Regenerative Braking Torque Control During Shifting
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Solution Overview
Problem
Existing regenerative braking systems in electric vehicles incorrectly calculate braking torque during shifting, leading to a loss of driver intention and reduced fuel efficiency due to increased torque intervention from clutch and brake element slips.
Innovation Solution
A system and method that determine actual shifting conditions to adjust regenerative braking torque, maintaining pre-intervention motor torque during shifting and increasing it post-shifting to accurately reflect driver braking intent, thereby preventing incorrect calculations and enhancing braking sense and fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If regenerative braking is calculated using pre-intervention motor torque during shifting, then the calculation is simple, but the braking force is lost and driver intention is not reflected
Solution Approach 1:
The system dynamically adjusts the torque reference based on shifting state. During shifting, the controller detects the shifting condition and switches to using post-intervention motor torque instead of pre-intervention torque, allowing the control parameter to adapt dynamically to the current operating condition and accurately reflect driver intention
Solution Approach 2:
The system implements feedback by continuously monitoring the shifting state and adjusting the torque calculation accordingly. The controller receives feedback about whether shifting is occurring and modifies the regenerative braking calculation method in real-time, ensuring that the braking force accurately reflects driver intention during shifting operations
2Measurement precision
If torque intervention is increased during shifting to compensate for clutch and brake element slips, then the output shaft torque estimation is improved, but the input shaft torque is reduced and driver intention is lost
Solution Approach 1:
The system takes preliminary action by detecting the shifting state in advance and preemptively adjusting the torque reference before the braking force loss occurs. By identifying the shifting condition early, the controller can switch to the appropriate torque calculation method and prevent the loss of driver intention rather than attempting to compensate after the fact
3Use of energy by moving object
If regenerative braking is maintained during shifting, then fuel efficiency is improved, but incorrect calculations occur when braking starts during shifting
Solution Approach 1:
The system uses feedback to continuously monitor both the shifting state and braking demand. When braking starts during shifting, the controller detects the change in braking demand and adjusts the regenerative braking calculation accordingly, maintaining fuel efficiency while ensuring accurate calculations through real-time feedback about operating conditions
Data Source
AI summary
A system and method for controlling a regenerative braking are provided. The system includes a driving information detector that is configured to detect whether a brake pedal is operated and detect shift information. In addition, a hybrid control unit is configured to fix the regenerative braking during actual shifting based on the shift information and is configured to use a required braking force when the actual shifting is not performed to calculate the regenerative braking.