Brake Force Handover When Regenerative Braking Stops at Full SOC
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Solution Overview
Problem
Regenerative braking in vehicles is abruptly stopped to prevent battery overcharging, leading to a loss of braking power and increased vehicle speed on downhill roads, especially in commercial vehicles, posing a risk of accidents.
Innovation Solution
A device and method that includes a regenerative braking stop logic unit, a trigger signal generator, and a target braking force calculation unit to maintain braking force by converting regenerative braking into physical braking when the battery reaches its upper limit, considering vehicle attitude, weight, deceleration, and regenerative braking type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regenerative braking is forcibly stopped to prevent battery overcharging, then battery safety is improved, but braking power is lost and vehicle speed increases rapidly
Solution Approach 1:
The patent introduces an intermediary control system that detects when regenerative braking must be stopped due to battery SOC reaching the upper limit. This intermediary controller then activates friction braking as a substitute, ensuring continuous braking force. The intermediary acts as a bridge between the regenerative braking system and friction braking system, maintaining braking power while protecting battery safety.
Solution Approach 2:
The patent changes the braking force parameter by switching from regenerative braking to friction braking when battery SOC reaches the upper limit. The controller adjusts the braking force distribution parameter in real-time, ensuring that the total braking force remains sufficient even when regenerative braking is discontinued. This parameter change maintains braking effectiveness while preventing battery overcharging.
2Reliability
If regenerative braking is forcibly stopped when battery reaches upper limit SOC, then battery overcharging is prevented, but vehicle acceleration occurs on downhill roads
Solution Approach 1:
The patent implements preliminary action by detecting when battery SOC approaches the upper limit before complete overcharging occurs. The controller proactively switches from regenerative to friction braking in advance, preventing the situation where regenerative braking must be abruptly stopped. This preliminary transition prevents vehicle acceleration on downhill roads while maintaining battery safety margins.
Solution Approach 2:
The patent ensures continuity of useful braking action by seamlessly transitioning from regenerative braking to friction braking. The controller maintains continuous braking force application without interruption, preventing vehicle acceleration. The useful action of braking continues uninterrupted, first through regenerative means and then through friction braking when battery SOC reaches the upper limit.
3Ease of operation
If pedal value is immediately transmitted to accelerate when regenerative braking is disabled, then driver input responsiveness is improved, but dangerous acceleration occurs
Solution Approach 1:
The patent applies preliminary anti-action by detecting when regenerative braking is disabled due to battery SOC reaching the upper limit. Before the driver's pedal input can cause dangerous acceleration, the controller preemptively applies friction braking to counteract the acceleration tendency. This preliminary counter-action prevents dangerous vehicle acceleration while maintaining appropriate responsiveness to driver input.
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
Prevents sudden acceleration on downhill roads by maintaining braking force through conversion, ensuring stable vehicle operation and safety.
Implementation Method 1
regenerative braking or the like utilizes inertial force generated when a motor (an electric motor) moving by torque force is in a closed loop state to turn the rotor on the wheel or the like to operate the motor as a generator. Accordingly, braking power may be exerted using electrical energy recovered by converting kinetic energy.
Data Source
AI summary
A device for controlling vehicle braking includes a regenerative braking stop logic unit forcibly stopping regenerative braking of a vehicle when a battery charge state of the vehicle reaches a battery upper limit charge state during the regenerative braking, a trigger signal generator generating a trigger signal when the vehicle is driving when the regenerative braking is forcibly stopped by the regenerative braking stop logic unit, and a target braking force calculation unit initiating an operation according to the trigger signal, obtaining a converted braking force value based on a regenerative braking force value obtained from a total vehicle braking force value immediately before forced cessation of the regenerative braking, and determining target physical braking force using the converted braking force value.