an input modulator having;

a hysteresis module having a predetermined hysteresis function, wherein the hysteresis module is operable for receiving the motor input command and generating a hysteresis signal according to the hysteresis function;

a shaping module having a predetermined shaping function, wherein the shaping module is operable for receiving the hysteresis signal and generating a shaping signal according to the shaping function;

a filtering module having a predetermined filtering function, wherein the filtering module is operable for receiving the shaping signal and generating a filtering signal according to the filtering function; and

wherein the filtering signal comprises the drive command.

2. The electrical machine of claim 1, further comprising:

a feedback module having a predetermined feedback function, wherein the feedback module is operable for changing a function selected from the group consisting of the predetermined hysteresis function, the predetermined shaping function, and the predetermined filtering function based on the motor input command.

3. The electrical machine of claim 1, further comprising:

a feedback module having a predetermined feedback function, wherein the feedback module is operable for changing the predetermined filtering function based on the filtering signal determined from the motor input command and the shaping signal determined from a later-received motor input command.

4. The electrical machine of claim 1, wherein the motor input command comprises an accelerator position signal representative of an actual accelerator pedal position.

5. The electrical machine of claim 1, wherein the motor input command comprises an accelerator position signal representative of an actual accelerator pedal position and a relative accelerator pedal position.

6.The electrical machine of claim 1, wherein the motor input command comprises an accelerator position signal representative of a desired output torque and a desired output torque direction.

6. The electrical machine of claim 1, wherein the predetermined hysteresis function, at least in part, produces a first constant output for a plurality of variable inputs.

7. The electrical machine of claim 1, wherein the predetermined shaping function produces an output that either lags or leads an associated input.

8. The electrical machine of claim 1, wherein the predetermined filtering function adjusts a rate at which the predetermined output torque leads or lags a desired output torque represented by the motor input command.

9. An electrical machine, comprising:

a motor operable to produce a predetermined output torque in a predetermined torque direction based on a drive command;

a sensor system operable to estimate or detect an actual output torque and an actual torque direction and generate a feedback signal representative thereof;

a torque controller operable for receiving a motor input command and the feedback signal and generating the drive command, wherein the motor input command represents a desired output torque and a desired torque direction, the torque controller comprising a speed modulator having;

a torque analyzer operable for selecting one of a plurality of slew rates, based on the motor input command and the feedback signal, and operable for generating the drive command as a function of the selected slew rate, the motor input command and the feedback signal.

10. The electrical machine of claim 10, further comprising:

wherein the torque analyzer is operable to determine a motor state selected from the group consisting of increasing motoring torque, decreasing motoring torque, increasing regenerative torque and decreasing regenerative torque, wherein motoring torque is a value of output torque in a first direction and the regenerative torque is a value of output torque in a second direction opposite the first direction; and

wherein the plurality of slew rates comprise a first slew rate associated with the increasing motoring torque, a second slew rate associated with the decreasing motoring torque, a third slew rate associated with the increasing regenerative torque, and a fourth slew rate associated with the decreasing regenerative torque.

11. An electrical machine, comprising:

a motor operable to produce a predetermined output torque based on a drive command;

a sensor system operable to estimate or detect an actual output torque and an actual torque direction and generate a feedback signal representative thereof;

a torque controller operable for receiving a motor input command and the feedback signal and generating the drive command, wherein the motor input command represents a desired output torque and a desired torque direction, the torque controller comprising an input modulator and a speed modulator;

the input modulator comprising;

a hysteresis module having a predetermined hysteresis function, wherein the hysteresis module is operable for receiving the motor input command and generating a hysteresis signal according to the hysteresis function;

a shaping module having a predetermined shaping function, wherein the shaping module is operable for receiving the hysteresis signal and generating a shaping signal according to the shaping function; and

a filtering module having a predetermined filtering function, wherein the filtering module is operable for receiving the shaping signal and generating a filtering signal according to the filtering function;

the speed modulator comprising;

a torque analyzer operable for selecting one of a plurality of slew rates, based on the filtering signal and the feedback signal, and operable for generating the drive command as a function of the selected slew rate, the filtering signal and the feedback signal.

