Regenerative Braking Torque Control for Stable EV Coasting
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Solution Overview
Problem
Existing eco-friendly vehicles experience instability and disconnection of driving during coasting on low-friction roads due to wheel slip generated by regenerative braking torque, leading to frequent activation and deactivation of the Anti-lock Brake System (ABS), which disrupts stability and regenerative braking.
Innovation Solution
A system and method using Proportional-Integral (PI) control to quickly reduce and maintain wheel slip below a reference level by controlling regenerative braking torque to zero when ABS is activated and gradually increasing it to a target level when ABS is deactivated, while compensating for wheel speed differences and preventing misjudgment of wheel slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high regenerative braking torque is set to increase energy collection ratio, then energy collection efficiency is improved, but wheel slip is generated on low-friction roads
Solution Approach 1:
The patent applies dynamics by making the regenerative braking torque adjustable and adaptive rather than fixed. The control unit dynamically adjusts the torque level based on real-time wheel slip detection and road friction conditions, allowing the system to optimize energy collection while preventing wheel slip when detected
Solution Approach 2:
The patent implements feedback control through wheel speed sensors that continuously monitor wheel rotation. When wheel slip is detected through comparison of wheel speeds, the control unit receives feedback and adjusts the regenerative braking torque accordingly, reducing torque when slip occurs and restoring it when slip stops
2Loss of energy
If regenerative braking torque is increased to charge battery during coasting, then energy recovery is improved, but wheel slip control is compromised on low-friction roads
Solution Approach 1:
The system dynamically adjusts regenerative braking torque based on real-time conditions. The control unit modifies the torque level adaptively, allowing high torque for energy recovery when conditions permit, and reducing torque when wheel slip begins, thus balancing energy collection with wheel slip control
Solution Approach 2:
The patent changes the torque parameter dynamically based on wheel slip detection. The control unit modifies the regenerative braking torque parameter in response to wheel speed variations, enabling the system to optimize between energy recovery and maintaining proper wheel traction
3Reliability
If ABS is activated to secure braking stability during wheel slip, then wheel slip is prevented, but regenerative braking is stopped disrupting continuity
Solution Approach 1:
The patent applies dynamics by making the regenerative braking torque adjustable rather than fixed. The control unit dynamically adjusts the torque level based on real-time wheel slip detection and road friction conditions, allowing the system to optimize energy collection while preventing wheel slip when detected
Solution Approach 2:
The patent implements feedback control through wheel speed sensors that continuously monitor wheel rotation. When wheel slip is detected through comparison of wheel speeds, the control unit receives feedback and adjusts the regenerative braking torque accordingly, reducing torque when slip occurs and restoring it when slip stops
4Measurement precision
If wheel speed detection is used for slip control, then wheel slip can be detected, but misjudgment occurs due to tire radius variations and air pressure differences
Solution Approach 1:
The system dynamically adjusts regenerative braking torque based on real-time conditions. The control unit modifies the torque level adaptively, allowing high torque for energy recovery when conditions permit, and reducing torque when wheel slip begins, thus balancing energy collection with wheel slip control
Solution Approach 2:
The patent changes the torque parameter dynamically based on wheel slip detection. The control unit modifies the regenerative braking torque parameter in response to wheel speed variations, enabling the system to optimize between energy recovery and maintaining proper wheel traction
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 stabilizes coasting and ensures continuous regenerative braking by minimizing frequent ABS activation, maintaining wheel slip below the reference level, and securing accuracy and stability of slip control.
Implementation Method 1
regenerative braking that operates a motor as a power generator to charge a battery by collecting inertia energy
Data Source
AI summary
Proposed is a system and method of controlling regenerative braking torque of an eco-friendly vehicle, the system and method being configured to quickly reduce and maintain a wheel slip amount less than a reference value during coasting, and accordingly, being able to achieve coasting stability and stable regenerative braking, by controlling regenerative brake into zero when a wheel slip over a reference value is generated and an Anti-lock Brake System (ABS) is turned on while an eco-friendly vehicle coasts, and by gradually increasing regenerative braking torque of a motor with a predetermined inclination from zero using Proportional-Integral (PI) control when the ABS is turned off.