DC-DC Converter Fuse Disconnection Detection via Controller Logic
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Solution Overview
Problem
In green vehicles like electric and hybrid electric vehicles, detecting disconnection of the input fuse of a low-voltage DC-DC converter without adding separate hardware is challenging due to space constraints and increased costs associated with analog circuits used for detection.
Innovation Solution
A method using a controller to compare input voltage with a setting voltage and verify the state of the main relay and input capacitor voltage, diagnosing fuse disconnection without additional hardware by utilizing existing communication networks between controllers to activate warning lamps for driver notification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate analog circuit (sensing circuit or comparator) is added to detect fuse disconnection, then the detection reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The existing controller is made to perform multiple functions: it continues to control the DC-DC converter operation while simultaneously detecting fuse disconnection by monitoring voltage signals. This eliminates the need for separate dedicated detection hardware, resolving the contradiction between detection reliability and device complexity
Solution Approach 2:
The controller uses its own existing voltage sensing capabilities to detect fuse disconnection, making the system self-diagnostic without requiring external or separate detection circuits. The controller monitors the input voltage at its own terminals and compares it against expected values to determine fuse status
2Measurement precision
If a separate analog circuit is added for fuse detection, then the detection precision is improved, but the manufacturing cost increases
Solution Approach 1:
The controller's existing analog-to-digital conversion and voltage monitoring circuits are utilized for dual purposes: normal operation control and fuse disconnection detection. This reuses existing manufacturing components rather than adding new ones, maintaining measurement precision while reducing manufacturing cost
Solution Approach 2:
The detection function is implemented through software logic that copies the voltage comparison function already present in the controller's normal operation mode. The same voltage sensing and comparison mechanisms are used for both control and detection purposes
3Difficulty of detecting and measuring
If additional hardware is added for fuse detection, then the detection capability is improved, but the space requirements increase
Solution Approach 1:
The controller integrates fuse detection functionality into its existing hardware architecture, allowing the same circuit components to serve both control and detection functions. This eliminates the need for separate detection hardware and the associated PCB space requirements
Solution Approach 2:
The fuse detection function is merged with the controller's existing voltage monitoring and control functions. By combining these functions in a single integrated controller rather than using separate components, the overall space requirement is reduced while maintaining full detection capability
Data Source
AI summary
A system and method that compares an input voltage value through the input terminal of the LDC with a setting voltage in an ignition on-state and an on-state of a main relay for connection of a high-voltage battery Then a verification is made whether the main relay is in the on-state and whether the voltage of an input capacitor in an inverter is in a normal voltage range. As a result a diagnosis is made whether the disconnection of the input fuse has occurred in a low-voltage state when the input voltage is no more than the setting voltage and the on-state of the main relay and the state in which the voltage of the input capacitor in the inverter is in the normal voltage range.