Vehicle Backup Power Switching for Limp Home Loads
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Solution Overview
Problem
Existing power supply systems for vehicles lack an effective mechanism to ensure continuous power supply to appropriate loads when the main power supply fails, particularly in limp home mode during autonomous driving.
Innovation Solution
A power supply system comprising a first power supply, a second power supply for backup, a measurement unit to monitor the discharge amount of the second power supply, and a control unit to manage the switching of power supply destinations based on the discharge threshold, ensuring continuous power supply to critical loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sub-power supply is designed to provide predefined maximum current for limp home mode, then the backup power capacity is sufficient for autonomous driving, but the power may be insufficient in actual limp home mode operations
Solution Approach 1:
The patent implements dynamic load switching based on discharge amount thresholds. The control unit monitors the discharge amount of the sub-power supply and switches between first loads (autonomous driving loads) and second loads (non-autonomous driving loads) according to predetermined thresholds. This dynamic adjustment allows the system to adapt power distribution to actual conditions, resolving the contradiction between ensuring sufficient backup power and providing flexible power supply for different operational modes.
2Duration of action of moving object
If the system transfers authority from autonomous driving to non-autonomous driving when backup power is insufficient, then power supply sustainability is improved, but control complexity increases
Solution Approach 1:
The patent establishes predetermined discharge amount thresholds before the limp home mode begins. The control unit compares the actual discharge amount against these pre-set thresholds and automatically switches loads accordingly. This preliminary action approach simplifies control by avoiding real-time complex decision-making, while still achieving extended power supply duration through automated load management based on discharge state.
3Ease of operation
If the discharge amount of the sub-power supply is monitored and used to switch loads, then appropriate power distribution is achieved, but measurement and control requirements increase
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the discharge amount of the sub-power supply and adjusts load configuration based on this feedback. The measurement unit provides real-time discharge amount data to the control unit, which then determines whether to supply power to first loads or second loads based on predetermined thresholds. This feedback loop simplifies power distribution management by automating the decision-making process, though it does require measurement and control infrastructure.
Data Source
AI summary
A power supply system mounted on a vehicle includes: a first power supply for supplying power to a load; a second power supply capable of backing up the first power supply; a measurement unit for measuring a discharge amount of the second power supply; and a control unit for controlling a load of a power supply destination of the second power supply, wherein when the first power supply fails, the control unit supplies power of the second power supply to the first load until the discharge amount reaches a predetermined threshold value, and switches the power supply destination of the second power supply to the second load after the discharge amount reaches a predetermined threshold value.