Electric automobile braking energy recovery control method and system

Abstract

The invention discloses a braking energy recovery control method for an electric vehicle. The method comprises the following specific steps: 1, acquiring an accelerator, a brake pedal, a parking signal, a vehicle speed signal and a battery load value; 2, starting a braking energy feedback mode; 3, the current vehicle speed value is obtained, and the braking torque is obtained; 4, the current state of the power battery is obtained, and the limit braking torque of the power battery is calculated; 5, the current rotating speed of the driving motor is obtained, and the limiting braking torque of the driving motor is calculated; 6, obtaining the maximum feedback torque limit value of the driving motor; 7, comparing the braking torque, the power battery limit value braking torque, the driving motor limit value braking torque and the driving motor maximum feedback torque limit value to obtain a minimum value Tmin; 8, acquiring a feedback torque value Trq of the drive-by-wire ACBS; step 9, comparing the minimum value Tmin and the torque value Trq, and taking the maximum value T as the final feedback torque; and tenthly, electron rotation is controlled to conduct energy recovery according to the final braking target torque.

Description

Technical Field

[0001] This invention relates to the field of automotive energy recovery technology, specifically to a method and system for controlling the braking energy recovery of electric vehicles. Background Technology

[0002] With the increasingly widespread application of new energy vehicles, the research on energy recovery systems is one of their core technologies. An energy recovery system refers to the conversion of a portion of the kinetic energy of a vehicle during deceleration or braking into electrical energy, which is then stored and reused to drive the vehicle. With the increasing scarcity of global energy and the continuous deterioration of environmental problems, the vigorous development of new energy sources is urgently needed to achieve energy conservation and emission reduction and maintain sustainable social development. Compared with traditional vehicles, electric vehicles generally have a shorter driving range due to the lower energy density of their batteries; therefore, the energy-saving issue of electric vehicles has become a key research focus. Summary of the Invention

[0003] I. Technical problems to be solved This invention addresses the shortcomings of existing technologies by proposing a method and system for controlling the regenerative braking of electric vehicles that ensures driving comfort, shortens braking distance, maximizes energy recovery, increases vehicle range, and reduces driver range anxiety.

[0004] II. Specific Technical Solutions A method for controlling regenerative braking energy in electric vehicles, comprising the following steps: Step 1: Obtain accelerator pedal, brake pedal, parking signal, vehicle speed signal, and battery load value; Step 2: Activate the regenerative braking mode; Step 3: Obtain the current vehicle speed value and calculate the braking torque; Step 4: Obtain the current state of the power battery and calculate the limit braking torque of the power battery; Step 5: Obtain the current speed of the drive motor and calculate the limit braking torque of the drive motor; Step 6: Obtain the maximum feedback torque limit of the drive motor; Step 7: Compare the braking torque, the power battery limit braking torque, and the drive motor limit braking torque. The minimum value Tmin is obtained from the torque and the maximum feedback torque limit of the drive motor. Step 8: Obtain the ACBS feedback torque value Trq; Step 9: Compare the minimum value Tmin and the torque value Trq, and take the larger value T as the final feedback torque; Step 10: Control the electronic rotation to recover energy based on the final braking target torque.

[0005] As a preferred method: In step one, the vehicle is powered on and in motion. The corresponding statuses of the accelerator pedal, brake pedal, handbrake, and gear position signals are collected via hard wiring. The vehicle speed signal and SOC value are obtained via the CAN bus. When all signal statuses meet the conditions for brake energy recovery, the vehicle enters the brake energy recovery mode.

[0006] A system for controlling regenerative braking energy in an electric vehicle includes: a vehicle speed calculation module for calculating braking torque; a power battery current state acquisition module for calculating the power battery's limit braking torque; a drive motor current speed acquisition module for calculating the drive motor's allowable braking torque; a drive motor maximum allowable braking torque acquisition module for acquiring the drive motor's maximum allowable braking torque value; an ACBS feedback braking torque acquisition module for acquiring the ACBS feedback braking torque value; and a comparison and minimum value module for comparing and selecting the minimum value among the braking torque, the power battery's limit braking torque, the drive motor's allowable braking torque, and the drive motor's maximum allowable braking torque value. A comparison and larger value module is provided, which compares the minimum value obtained by the comparison and smaller value module with the ACBS feedback braking torque value and takes the larger value. It is equipped with a final target braking torque module for the motor to control the motor to perform energy recovery.

[0007] The beneficial effects of this invention are as follows: by using braking deceleration, reduction ratio, tire radius, curb weight and ACBS-calculated torque as the standard for energy recovery, it can not only ensure driving comfort and shorten braking distance, but also maximize energy recovery, improve the vehicle's range, and reduce the driver's range anxiety. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0009] Figure 2 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0010] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0011] like Figure 1 The following is a method for controlling regenerative braking energy in electric vehicles, comprising the following steps: Step 1: Obtain accelerator pedal, brake pedal, parking signal, vehicle speed signal, and battery load value; Step 2: Activate the regenerative braking mode; Step 3: Obtain the current vehicle speed value and calculate the braking torque; Step 4: Obtain the current state of the power battery and calculate the limit braking torque of the power battery; Step 5: Obtain the current speed of the drive motor and calculate the limit braking torque of the drive motor; Step 6: Obtain the maximum feedback torque limit of the drive motor; Step 7: Compare the braking torque, the power battery limit braking torque, and the drive motor limit braking torque. The minimum value Tmin is obtained from the torque and the maximum feedback torque limit of the drive motor. Step 8: Obtain the ACBS feedback torque value Trq; Step 9: Compare the minimum value Tmin and the torque value Trq, and take the larger value T as the final feedback torque; Step 10: Control the electronic rotation to recover energy based on the final braking target torque.

