EV Regenerative Braking Control With Time-Based SOP Transition
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Solution Overview
Problem
Existing regeneration power control in electric vehicles excessively limits power to prevent battery electrodeposition and deterioration, leading to energy losses and poor power consumption efficiency.
Innovation Solution
A control device for electric vehicles that sets short and long time State Of Power (SOP) limits for battery charging, calculates a transition regeneration State Of Power (SOP) based on these limits, and smoothly transitions between them during regeneration power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regeneration power is limited to prevent battery electrodeposition and deterioration, then battery reliability is improved, but energy loss increases and power consumption cannot be improved
Solution Approach 1:
The patent applies dynamics by making the regeneration power limit variable rather than fixed. The control device dynamically adjusts the regeneration power limit based on the estimated remaining time of regeneration power generation. When the remaining time is short, a higher power limit is applied; when the remaining time is long, a lower power limit is applied. This dynamic adjustment resolves the contradiction by allowing high power (reducing energy loss) when time permits, while protecting the battery when charging time is sufficient.
Solution Approach 2:
The patent changes the parameter of regeneration power limit based on the duration of regeneration power generation. By estimating the remaining time and adjusting the power limit accordingly, the system optimizes the balance between energy recovery and battery protection. This parameter change approach allows the system to maximize energy recovery when time is limited while preventing electrodeposition when time is sufficient.
2Reliability
If regeneration power is set to be relatively small to prevent battery electrodeposition, then battery protection is improved, but regeneration power is excessively limited and energy losses increase
Solution Approach 1:
The system dynamically adjusts the regeneration power limit based on the estimated remaining time. When the remaining time is short, the power limit is set higher to maximize energy recovery. When the remaining time is long, the power limit is set lower to protect the battery. This dynamic approach resolves the contradiction between battery protection and maximizing regeneration power.
Solution Approach 2:
The control device performs preliminary action by estimating the remaining time of regeneration power generation before setting the power limit. This advance estimation allows the system to pre-determine the appropriate power limit that balances battery protection with energy recovery efficiency, avoiding excessive limitation of regeneration power.
3Reliability
If regeneration power is immediately reduced to 0 when regeneration time exceeds predetermined time, then battery electrodeposition is prevented, but energy losses are large and power consumption cannot be improved
Solution Approach 1:
Instead of immediately reducing power to 0 when time exceeds the threshold, the system dynamically adjusts the power limit based on the estimated remaining time. This gradual and conditional reduction prevents electrodeposition while minimizing energy losses by maintaining higher power levels when the remaining time suggests it is safe to do so.
Solution Approach 2:
The system uses feedback by continuously monitoring the duration of regeneration power generation and adjusting the power limit accordingly. The control device estimates the remaining time and uses this feedback to determine the appropriate power limit, creating a closed-loop control system that prevents electrodeposition while optimizing energy recovery.
Data Source
AI summary
In a control device for an electric vehicle, a setting unit sets, as a maximum value of power capable of being charged into the battery, a short time SOP applied during charging in which a charging time is equal to or less than a predetermined time and a long time SOP applied during charging in which the charging time exceeds the predetermined time. A calculation unit calculates a regeneration SOP corresponding to a maximum value of regeneration power from the motor based on the short time SOP and the long time SOP. A control unit controls the regeneration power from the motor in a range equal to or less than the regeneration SOP. The calculation unit gradually changes the regeneration SOP from the short time SOP to the long time SOP in accordance with a duration time of the regeneration power generation.