Electric Vehicle Current Limiting for Extended Range
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Solution Overview
Problem
Standard electric vehicles cannot be driven when the battery voltage decreases to a predetermined level, triggering under voltage protection (UVP) mode, limiting their maximum drivable distance due to uncontrolled current output.
Innovation Solution
A system that includes a remaining battery capacity calculator, a controller to limit the output current to a predetermined value, a navigation unit to determine nearby charging stations, and a display unit to inform the driver, ensuring the electric vehicle can travel the maximum distance by optimizing current output based on battery capacity, route conditions, and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery voltage decreases to a predetermined level, then under voltage protection mode is activated, but the electric vehicle cannot be driven
Solution Approach 1:
The system dynamically adjusts the current limit based on remaining battery capacity. When battery voltage decreases, the controller automatically reduces the current limit to extend driving distance, transforming the static UVP threshold into a dynamic control parameter that adapts to battery state
Solution Approach 2:
The controller changes the current limit parameter from its normal value to a reduced value when remaining battery capacity falls below a threshold. This parameter change allows the vehicle to operate in a restricted mode that extends range while preventing complete battery depletion
2Ease of operation
If uncontrolled current output is used, then the electric vehicle can operate freely, but the maximum drivable distance is limited
Solution Approach 1:
The system continuously monitors remaining battery capacity and provides feedback to the controller. Based on this feedback, the controller adjusts the current limit in real-time, creating a closed-loop control system that optimizes drivable distance while maintaining operational freedom within safe boundaries
Solution Approach 2:
The system calculates remaining battery capacity in advance and determines the appropriate current limit before the battery reaches critical low voltage levels. This preliminary action prevents complete battery depletion while maximizing the usable driving distance
Data Source
AI summary
A system for controlling driving of an electric vehicle including a motor and a method of the same are disclosed. In one aspect, the system includes a battery configured to output a driving current to the motor and a battery capacity calculator configured to determine the remaining battery capacity of the battery. The system also includes a controller configured to limit the driving current to a predetermined current limit value or less when the remaining battery capacity reaches a first predetermined value.