Low Voltage Battery Charging Control for Fuel Cell Vehicles
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Solution Overview
Problem
In fuel cell vehicles, the continuous discharge of low voltage batteries due to variable voltage control based on driving mode without considering auxiliary machinery power can prevent vehicle startup, as increased auxiliary machinery power leads to excessive battery discharge.
Innovation Solution
A method and apparatus that determine the consumption pattern of auxiliary machinery, set a base charging voltage based on this pattern, and adjust the low voltage battery charging voltage according to the driving mode and high voltage battery state of charge, preventing excessive discharge and ensuring vehicle startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If variable voltage control is performed based on driving mode without considering auxiliary machinery power, then fuel efficiency and system stability are improved, but continuous discharge of the low voltage battery occurs causing potential startup failures
Solution Approach 1:
The patent changes the charging voltage parameter dynamically based on auxiliary machinery power consumption patterns. By categorizing consumption into economy, normal, and excessive modes, the system adjusts charging voltage to prevent battery discharge while maintaining fuel efficiency. This resolves the contradiction by making the voltage parameter adaptive to actual power needs.
Solution Approach 2:
The system implements feedback by continuously monitoring auxiliary machinery power consumption and adjusting the charging voltage accordingly. The controller receives information about power consumption patterns and modifies the charging voltage to prevent battery discharge, ensuring reliable vehicle startup while maintaining energy efficiency.
2Reliability
If charging voltage is increased to prevent battery discharge, then vehicle startup reliability is improved, but fuel efficiency deteriorates due to excessive energy consumption
Solution Approach 1:
Rather than using a fixed high charging voltage, the system dynamically changes the voltage parameter based on actual power consumption patterns. This allows the charging voltage to be increased only when necessary (excessive consumption mode) and reduced when not needed (economy mode), preventing battery discharge while avoiding unnecessary energy waste.
Solution Approach 2:
The system applies partial action by adjusting charging voltage only to the extent necessary to prevent battery discharge. Instead of continuously applying maximum charging voltage, the system applies increased voltage only when power consumption patterns indicate a risk of battery discharge, thereby maintaining reliability while minimizing energy loss.
3Device complexity
If fixed charging voltage is used for the low voltage battery, then system complexity is reduced, but the battery may be overcharged or undercharged leading to performance degradation
Solution Approach 1:
The patent implements parameter changes by adjusting charging voltage based on power consumption patterns (economy, normal, excessive modes) and high voltage battery state of charge. This dynamic adjustment prevents overcharging and undercharging, maintaining battery performance stability while adding only moderate complexity through predefined voltage levels and consumption categorization.
Solution Approach 2:
The system transitions from static fixed voltage to dynamic voltage adjustment based on real-time operating conditions. By making the charging voltage adaptive to power consumption patterns and battery state, the system maintains optimal battery performance without requiring excessively complex control mechanisms.
Data Source
AI summary
A method and an apparatus for controlling charging of a low voltage battery are provided. The method includes determining a consumption pattern of an auxiliary machinery based on a consumed power of the auxiliary machinery and setting a base charged voltage based on the consumption pattern of the auxiliary machinery. Further, a charged voltage is set for the low voltage battery based on the base charged voltage, a driving mode of a vehicle, and a state of charge of a high voltage battery.