Dual-Battery EV Control Using SOC-Based Motor Operating Areas
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Solution Overview
Problem
In electric vehicles with dual batteries, imbalances in state of charge (SOC) between batteries can occur, leading to deviations in durability and requiring an efficient operational strategy to manage power supply and charging across different operating areas.
Innovation Solution
A method for controlling dual batteries in electric vehicles by determining operating areas based on the state of charge (SOC) of each battery and adjusting power supply and charging strategies using a controller, including hysteresis adjustments to balance battery usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a single battery is used in an electric vehicle, then the system is simple and cost-effective, but the driving range per charge is insufficient
Solution Approach 1:
The battery system is divided into two separate batteries (first battery and second battery) that can be independently managed and controlled. Each battery can be selectively activated based on driving conditions, allowing the system to extend driving range while maintaining operational simplicity through modular segmentation.
2Duration of action of moving object
If dual batteries are used to extend driving range, then the driving range per charge is improved, but imbalance in battery usage occurs leading to SOC deviation and durability issues
Solution Approach 1:
The controller dynamically adjusts the state of charge (SOC) references for each battery based on real-time operating conditions, battery states, and hysteresis values. This dynamic adjustment ensures balanced usage of both batteries, preventing SOC deviation and extending overall system reliability while maintaining the extended driving range capability.
Solution Approach 2:
The system continuously monitors the SOC of both batteries and uses feedback control to adjust SOC references and hysteresis values. This feedback mechanism ensures that both batteries are used in a balanced manner, preventing one battery from being over-discharged or over-charged, thereby maintaining durability and reliability.
3Reliability
If SOC references are adjusted dynamically based on battery state, then battery usage balance is improved, but control complexity increases
Solution Approach 1:
The controller automatically determines whether to adjust SOC references based on the calculated hysteresis value and current battery states, without requiring external intervention or complex manual tuning. The system self-regulates by comparing the hysteresis value against thresholds and autonomously adjusting SOC references to maintain battery balance, reducing the need for additional control complexity.
Data Source
AI summary
An electric vehicle includes a plurality of wheels, a driving motor configured to supply power to the plurality of wheels, and a controller configured to at least control power supply to the driving motor or charging by the driving motor. The controller is configured to: divide an operating area into a plurality of operating areas for the driving motor based on references determined using states of charge (SOCs) of a first battery and a second battery; determine between one of the first battery and the second battery based on an operating area in which an operating point of the driving motor is disposed among the plurality of operating areas; and control the power supply or the charging by using the determined battery.