Slip detection and mitigation for an electric drive powertrain having a high ratio traction drive transmission

Patent metadata

Field	Value
Publication number	US-12017635-B2
Application number	US-202217934154-A
Country	US
Kind code	B2
Filing date	Sep 21, 2022
Priority date	Sep 20, 2018
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A method of controlling a continuously variable electric drivetrain (CVED) including a high ratio traction drive transmission and at least one of a first motor-generator and a second motor-generator is disclosed. The method includes the steps of receiving an output speed, determining a kinematic output speed, and determining a slip state of the high ratio traction drive transmission based on a comparison of the output speed to the kinematic output speed.

First claim

What is claimed is:

1. A continuously variable electric drivetrain, comprising:
a traction drive transmission;
a first motor-generator and a second motor-generator coupled to the traction drive transmission; and
an electronic controller configured to:
receive a measured speed of a first rotating member of the continuously variable electric drivetrain;
determine a calculated speed of the first rotating member or one of the motor-generators;
determine a slip state of the traction drive transmission based on a comparison of the calculated speed and the measured speed; and
if the traction drive transmission is determined to be in a state of slip, then mitigate the state of slip by adjusting a power ratio between the first motor-generator and the second motor-generator by switching the first motor-generator from a torque-control mode to a speed-control mode.

2. The continuously variable electric drivetrain of claim 1 , wherein the traction drive transmission comprises a ring member, a carrier having a plurality of traction members, and a sun member.

3. The continuously variable electric drivetrain of claim 1 , wherein the traction drive transmission comprises a traction ring, a sun roller, and a set of reaction rollers configured to provide torque dependent pressure to a set of floating traction rollers.

4. The continuously variable electric drivetrain of claim 2 , wherein the ring member is a traction ring, the sun member is a sun roller mounted on an input shaft which forms a center roller of a first planetary traction roller including the traction ring arranged radially outward of the sun roller, and the plurality of traction members includes a set of planetary traction rollers disposed in a space between the traction ring and the sun roller.

5. A method of controlling a drivetrain, comprising:
receiving a measured speed of a first rotating member of a continuously variable electric drivetrain;
determining a calculated speed of the first rotating member or a motor;
determining a slip state of a traction drive transmission based on a comparison of the calculated speed and the measured speed;
determining a type of the slip state based on:
a second comparison of a measured speed of a second rotating member to a second measured speed, and
a third comparison of a measured speed of a third rotating member to a third measured speed; and

if the traction drive transmission is determined to be in a state of slip, then mitigating the state of slip based on a speed of the motor connected to the traction drive transmission by switching the motor from a torque-control mode to a speed-control mode.

6. The method of claim 5 , wherein the traction drive transmission is a high ratio traction drive comprising a ring member, a carrier configured to support a plurality of traction members, and a sun member.

7. The method of claim 5 , wherein the motor is a first motor,
wherein the traction drive transmission comprises a ring member, a carrier, and a sun member, and one of the ring member, the carrier, and the sun member is coupled to the first motor, and
wherein one of the ring member, the carrier, and the sun member is coupled to a second motor.

8. The method of claim 5 , wherein determining the calculated speed of the first rotating member is based on a speed of the motor.

9. The method of claim 5 , wherein:
the second comparison comprises comparing a measured speed of a ring member of the traction drive transmission to a measured speed of the motor;
the third comparison comprises comparing a measured speed of a sun member of the traction drive transmission and a measured speed of a second motor; and
the mitigating the slip is based on the determined type of the slip state.

10. The method of claim 9 , wherein determining the type of the slip state comprises determining that the slip state is due to a degraded gear responsive to the measured speed of the ring member being substantially equal to the measured speed of the motor and the measured speed of the sun member being substantially equal to the measured speed of the second motor.

11. The method of claim 10 , wherein taking an action based on the determined type of the slip state comprises disabling the first motor-generator and the second motor-generator responsive to determining that the slip state is due to a degraded transfer gear.

12. The method of claim 5 , wherein determining the type of the slip state comprises determining that the slip state is a ring slip responsive to a speed of a ring member of the traction drive transmission not being substantially equal to the speed of the motor and a speed of a sun member of the traction drive transmission being substantially equal to a speed of a second motor.

13. The method of claim 5 , wherein the motor is a first motor and determining the type of the slip state comprises determining that the slip state is an indeterminate slip responsive to a speed of a ring member of the traction drive transmission not being equal to a speed of the first motor and a speed of a sun member not being equal to a speed of a second motor.

14. A method of controlling a continuously variable electric drivetrain, comprising:
measuring an output speed of the continuously variable electric drivetrain;
determining a second output speed of the continuously variable electric drivetrain;
determining a slip state of a traction drive transmission based on an output comparison of the output speed to the second output speed; and
in response to determining a positive slip state:
performing a first comparison of a speed of a ring member of the traction drive transmission and a first motor speed;
performing a second comparison of a speed of a sun member of the traction drive transmission and a second motor speed; and
determining a fault based on the first comparison and the second comparison.

15. The method of claim 14 , wherein the fault is determined as a ring slip if:
a result of the first comparison is speeds that are not equal and a result of the second comparison is substantially equal speeds; and
the fault is determined as a sun member slip if:
the result of the first comparison is speeds that are substantially equal and the result of the second comparison is substantially equal speeds.

16. The method of claim 15 , further comprising:
in response to determining the fault is ring slip:
adjusting a power ratio between a first motor and a second motor by switching the first motor from a torque-control mode to a speed-control mode; and

in response to determining the fault is sun member slip:
adjusting the power ratio between the first motor and the second motor by switching the second motor from the torque-control mode to the speed-control mode.

17. The method of claim 14 , wherein the first motor is coupled to the sun member, a carrier is stationary, and the ring member is configured to output rotational power.

18. The method of claim 14 , wherein the fault is determined as a damaged gear if results of the first comparison and the second comparison are substantially equal speeds.

19. The method of claim 9 , wherein the second comparison comprises comparing a measured speed of a ring member of the traction drive transmission to a measured speed of the motor, and
wherein the third comparison comprises comparing a measured speed of a sun member of the traction drive transmission and a measured speed of a second motor.

Assignees

• Dana Automotive Systems Group

Inventors

• David Jeffrey M
• Miller Travis J

Classifications

• F16H2059/465

  Detecting slip, e.g. clutch slip ratio · CPC title

• F16H59/38

  of gearing elements · CPC title

• B60W10/115

  with planetary gears · CPC title

• Y02T10/62

  Hybrid vehicles · CPC title

• F16H2057/012

  of gearings · CPC title