Dual-Motor Regenerative Braking Under Battery Input Limits
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Solution Overview
Problem
Existing electric vehicles face insufficient deceleration when the battery input limit occurs, leading to inadequate braking force without hydraulic brake usage.
Innovation Solution
A vehicle equipped with a PM motor and an SR motor, each with different loss characteristics, is controlled to regenerate power using the motor with greater loss characteristics during battery input limits, ensuring braking force without relying on hydraulic brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is in a fully charged state or low temperature state causing input limit of power, then the battery cannot accept more regenerative power, but the deceleration becomes insufficient and braking force is lost
Solution Approach 1:
The patent segments the regenerative braking function across two different motors (PM motor and SR motor) with different loss characteristics. When battery input limit occurs, the system switches to using the motor with greater loss characteristic for regeneration, dividing the braking function between different motor types to ensure continuous braking capability despite battery limitations.
Solution Approach 2:
The patent changes the operational parameters by selecting different motors based on battery state. When battery input limit is detected, the system changes which motor performs regeneration (switching from the more efficient motor to the motor with greater loss characteristic), thereby adapting the regenerative braking parameter to current battery conditions while maintaining braking force.
2Loss of energy
If regenerative braking is used to maximize energy recovery, then energy efficiency is improved, but when battery input limit occurs the braking force becomes insufficient
Solution Approach 1:
The patent implements dynamic switching between different motors for regenerative braking based on real-time battery state. The system continuously monitors battery charge state and temperature, and dynamically selects which motor (PM or SR) should perform regeneration, allowing the system to adapt to changing battery capacity for energy acceptance and maintain both energy efficiency and braking reliability.
Solution Approach 2:
The patent uses feedback from battery state detection (charge state, temperature, power input limit status) to control which motor performs regeneration. The detection device monitors battery conditions and provides feedback to the control device, which then selects the appropriate motor for regenerative braking, ensuring both energy recovery and sufficient braking force are maintained.
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
Secures braking force even when battery power limits occur, reducing hydraulic brake usage and enhancing its durability.
Implementation Method 1
a plurality of motors having different loss characteristics during regeneration from each other, a battery that can be charged by power generated during the regeneration of each of the plurality of motors
Data Source
AI summary
A vehicle includes: a plurality of motors having different loss characteristics during regeneration from each other, a battery that can be charged by power generated during the regeneration of each of the plurality of motors; a detection device for detecting power information related to a power state of the battery; and a control device for causing a motor, which has a greater loss characteristic of the regeneration than that of other motors among the plurality of motors, to perform the regeneration when determining that the battery is performing an input limit of the power at the time of the regeneration based on the power information.