Low-Voltage Battery Charging Control via DC Converter Power Monitoring
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Solution Overview
Problem
Existing methods for controlling the charging of low-voltage batteries in fuel cell vehicles fail to accurately determine the state of charge, leading to accelerated discharging and insufficient charging, which can prevent vehicle start-up due to inadequate voltage control.
Innovation Solution
A method and system that determine the state of charge of the low-voltage battery based on the output power of a low-voltage DC converter during vehicle start-up and voltage levels, allowing for precise charging control by setting the charged voltage based on the determined state and driving mode, including adjustments for high-load electric components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage control according to the related art is performed, then the system is simple to operate, but the low-voltage battery may be maintained in a discharged state and the vehicle may not be capable of being started
Solution Approach 1:
The patent changes the parameters used for determining battery state from only voltage to a combination of voltage and consumed power of the low-voltage DC converter. This allows more accurate determination of state of charge and appropriate setting of charged voltage, ensuring reliable vehicle start-up while maintaining reasonable system complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors both the voltage of the low-voltage battery and the consumed power of the low-voltage DC converter during start-up. Based on this feedback, the controller determines the state of charge and adjusts the charged voltage accordingly, preventing the battery from being maintained in a discharged state.
2Reliability
If the charged voltage is set based only on driving mode and high-voltage battery SOC, then the control method is simple, but the low-voltage battery discharging is accelerated and insufficient charging occurs
Solution Approach 1:
The patent introduces additional parameters (consumed power of low-voltage DC converter and accumulation time) to the charging control method. By monitoring these parameters during start-up, the system can determine the state of charge more accurately and set appropriate charged voltage, ensuring sufficient charging while keeping the control method manageable in complexity.
Solution Approach 2:
The patent performs preliminary determination of the low-voltage battery's state of charge by monitoring the consumed power during the start-up period before setting the charged voltage. This preliminary action allows the system to anticipate charging needs and adjust the charged voltage proactively, preventing insufficient charging.
3Measurement precision
If the state of charge is determined only by voltage level, then the determination process is simple, but the state determination is inaccurate leading to inappropriate charging control
Solution Approach 1:
The patent changes the basis for state of charge determination from单一的voltage level to a combination of voltage level and consumed power characteristics during start-up. By analyzing the power consumption pattern and accumulation time, the system achieves more precise state determination, which then guides appropriate charging control decisions.
Solution Approach 2:
The patent adds another dimension (time dimension through accumulation time measurement) to the state of charge determination process. By monitoring how long the consumed power remains in specific ranges during start-up, the system gains more information about the battery state, improving determination accuracy without excessive complexity.
Data Source
AI summary
A system and method for controlling charging of a low-voltage battery are provided. The method includes determining a state of charge of the low-voltage battery of a vehicle based on a voltage of the low-voltage battery and determining a state of charge of the low-voltage battery based on a magnitude of consumed power of a low-voltage direct current (DC) converter (LDC) providing charged power to the low-voltage battery during a period in which vehicle start-up is performed. A charged voltage of the low-voltage battery is then set based on a determination result of the state of charge of the low-voltage battery.