SYSTEM AND METHOD FOR CONTROLLING REGENERATIVE BRAKING OF ELECTRIC VEHICLE

• US 20160105132A1
• Filed: 12/03/2014
• Published: 04/14/2016
• Est. Priority Date: 10/08/2014
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Kim, Sangjoon
• Granted Patent: US 9,660,558 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 7/10 Dynamic electric regenerative braking B60L7/22 takes precedence
• CPC Class Codes: B60L 7/22 Dynamic electric resistor braking, combined with dynamic electric regenerative braking
• CPC Class Codes: H02P 3/14 by regenerative braking
• 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

Abstract

A system and a method for controlling regenerative braking of an electric vehicle are provided. The system and method calculate an available torque considering a battery system and an available torque considering a motor system to improve an accuracy of regenerative braking amount. The method includes calculating an available torque considering a battery system and an available torque considering a motor system when regenerative braking of the electric vehicle is required and calculating a regenerative braking capacity based on the available torque considering the battery system and the available torque considering the motor system.

Claims

1. A method for controlling regenerative braking of an electric vehicle, comprising:

calculating, by a controller, an available torque considering a battery system and an available torque considering a motor system when regenerative braking of the electric vehicle is required; and

calculating, by the controller, a regenerative braking capacity based on the available torque considering the battery system and the available torque considering the motor system.

2. The method of claim 1, further comprising:

performing, by the controller, regenerative braking based on the regenerative braking capacity after calculating the regenerative braking capacity.

3. The method of claim 1, wherein the available torque considering the battery system is calculated based on a charging possible power of the battery and charging efficiency of the battery.

4. The method of claim 3, wherein the charging possible power of the battery is calculated based on a battery state of charge (SOC), a charging limit power of the battery limited by a battery temperature, and a loss power of a part load.

5. The method of claim 3, wherein the charging efficiency of the battery is calculated based on a maximum charging torque of the motor according to a motor speed.

6. The method of claim 1, wherein the available torque considering the motor system is calculated based on a wheel torque and a derating factor predetermined at a motor power.

7. The method of claim 6, wherein the wheel torque is converted from a motor torque reflecting a gear ratio of a transmission.

8. The method of claim 6, wherein the derating factor is determined at the motor power based on a condition of the motor system.

9. The method of claim 1, wherein the regenerative braking capacity is calculated based on a minimum torque between the available torque considering the battery system and the available torque considering the motor system.

10. A system for controlling regenerative braking of an electric vehicle, comprising:

a motor configured to operate as a power source;

a transmission connected to the motor;

a battery configured to provide a driving voltage to the motor;

a battery management system configured to manage a battery state of charge (SOC);

a driving information detector configured to detect driving information of the electric vehicle;

a brake controller configured to detect a total braking amount based on a signal output from the driving information detector and adjust hydraulic pressure supplied to a brake cylinder of a wheel based on a braking amount of hydraulic pressure; and

a vehicle controller configured to determine whether regenerative braking of the electric vehicle is required based on the signal output from the driving information detector, calculate an available torque considering the battery system based on a signal output from the battery management system and an available torque considering the motor system based on a condition of the motor, and perform regenerative braking by calculating a regenerative braking capacity based on a minimum torque between the available torque considering the battery system and the available torque considering the motor system.

11. The system of claim 10, wherein the driving information detector includes:

a vehicle speed sensor configured to detect a vehicle speed; and

a brake pedal position sensor configured to detect a position value of a brake pedal.

12. The system of claim 10, wherein the vehicle controller is configured to calculate the available torque considering the battery system based on a charging possible power of the battery and charging efficiency of the battery.

13. The system of claim 12, wherein the vehicle controller is configured to calculate the charging possible power of the battery based on a charging limit power of the battery and a loss power of a part load.

14. The system of claim 12, wherein the vehicle controller is configured to calculate the charging efficiency of the battery based on a maximum charging torque of the motor according to a motor speed.

15. The system of claim 10, wherein the vehicle controller is configured to calculate the available torque considering the motor system based on a wheel torque and a derating factor predetermined at a motor power.

16. The system of claim 15, wherein the vehicle controller is configured to convert a motor torque to the wheel torque by reflecting a gear ratio of a transmission.

17. The system of claim 15, wherein the vehicle controller is configured to determine the derating factor at the motor power based on a condition of the motor system.

18. A non-transitory computer readable medium containing program instructions executed by a controller, the computer readable medium comprising:

program instructions that calculate an available torque considering a battery system and an available torque considering a motor system when regenerative braking of the electric vehicle is required; and

program instructions that calculate a regenerative braking capacity based on the available torque considering the battery system and the available torque considering the motor system.

19. The non-transitory computer readable medium of claim 18, further comprising:

program instructions that perform regenerative braking based on the regenerative braking capacity after calculating the regenerative braking capacity.