[0012] When the vehicle is powered on and in motion, the corresponding status of the accelerator pedal, brake pedal, handbrake, and gear position signals is collected via hard wiring. The vehicle speed signal and SOC value are obtained via the CAN bus. When all signal statuses meet the conditions for brake energy regeneration, the vehicle is enabled to enter brake energy recovery mode.

[0013] The current vehicle speed signal and brake pedal position signal are interpolated to obtain the pedal feedback torque MAP, and the initial feedback torque 1 is obtained. The vehicle speed-brake pedal position feedback torque MAP is calculated by vehicle curb weight * vehicle deceleration at each calibrated vehicle speed * tire radius / vehicle final drive ratio.

[0014] The bus obtains the current maximum allowable regenerative torque of the power battery.

[0015] The current motor speed is obtained from the bus, and the motor speed-torque MAP is interpolated to obtain the allowable feedback torque of 3 at the current motor speed.

[0016] The maximum permissible feedback torque of the motor is obtained from the bus.

[0017] Take the minimum value Tmin among the feedback torques 1, 2, 3, and 4.

[0018] The bus obtains the feedback torque Trq under the current braking state of ACBS.

[0019] The maximum value of Tmin and Trq is taken as the final braking energy feedback torque.

[0020] Energy is recovered by controlling the motor's rotation using the motor's final feedback torque.

[0021] After obtaining the final feedback torque from the motor, it is sent to the motor controller, which then controls the motor to rotate and recover energy.

[0022] like Figure 2 As shown in the above embodiment, the system structure adopted is an electric vehicle braking energy recovery control system. It includes a vehicle speed calculation module for calculating braking torque; a power battery current state acquisition module for calculating the power battery's limit braking torque; a drive motor current speed acquisition module for calculating the drive motor's allowable braking torque; a drive motor maximum allowable braking torque acquisition module for acquiring the drive motor's maximum allowable braking torque value; an ACBS feedback braking torque acquisition module for acquiring the ACBS feedback braking torque value; a comparison and minimum value module for comparing the braking torque, power battery limit braking torque, drive motor allowable braking torque, and drive motor maximum allowable braking torque value to select the smallest value; a comparison and maximum value module for comparing the minimum value obtained by the comparison and minimum value module with the ACBS feedback braking torque value and selecting the larger value; and a final motor target braking torque module for controlling the motor to perform energy recovery.

[0023] The automotive braking energy recovery strategy provided in this application first interpolates the initial feedback torque of the motor based on the vehicle's current speed and brake pedal position. Then, the bus obtains the battery's current maximum allowable feedback torque. Next, based on the motor's rotational speed, the current feedback torque of the motor is interpolated. Finally, the bus obtains the motor's maximum allowable feedback torque. The smallest absolute value among the four—motor initial feedback torque, battery allowable feedback torque, motor feedback torque, and motor maximum allowable feedback torque—is selected as the motor reference feedback torque Tmin. Simultaneously, the current feedback torque Trq calculated by ACBS on the bus is obtained and compared with the motor reference feedback torque Tmin; the larger value is taken as the final energy feedback target torque. The final motor feedback torque is then used to recover the vehicle's braking energy. Compared to existing technologies, this method, by using braking deceleration, reduction ratio, tire radius, curb weight, and torque calculated by ACBS as standards for energy recovery, not only ensures driving comfort and shortens braking distance but also maximizes energy recovery, increases vehicle range, and reduces driver range anxiety.

[0024] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims.

Claims

1. A method for controlling regenerative braking energy in electric vehicles, characterized in that, The specific steps are as follows: Step 1: Obtain accelerator pedal, brake pedal, parking signal, vehicle speed signal, and battery load value; Step 2: Activate the regenerative braking mode; Step 3: Obtain the current vehicle speed value and calculate the braking torque; Step 4: Obtain the current state of the power battery and calculate the limit braking torque of the power battery; Step 5: Obtain the current speed of the drive motor and calculate the limit braking torque of the drive motor; Step 6: Obtain the maximum feedback torque limit of the drive motor; Step 7: Compare the braking torque, the power battery limit braking torque, and the drive motor limit braking torque. The minimum value Tmin is obtained from the torque and the maximum feedback torque limit of the drive motor. Step 8: Obtain the ACBS feedback torque value Trq; Step 9: Compare the minimum value Tmin and the torque value Trq, and take the larger value T as the final feedback torque; Step 10: Control the electronic rotation to recover energy based on the final braking target torque.

2. The electric vehicle braking energy recovery control method according to claim 1, characterized in that: In step one, the vehicle is powered on and in motion. The corresponding statuses of the accelerator pedal, brake pedal, handbrake, and gear position signals are collected via hard wiring. The vehicle speed signal and SOC value are obtained via the CAN bus. When all signal statuses meet the conditions for brake energy regeneration, the vehicle enters the brake energy recovery mode.

3. The system of the electric vehicle braking energy recovery control method according to claim 1 or 2, characterized in that: The system includes: a vehicle speed calculation module for calculating braking torque; a power battery current status acquisition module for calculating the power battery's limit braking torque; a drive motor current speed acquisition module for calculating the drive motor's allowable braking torque; a drive motor maximum allowable braking torque acquisition module for obtaining the drive motor's maximum allowable braking torque value; an ACBS feedback braking torque acquisition module for obtaining the ACBS feedback braking torque value; and a comparison and minimum value module for comparing the braking torque, power battery limit braking torque, drive motor allowable braking torque, and drive motor maximum allowable braking torque value and selecting the minimum value. A comparison and larger value module is provided, which compares the minimum value obtained by the comparison and smaller value module with the ACBS feedback braking torque value and takes the larger value. It is equipped with a final target braking torque module for the motor to control the motor to perform energy recovery.

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