EV Battery Charging Control for Premature Termination
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Solution Overview
Problem
In electric vehicles, external charging may end prematurely when the external power supply is small, leading to incomplete charging of the high voltage battery due to high power consumption by accessories.
Innovation Solution
An electronic control unit is implemented to limit accessory drive and adjust DC/DC converter output when external power is low, ensuring the high voltage battery reaches the target power storage ratio before ending charging, thereby preventing premature termination of charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If accessories are operated with high power consumption during external charging, then the charging speed and user comfort are improved, but the high voltage battery may not reach the target power storage ratio before charging ends prematurely
Solution Approach 1:
The patent dynamically adjusts the power output of DC/DC converters based on real-time monitoring of external power supply capacity and battery charge status. When external power is limited, the system reduces power allocation to accessories and low-voltage systems, thereby ensuring sufficient power for battery charging and preventing premature charging termination.
Solution Approach 2:
The system changes operational parameters (power output levels) of DC/DC converters according to the detected external power supply capacity. By adjusting conversion ratios and power distribution dynamically, the system optimizes power allocation between different consumers to ensure charging completion while maintaining acceptable performance.
2Power
If multiple DC/DC converters operate at full capacity, then the power supply to low voltage systems is sufficient, but the charged electric power of the high voltage battery becomes equal to or less than predetermined electric power
Solution Approach 1:
The patent applies partial action by operating DC/DC converters at reduced capacity when external power is limited. Instead of maintaining full power output to all systems, the system selectively reduces power to non-critical consumers (accessories, low-voltage systems) to ensure sufficient power remains for high-voltage battery charging, accepting partial reduction in overall system performance.
3Productivity
If the charger supplies maximum power from external supply, then charging efficiency is high, but the charged electric power becomes insufficient when external power is small
Solution Approach 1:
The system dynamically changes the power conversion parameters of DC/DC converters based on external power supply capacity. When external power is small, the converters adjust their operation to prioritize battery charging over other power consumers, ensuring that the quantity of charged electric power meets the predetermined threshold even if overall charging efficiency is reduced.
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 solution effectively suppresses the premature end of external charging by reducing power supplied to the low voltage system, ensuring the high voltage battery reaches the target power storage ratio, even when external power is limited.
Implementation Method 1
a first DC/DC converter connected to the high voltage system power line and the low voltage system power line and configured to supply electric power of the high voltage system power line to the low voltage system power line with deboosting a voltage
Data Source
AI summary
A vehicle includes a motor, a high voltage battery, a charger; an accessory; a first DC/DC converter, a second DC/DC converter, and an electronic control unit configured to: end the external charging, when a power storage ratio of the high voltage battery reaches a target ratio or when charged electric power of the high voltage battery becomes equal to or less than predetermined electric power before the power storage ratio of the high voltage battery reaches the target ratio, while external charging for charging the high voltage battery with the charger using electric power from the external power supply is being performed; and limit a drive of the accessory compared to when the electric power from the external power supply is greater than the predetermined electric power, when the electric power from the external power supply is equal to or less than predetermined electric power.