12. The electrical machine of claim 12, further comprising:

a feedback module having a predetermined feedback function, wherein the feedback module is operable for changing a function selected from the group consisting of the predetermined hysteresis function, the predetermined shaping function, and the predetermined filtering function based on the motor input command.

13. The electrical machine of claim 12, further comprising:

wherein the torque analyzer is operable to determine a motor state selected from the group consisting of increasing motoring torque, decreasing motoring torque, increasing regenerative torque and decreasing regenerative torque, wherein motoring torque is a value of output torque in a first direction and the regenerative torque is a value of output torque in a second direction opposite the first direction; and

wherein the plurality of slew rates comprise a first slew rate associated with the increasing motoring torque, a second slew rate associated with the decreasing motoring torque, a third slew rate associated with the increasing regenerative torque, and a fourth slew rate associated with the decreasing regenerative torque.

14. A method of controlling an amount of torque produced by an electrical machine, comprising:

receiving a raw accelerator position signal (APS) representative of an actual accelerator position;

receiving relative accelerator position signal representative of a change in the actual accelerator position;

generating a first adjusted APS according to a predetermined hysteresis function and based on the raw APS and the relative accelerator position;

generating a second adjusted APS according to a predetermined shaping function and based on the first adjusted APS, where the second adjusted APS lags or leads the raw APS;

generating a third adjusted APS according to a predetermined filtering function based on the second adjusted APS, where the filtering function includes a predetermined modulation factor that varies depending upon the relative accelerator position; and

controlling the amount of torque produced by the electrical machine based on a torque command, where the torque command comprises the third adjusted APS.

15. The method of claim 15, where the predetermined hysteresis function is selected from a plurality of hysteresis functions based on a desired difference between the raw APS and the first adjusted APS associated with a given value of the raw APS and a given value of the change in the actual accelerator position.

16. The method of claim 15, where the predetermined shaping function is selected from a plurality of shaping functions based on a desired difference between the first adjusted APS and the second adjusted APS associated with a given value of the actual accelerator position.

17. The method of claim 15, where the modulation factor is selected from a plurality of modulation factors according to a difference between the second adjusted APS and the third adjusted APS.

18. The method of claim 15, where the modulation factor is selected from a first constant modulation factor, a second constant modulation factor and a third interpolated modulation factor depending on a difference between the second adjusted APS and the third adjusted APS.

19. The method of claim 19, where a value of the first constant modulation factor is greater than a value of the second constant modulation factor, and where an increase in the value of the modulation factor decreases the lead or lag of the third adjusted APS with respect to the raw APS.

20. The method of claim 20, where a value of the interpolated modulation factor is greater than a value of the first constant modulation factor and less than a value of the second constant modulation factor.

21. A method of controlling an amount of torque produced by an electrical machine, comprising:

receiving an input torque command representative of an actual accelerator position and a relative accelerator position;

receiving a feedback signal representative of an actual rotational direction of a motor associated with the electrical machine;

selecting one of a plurality of slew rates based on the input torque command and the feedback signal; and

generating a drive command to control the amount of torque produced by the electrical machine, where the drive command is a function of the selected slew rate and the input torque command.

22. A method of controlling an amount of torque produced by an electrical machine, comprising:

receiving a raw accelerator position signal (APS) representative of an actual accelerator position;

receiving relative accelerator position signal representative of a change in the actual accelerator position;

generating a first adjusted APS according to a predetermined hysteresis function and based on the raw APS and the relative accelerator position;

generating a second adjusted APS according to a predetermined shaping function and based on the first adjusted APS, where the second adjusted APS lags or leads the raw APS;

generating a third adjusted APS according to a predetermined filtering function based on the second adjusted APS, where the filtering function includes a predetermined modulation factor that varies depending upon the relative accelerator position;

receiving a feedback signal representative of an actual rotational direction of a motor associated with the electrical machine;

selecting one of a plurality of slew rates based on the third adjusted APS and the feedback signal; and

generating a drive command to control the amount of output torque produced by the electrical machine, where the drive command is a function of the selected slew rate and the third adjusted APS.