Electric Vehicle Braking Control for Battery Full Charge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric vehicles cannot be smoothly stopped when the battery is in a full charge state due to excessive charging during regenerative braking, leading to the necessity of using friction braking instead.
Innovation Solution
A control device for electric vehicles that determines whether all regenerative electric power is consumed during braking and generates regenerative braking force only when it is, ensuring smooth stopping by adjusting the braking force based on the accelerator pedal opening degree and using a combination of motor and friction braking units controlled by a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is performed when the battery is in a full charge state, then the braking force is generated by the motor, but the battery is excessively charged
Solution Approach 1:
The control device continuously monitors the battery's state of charge and dynamically adjusts the braking force distribution between regenerative braking and friction braking based on real-time feedback. When the battery reaches full charge, the system automatically reduces regenerative braking and compensates with friction braking to prevent overcharging while maintaining smooth deceleration.
Solution Approach 2:
The system dynamically switches between different braking modes (regenerative braking, friction braking, or combination) based on the battery's charge state and vehicle operating conditions. This dynamic adjustment allows the vehicle to optimize braking performance while preventing battery overcharge, transitioning smoothly between braking sources as conditions change.
2Reliability
If friction braking is used instead of regenerative braking when the battery is full, then the battery is protected from overcharging, but the vehicle cannot be smoothly stopped
Solution Approach 1:
The control device merges friction braking and regenerative braking into a coordinated braking system. When the battery is full, friction braking is used as the primary braking source, but the system combines it with residual regenerative braking capability and precise friction braking control to achieve smooth stopping, eliminating the harshness associated with pure friction braking.
Solution Approach 2:
The system changes the braking force distribution parameters dynamically based on battery charge state. When the battery is full, it adjusts the friction braking force magnitude and timing parameters, and combines them with limited regenerative braking parameters, to maintain smooth deceleration characteristics while protecting the battery from overcharge.
3Ease of operation
If regenerative braking is always used for smooth stopping, then the stopping smoothness is improved, but the battery may be excessively charged
Solution Approach 1:
The control system uses real-time feedback on battery charge state to determine the optimal braking strategy. When the battery is not full, it prioritizes regenerative braking for smooth stopping while charging the battery. When the battery approaches full charge, it transitions to friction braking with compensated smoothness control, preventing overcharge while maintaining stopping quality.
Solution Approach 2:
The system dynamically adapts the braking force distribution between regenerative and friction braking based on real-time battery charge conditions. This dynamic adjustment allows the vehicle to maximize regenerative braking benefits when the battery can accept charge, while smoothly transitioning to friction braking when the battery is full, optimizing both stopping smoothness and energy management throughout the charging cycle.
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
Enables smooth stopping of electric vehicles by effectively managing regenerative and friction braking forces, preventing battery overcharging and maintaining efficient energy utilization regardless of the battery's state of charge.
Implementation Method 1
a motor configured to generate a driving force or a regenerative braking force of the electric vehicle
Implementation Method 2
a friction braking unit configured to generate a friction braking force
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A control device is provided for an electric vehicle that generates a braking force corresponding to an opening degree of an accelerator pedal to decelerate the electric vehicle. The control device for the electric vehicle includes a motor configured to generate a driving force or a regenerative braking force of the electric vehicle, a friction braking unit configured to generate a friction braking force, and a controller configured to control at least one of the motor and the friction braking unit corresponding to the opening degree of the accelerator pedal. The controller determines whether all of regenerative electric power generated by the motor is consumed in the electric vehicle when the motor is caused to perform a regenerative braking. The controller causes the motor to perform the regenerative braking when the regenerative electric power is determined to be consumed in the electric vehicle.