EV Braking Torque Blending Under Regenerative Power Limits
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Solution Overview
Problem
Electric vehicles experience inconsistent deceleration and safety risks when in energy recovery limited states due to limited battery or motor capabilities, leading to an unsatisfactory driving experience.
Innovation Solution
A method and apparatus that determine the vehicle's energy recovery state and adjust braking torque by controlling electric and hydraulic braking systems based on vehicle status, including disabling or enabling regenerative braking systems to maintain stability and optimize energy recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If energy recovery strategy is used during coasting to improve endurance capability, then energy recovery capability is improved, but deceleration performance deteriorates when battery temperature is low or battery level is high
Solution Approach 1:
The braking system dynamically adjusts the mixing ratio between electric braking torque and hydraulic braking torque based on real-time battery state (temperature, charge level). When battery conditions are favorable, electric braking dominates for energy recovery; when conditions are unfavorable, hydraulic braking compensates to maintain deceleration performance. This dynamic adaptation resolves the contradiction between energy recovery capability and deceleration reliability.
Solution Approach 2:
The system changes the operating parameters of the braking system by adjusting the proportion of electric and hydraulic braking torques according to battery state parameters. The control method modifies the braking torque distribution parameters in real-time: increasing hydraulic braking component when battery temperature is low or charge level is high, and increasing electric braking component when battery conditions are optimal, thereby maintaining consistent deceleration performance while maximizing energy recovery opportunities.
2Loss of energy
If electric braking torque is increased to improve energy recovery, then energy recovery torque is improved, but braking system complexity increases due to torque mixing control
Solution Approach 1:
The braking control system incorporates feedback mechanisms that continuously monitor battery state (temperature, charge level) and adjust the electric-hydraulic braking torque mixing ratio accordingly. The control unit receives feedback on battery conditions and automatically optimizes the braking torque distribution, maximizing energy recovery while maintaining simple and reliable control logic through rule-based decision making.
3Reliability
If hydraulic braking is used to compensate for insufficient energy recovery, then deceleration performance is improved, but energy recovery capability deteriorates
Solution Approach 1:
The system applies partial hydraulic braking compensation only when necessary (when battery state indicates limited energy recovery capability). Instead of always using maximum hydraulic braking to ensure deceleration performance, the system uses the minimum necessary hydraulic braking to supplement electric braking when battery conditions prevent adequate energy recovery, thereby maintaining deceleration reliability while preserving energy recovery opportunities.
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
Ensures stable and efficient braking performance, providing a safer and more comfortable driving experience by optimizing energy recovery and maintaining chassis braking system stability.
Implementation Method 1
a power system of the vehicle may operate as a generator, to convert kinetic energy into electric energy
Implementation Method 2
determining a hydraulic braking torque of the vehicle based on a target energy recovery torque and a maximum allowed energy recovery torque
Data Source
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AI summary
A braking method and apparatus, and a vehicle are disclosed. The method includes: obtaining a recharge power capability value of a vehicle; determining an electric braking torque of the vehicle as a preset value when the recharge power capability value is less than or equal to a first threshold, and determining a hydraulic braking torque of the vehicle based on a target energy recovery torque and a maximum allowed energy recovery torque of the vehicle; or determining, based on a traveling parameter of the vehicle, the electric braking torque and the hydraulic braking torque when the recharge power capability value is greater than a second threshold; and sending first indication information, where the first indication information includes the hydraulic braking torque, or the first indication information includes the electric braking torque and the hydraulic braking torque. According to the method, whether the vehicle is in an energy recovery limited state can be determined in time and accurately, to bring good driving experience to a user.