Increased motor torque capability through time-based thermal derating

Patent metadata

Field	Value
Publication number	US-12512779-B2
Application number	US-202318521226-A
Country	US
Kind code	B2
Filing date	Nov 28, 2023
Priority date	Nov 28, 2023
Publication date	Dec 30, 2025
Grant date	Dec 30, 2025

Abstract

A vehicle includes a system that performs a method of derating a motor of the vehicle. The system includes a timer and a processor. The processor is configured to start the timer when a temperature of a stator of the motor exceeds a high temperature threshold, select a blend ratio based on a time value on the timer, determine, using the blend ratio, an intermediate derating curve for the motor by interpolating between a first derating curve associated with a first target temperature and a second derating curve associated with a second target temperature greater than the first target temperature, and derate the motor along the intermediate derating curve.

First claim

What is claimed is:

1 . A method of derating a motor of a vehicle, comprising:
starting a timer when a temperature of a stator of the motor exceeds a high temperature threshold; selecting a blend ratio based on a time value on the timer; determining, using the blend ratio, an intermediate derating curve for the motor by interpolating between a first derating curve associated with a first target temperature and a second derating curve associated with a second target temperature greater than the first target temperature; and derating the motor along the intermediate derating curve.

2 . The method of claim 1 , wherein the first derating curve is associated with a long-term operation of the motor and the second derating curve is associated with a short-term operation of the motor.

3 . The method of claim 1 , further comprising incrementing the timer between a first time and a second time, determining a first intermediate derating curve at the first time, determining a second intermediate derating curve at the second time, and derating along a resultant derating trajectory that connects a first operating point on the first intermediate derating curve at the first time to a second operating point on the second intermediate derating curve at the second time.

4 . The method of claim 3 , wherein the second intermediate derating curve is closer to the first derating curve than the first intermediate derating curve.

5 . The method of claim 1 , further comprising selecting the blend ratio from a blend curve that relates the blend ratio to time via one of: (i) a sigmoid curve;
and (ii) a modified sigmoid curve.

6 . The method of claim 5 , further comprising storing the blend curve as one of: (i) an equation; and (ii) a look up table.

7 . The method of claim 1 , further comprising increasing a torque at the motor to operate the motor in an extended capacity region between the first target temperature and the second target temperature after the temperature of the motor drops below a recovery temperature threshold.

8 . A system for derating a motor of a vehicle, comprising:
a timer; a processor configured to:
start the timer when a temperature of a stator of the motor exceeds a high temperature threshold;
select a blend ratio based on a time value on the timer; determine, using the blend ratio, an intermediate derating curve for the motor by interpolating between a first derating curve associated with a first target temperature and a second derating curve associated with a second target temperature greater than the first target temperature; and derate the motor along the intermediate derating curve.

9 . The system of claim 8 , wherein the first derating curve is associated with a long-term operation of the motor and the second derating curve is associated with a short-term operation of the motor.

10 . The system of claim 8 , wherein the processor is further configured to increment the timer between a first time and a second time, determining a first intermediate derating curve at the first time, determine a second intermediate derating curve at the second time, and derate along a resultant derating trajectory that connects a first operating point on the first intermediate derating curve at the first time to a second operating point on the second intermediate derating curve at the second time.

11 . The system of claim 10 , wherein the second intermediate derating curve is closer to the first derating curve than the first intermediate derating curve.

12 . The system of claim 8 , wherein the processor is further configured to select the blend ratio from a blend curve that relates the blend ratio to time via one of: (i) a sigmoid curve; and (ii) a modified sigmoid curve.

13 . The system of claim 12 , wherein the processor is further configured to store the blend curve as one of: (i) an equation; and (ii) a look up table.

14 . The system of claim 8 , wherein the processor is further configured to increase a torque at the motor to operate the motor in an extended capacity region between the first target temperature and the second target temperature after the temperature of the motor drops below a recovery temperature threshold.

15 . A vehicle, comprising:
a timer; a processor configured to: start the timer when a temperature of a stator of a motor exceeds a high temperature threshold; select a blend ratio based on a time value on the timer; determine, using the blend ratio, an intermediate derating curve for the motor by interpolating between a first derating curve associated with a first target temperature and a second derating curve associated with a second target temperature greater than the first target temperature; and derate the motor along the intermediate derating curve.

16 . The vehicle of claim 15 , wherein the first derating curve is associated with a long-term operation of the motor and the second derating curve is associated with a short-term operation of the motor.

17 . The vehicle of claim 15 , wherein the processor is further configured to increment the timer between a first time and a second time, determining a first intermediate derating curve at the first time, determine a second intermediate derating curve at the second time, and derate along a resultant derating trajectory that connects a first operating point on the first intermediate derating curve at the first time to a second operating point on the second intermediate derating curve at the second time.

18 . The vehicle of claim 17 , wherein the second intermediate derating curve is closer to the first derating curve than the first intermediate derating curve.

19 . The vehicle of claim 15 , wherein the processor is further configured to select the blend ratio from a blend curve that relates the blend ratio to time via one of: (i) a sigmoid curve; and (ii) a modified sigmoid curve.

20 . The vehicle of claim 15 , wherein the processor is further configured to increase a torque at the motor to operate the motor in an extended capacity region between the first target temperature and the second target temperature after the temperature of the motor drops below a recovery temperature threshold.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Mayberry Michael
• Gagas Brent Steven
• Berry Daniel J

Classifications

• B60L15/20 Primary

  for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed · CPC title

• B60L2240/425

  Temperature · CPC title

• B60L2260/16

  of electrical drive trains · CPC title

• B60L15/209

  for overtaking · CPC title

• B60L3/0061

  relating to electrical machines · CPC title