US-12623660-B2 - Performing static heating of electric motor based on vehicle inclination

Abstract

A computer-implemented method of performing static heating of an electric motor comprises: applying a brake to a wheel of a vehicle that has an electric motor; determining an incline of the vehicle; and in response to the incline being within a first incline range, providing first current to the electric motor for static heating, the first current selected so as to not produce torque in the electric motor.

Inventors

• Fabrice Anthony Paccoret
• David Anthony Lickfold
• Sai Rajeev Devaragudi
• Jamie Wardlaw

Assignees

• ATIEVA, INC.

Dates

Publication Date

20260512

Application Date

20221017

Claims (18)

1. 1 . A computer-implemented method of performing static heating of an electric motor, the method comprising: applying a brake to a wheel of a vehicle that has the electric motor; determining an incline of the vehicle; and in response to the incline being within a first incline range, providing first current to the electric motor for static heating, the first current selected so as to not produce torque in the electric motor.
2. 2 . The computer-implemented method of claim 1 , wherein the first incline range extends from zero incline to a first incline value.
3. 3 . The computer-implemented method of claim 2 , further comprising also providing the first current to the electric motor for static heating in response to the incline being within a second incline range extending from a second incline value to at least a third incline value, the second incline value greater than the first incline value.
4. 4 . The computer-implemented method of claim 1 , further comprising providing second current to the electric motor for static heating in response to the incline being within a second incline range separate from the first incline range, the second current selected so as to not produce torque in the electric motor.
5. 5 . The computer-implemented method of claim 4 , wherein the second incline range is greater than the first incline range.
6. 6 . The computer-implemented method of claim 4 , wherein the second current is different from the first current.
7. 7 . The computer-implemented method of claim 4 , wherein the brake is applied by a braking system configured to take the incline into account.
8. 8 . The computer-implemented method of claim 7 , wherein the braking system is configured to apply the brake with a first clamp force up to a first incline, and to apply the brake with a second clamp force greater than the first clamp force above the first incline.
9. 9 . The computer-implemented method of claim 8 , wherein the first incline is greater than the first incline range.
10. 10 . The computer-implemented method of claim 9 , wherein the second incline range begins substantially at the first incline.
11. 11 . The computer-implemented method of claim 1 , further comprising selecting the first current based on the incline.
12. 12 . The computer-implemented method of claim 1 , wherein the brake is a parking brake.
13. 13 . The computer-implemented method of claim 1 , wherein determining the incline involves using an output of an inertial measurement unit.
14. 14 . The computer-implemented method of claim 1 , wherein determining the incline involves determining a location where the vehicle is parked, and looking up a recorded grade for the location.
15. 15 . The computer-implemented method of claim 14 , wherein determining the location involves using a global positioning system receiver.
16. 16 . The computer-implemented method of claim 1 , further comprising determining if the vehicle is electrically plugged in while parked, and in response to the vehicle being electrically plugged in to charge a battery of the vehicle, limiting the first current for static heating.
17. 17 . The computer-implemented method of claim 16 , wherein the first current is limited so that there is positive current flowing into the battery.
18. 18 . A system configured to perform the method of claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a 35 U.S.C. § 371 National Phase Entry Application from PCT Application No. PCT/US2022/078217, filed on Oct. 17, 2022, entitled “PERFORMING STATIC HEATING OF ELECTRIC MOTOR BASED ON VEHICLE INCLINATION”, and designating the U.S., which claims priority to U.S. Patent Application No. 63/262,910, filed on Oct. 22, 2021, and entitled “PERFORMING STATIC HEATING OF ELECTRIC MOTOR BASED ON VEHICLE INCLINATION,” the disclosures of which are incorporated by reference herein in their entireties. TECHNICAL FIELD This document relates to performing static heating of an electric motor based on a vehicle inclination. BACKGROUND In recent years, electric vehicle (EV) technology has continued to develop, and an increasing number of people are choosing to have an EV as a personal vehicle. An EV has an onboard battery pack or other energy storage. Cells used in battery packs may be associated with a minimum temperature below which the cells cannot be charged. Also, for an optimum charging efficiency, and/or to optimize discharging, the cells may need to be at a substantially higher temperature than the minimum temperature. SUMMARY In a first aspect, a computer-implemented method of performing static heating of an electric motor comprises: applying a brake to a wheel of a vehicle that has an electric motor; determining an incline of the vehicle; and in response to the incline being within a first incline range, providing first current to the electric motor for static heating, the first current selected so as to not produce torque in the electric motor. Implementations can include any or all of the following features. The first incline range extends from zero incline to a first incline value. The computer-implemented method further comprises also providing the first current to the electric motor for static heating in response to the incline being within a second incline range extending from a second incline value to at least a third incline value, the second incline value greater than the first incline value. The computer-implemented method further comprises providing second current to the electric motor for static heating in response to the incline being within a second incline range separate from the first incline range, the second current selected so as to not produce torque in the electric motor. The second incline range is greater than the first incline range. The second current is different from the first current. The brake is applied by a braking system configured to take the incline into account. The braking system is configured to apply the brake with a first clamp force up to a first incline, and to apply the brake with a second clamp force greater than the first clamp force above the first incline. The first incline is greater than the first incline range. The second incline range begins substantially at the first incline. The computer-implemented method further comprises selecting the first current based on the incline. The brake is a parking brake. Determining the incline involves using an output of an inertial measurement unit. Determining the incline involves determining a location where the vehicle is parked, and looking up a recorded grade for the location. Determining the location involves using a global positioning system receiver. The computer-implemented method further comprises determining if the vehicle is electrically plugged in while parked, and in response to the vehicle being electrically plugged in to charge a battery of the vehicle, limiting the first current for static heating. The first current is limited so that there is positive current flowing into the battery. In a second aspect, a system is configured to perform any of the methods of the first aspect above. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 schematically shows an example of an electric vehicle positioned at an incline. FIG. 2 schematically shows an example of a drivetrain for an EV. FIG. 3 shows a block diagram of a system to determine an incline for an EV. FIG. 4 shows a flowchart of an example of a method. FIG. 5 shows a diagram with examples of incline ranges. Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION This document describes examples of systems and techniques for performing static heating of an electric motor based on a vehicle incline. When static heating is performed, it is not intended that the electric motor should produce any torque. However, it is possible that the electric motor inadvertently produces torque during the static heating. A brake (e.g., a parking brake) can therefore be applied during the static heating. Generally, any brake can react up to a maximum amount of torque before slipping or deformation may occur, and this can be referred to as the brake torque limit. If the vehicle is parked at an incline with the brake engaged, this puts a static load on the brake that reduces the amount of inadvertently produced