Redundant Low-Voltage Battery Charging via Starter Generator Backup
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Solution Overview
Problem
In hybrid electric vehicles, the low voltage battery (e.g., 12-volt battery) may not be adequately charged when the high voltage battery's state of charge is low, or when faults occur in charge enabling components such as the DC-DC converter, alternator, or communication bus, leading to potential vehicle operational failures.
Innovation Solution
A system and method that enables charging of the low voltage battery from a starter generator based on detected faults in charge enabling components, disabling the use of the DC-DC converter when faults are present, ensuring continuous charging through a backup supply to maintain vehicle functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the DC-DC converter is used to charge the low voltage battery from the high voltage battery, then charging efficiency is improved, but system reliability deteriorates when faults occur in the DC-DC converter or other charge enabling components
Solution Approach 1:
The system performs preliminary fault detection on the DC-DC converter and other charge enabling components before charging operations. When faults are detected, the system proactively switches to the starter generator as a backup charging source, preventing charging failure before it occurs and ensuring continuous low voltage battery charging capability
Solution Approach 2:
The system prepares a backup charging path through the starter generator in advance. When the primary DC-DC converter path fails, the pre-configured backup path immediately takes over, providing cushioning against charging failure and maintaining system reliability without interruption to vehicle operations
2Reliability
If multiple charge enabling components are used to ensure reliable charging, then system reliability is improved, but device complexity increases
Solution Approach 1:
The starter generator is designed to perform dual functions: serving as the primary starting motor for the engine and as a backup charging source for the low voltage battery. This multi-functionality reduces the need for dedicated backup charging equipment, thereby limiting complexity increase while maintaining reliability through redundant charging capability
3Reliability
If the system continuously monitors for faults in charge enabling components, then reliability is improved, but use of energy increases due to continuous monitoring and switching operations
Solution Approach 1:
The control system implements feedback monitoring of fault status in the DC-DC converter and other charge enabling components. Based on the feedback signal indicating fault presence, the system automatically switches charging sources from the DC-DC converter to the starter generator, ensuring reliable charging while using energy only when necessary for monitoring and switching operations
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
Ensures the low voltage battery remains charged even under fault conditions, allowing the vehicle to operate in a 'limp home' mode, ensuring safe operation and movement to a service location by switching to the starter generator for charging when DC-DC converter failures or other faults occur.
Implementation Method 1
enabling charging of the low voltage battery from a high voltage battery through a DC-DC converter
Implementation Method 2
enabling charging of the low voltage battery from a starter generator based on the fault
Data Source
AI summary
A hybrid vehicle having an engine, a high voltage battery, a low voltage battery and at least one charge enabling component and system for operating the same includes enabling charging of the low voltage battery from a high voltage battery through a DC-DC converter, charging the low voltage battery with the high voltage battery and the at least one charge enabling component comprising at least the DC-DC converter and detecting a fault in the at least one charge enabling component. Based on the fault, the system performs enabling charging of the low voltage battery from a starter generator based on the fault and disabling charging of the low voltage battery from the high voltage battery using the DC-DC converter.