Regenerative Braking Torque Control for Electric Vehicles
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Solution Overview
Problem
Existing methods for controlling regenerative braking in electric vehicles often result in insufficient braking force and reduced energy recovery, as the regenerative braking torque is decreased before ABS activation, leading to lower actual braking force and inefficient energy recovery.
Innovation Solution
A method that progressively reduces regenerative braking torque before and during ABS control, detects front wheel slip, and adjusts both regenerative and hydraulic braking torques to ensure adequate braking force, using hydraulic torque if necessary, and continues to decrease regenerative braking torque until the vehicle stops if slip is above a standard value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regenerative braking torque is decreased before ABS activation, then ABS control can be activated, but energy recovery is decreased and actual braking force is lower than goal braking force
Solution Approach 1:
The regenerative braking torque is dynamically adjusted based on wheel slip detection. The system transitions from a static torque reduction approach to a dynamic control strategy where torque is progressively reduced only when slip is detected, allowing the system to adapt to real-time driving conditions and maintain optimal energy recovery while ensuring ABS activation when necessary
Solution Approach 2:
The system implements feedback control by continuously monitoring wheel slip and adjusting regenerative braking torque accordingly. When slip is detected, the controller provides feedback to reduce torque progressively, creating a closed-loop control system that maintains both energy recovery efficiency and proper ABS activation conditions
2Reliability
If regenerative braking torque is decreased before ABS activation, then ABS control can be activated, but actual braking force is lower than goal braking force
Solution Approach 1:
The system merges regenerative braking and hydraulic braking into a unified control system. Rather than treating them as separate systems where one replaces the other, the controller coordinates both systems to work together, using regenerative braking as the primary force and hydraulic braking as supplementary support to maintain goal braking force while enabling ABS activation
Solution Approach 2:
The system applies partial regenerative braking torque reduction only when and where needed (when slip is detected), rather than reducing torque universally before ABS activation. This partial action approach maintains sufficient braking force while creating the conditions necessary for ABS activation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the feeling of braking and improves energy recovery by maintaining sufficient braking force and torque reduction during ABS activation, while optimizing the use of both regenerative and hydraulic braking systems.
Implementation Method 1
an electric vehicle uses regenerative braking
Implementation Method 2
An electric vehicle thus also contains a hydraulic brake system to elicit braking force by oil pressure
Data Source
AI summary
A method for controlling regenerative braking of a vehicle includes: initiating the regenerative braking; detecting an amount of slip of a wheel during the regenerative braking; if the amount of slip is increasing, reducing a regenerative braking torque; and if the amount of slip is greater than a set value, actuating an antilock brake system and reducing the regenerative braking torque or a hydraulic braking torque continuously until the vehicle is stopped. Alternatively, if the amount of slip is increasing, the regenerative braking torque is not reduced.