Regenerative Braking Control for Discrete Gear Shifts
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Solution Overview
Problem
In vehicles with discrete variable transmissions, precise control of regenerative braking during gear shifting is challenging, leading to variations in deceleration and sudden changes in hydraulic braking, which deteriorate braking linearity and stability.
Innovation Solution
A method to determine and control regenerative braking by considering motor characteristics, specifically deciding the motor torque mode (constant power or constant torque) and using calculated gear ratios to adjust regenerative braking amounts during gear shifts, ensuring stable braking without deceleration changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is applied during gear shifting in a vehicle with discrete variable transmission, then fuel efficiency is improved through energy recovery, but deceleration stability deteriorates due to difficulty in precisely controlling regenerative braking amount
Solution Approach 1:
The patent applies parameter changes by detecting motor operating parameters (torque, speed, temperature) and adjusting regenerative braking control parameters accordingly. The control unit modifies regenerative braking torque based on motor state changes during gear shifting, ensuring stable deceleration while maximizing energy recovery. This resolves the contradiction by dynamically adapting control parameters to maintain stability without sacrificing energy efficiency.
Solution Approach 2:
The patent implements feedback control by continuously monitoring actual deceleration and regenerative braking torque, then adjusting the regenerative braking amount based on detected deviations. The control unit uses feedback from motor current, voltage, and mechanical state sensors to maintain precise control during gear shifting, resolving the stability issue while preserving energy recovery benefits.
2Adaptability or versatility
If regenerative braking amount is adjusted during gear shifting, then braking adaptability is improved, but braking linearity deteriorates due to sudden changes in hydraulic braking amount
Solution Approach 1:
The patent applies preliminary action by predicting gear shifting events and pre-adjusting regenerative braking torque before the actual shift occurs. The control unit detects gear shift intentions through transmission control unit signals and proactively modifies regenerative braking to compensate for upcoming changes, preventing sudden hydraulic braking adjustments and maintaining braking linearity while adapting to gear changes.
Solution Approach 2:
The patent implements dynamics by continuously adapting regenerative braking control based on real-time motor characteristics and transmission state. The control unit dynamically adjusts regenerative braking torque according to motor speed-torque curves and gear ratio changes, ensuring smooth transitions that maintain braking linearity while providing adaptability to varying operating conditions during gear shifting.
3Measurement precision
If motor characteristics are considered for regenerative braking control, then braking precision is improved, but control complexity increases due to multiple operating modes
Solution Approach 1:
The patent manages control complexity through parameter changes by using pre-defined motor torque-speed characteristic curves and lookup tables that simplify real-time control calculations. The control unit selects appropriate control parameters based on current operating mode (constant torque, constant power, or base speed regions), avoiding complex real-time optimization while maintaining high braking precision through mode-specific parameter adjustment.
Solution Approach 2:
The patent applies segmentation by dividing the motor operating range into distinct regions (constant torque region, constant power region, base speed region) with different control strategies. The control unit determines the current operating region and applies appropriate control parameters for each segment, simplifying the overall control logic while maintaining precision across the full operating range through region-specific optimization.
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 braking by accurately determining regenerative braking amounts based on motor torque modes and gear ratios, minimizing deceleration variations and enhancing braking linearity during gear shifts, thus improving fuel efficiency and user safety.
Implementation Method 1
The regenerative braking technology is a technology to generate electrical energy by applying a reverse torque to an electric motor
Implementation Method 2
The electrical energy generated is stored in a high-voltage battery to be used later to power the motor
Data Source
AI summary
A method for controlling regenerative braking of a vehicle is provided, in which a driving area of a motor is decided when shifting gears during regenerative braking, and an amount of regenerative braking is determined based on the decided result. The method includes a first process of deciding whether motor torque is in a constant power mode, a second process of deciding whether the motor torque is in a constant torque mode, and a third process of deciding whether the mode of the motor torque is converted into the constant torque mode from the constant power mode.