Dynamic Neutral Point Torque Control for Electric Vehicle Regenerative Braking
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Solution Overview
Problem
Existing methods for controlling regenerative braking in electric and hybrid vehicles are costly and do not effectively manage torque variations based on battery charge levels, nor do they preserve driver comfort by providing an intuitive pedal experience.
Innovation Solution
A method that uses an electronic control unit to impose motor or resistive torque on the wheels based on the accelerator pedal position, with torque regulation curves that vary continuously with battery charge and speed, ensuring seamless transitions between driving and braking modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is applied to recover kinetic energy during deceleration, then energy efficiency is improved, but driver comfort deteriorates due to unnatural pedal behavior when battery is fully charged
Solution Approach 1:
The patent applies dynamics by making the neutral point position variable rather than fixed. The neutral point dynamically adjusts its position on the pedal travel range based on battery charge state (SOC). When battery SOC is high, the neutral point shifts to maintain natural pedal feel; when SOC is low, it shifts to enable maximum regenerative braking. This dynamic adaptation resolves the contradiction between energy recovery and driver comfort.
Solution Approach 2:
The patent changes the parameter of neutral point position based on battery charge state. By modifying this critical parameter dynamically, the system transitions between different operating modes: full regenerative braking when battery needs charging, and natural pedal behavior when battery is full. This parameter change strategy enables the system to optimize both energy recovery and driver comfort under different conditions.
2Adaptability or versatility
If the neutral point is fixed on the accelerator pedal travel, then device complexity is reduced, but adaptability deteriorates because regenerative braking cannot be optimized based on battery charge levels
Solution Approach 1:
The patent makes the existing accelerator pedal serve multiple functions dynamically. The same pedal structure is used for both natural acceleration (when battery is full) and regenerative braking control (when battery needs charging), depending on the neutral point's dynamic position. This multi-functionality approach enables adaptability without adding separate control mechanisms, thus avoiding increased device complexity.
Solution Approach 2:
The patent creates a virtual neutral point through software control rather than adding physical components. The neutral point is a computational concept implemented in the control unit that determines torque distribution based on pedal position and battery SOC. This virtual copying approach provides adaptability while keeping the physical device simple.
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 allows for intuitive driver control of torque, optimizing energy recovery and battery management while maintaining vehicle comfort by smoothly adapting to battery charge levels, thus enhancing driving experience and energy efficiency.
Implementation Method 1
the motor being capable of operating as a generator to recharge the battery by decelerating the vehicle
Implementation Method 2
A method for controlling the torque at the wheels of a vehicle equipped with at least one electric motor... uses an electronic control unit to impose motor or resistive torque on the wheels based on the accelerator pedal position
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a method for controlling the torque applied to the wheels (3, 5) of a vehicle including at least one electric motor (8) connected to a battery (9) and connected to at least one driving wheel (5). The motor is capable of operating as a generator for recharging the battery when the vehicle slows down. A first braking adjustment travel and a second acceleration adjustment travel are applied to the movement of the acceleration pedal (18) of the vehicle, the braking adjustment travel being a continuously decreasing function relative to the charge of the battery.