Switch Failure Detection Using Current Signal Comparison
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Solution Overview
Problem
Existing switch failure detection devices face challenges in accurately determining switch failures due to fluctuating currents, making it difficult to distinguish between proper switch operation and failure, especially when switches cannot turn off or on correctly, which hinders precise failure detection.
Innovation Solution
A switch failure detection device that includes a microcomputer controlling switches on and off to compare initial current detection signals with signals when switches are turned on or off, allowing for accurate failure detection by determining changes in current flow, thereby canceling the influence of zero outputs without needing offset adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset adjustments are performed to improve current detection accuracy, then measurement precision is improved, but assembly time and complexity increase
Solution Approach 1:
The patent stores initial current detection values in memory before normal operation begins. These preliminary measurements are taken when all switches are in a known state, and are later used as reference points for comparing against current readings to detect switch failures, eliminating the need for time-consuming offset adjustments during assembly.
Solution Approach 2:
The system uses its own initial operational state to establish reference values for failure detection. By automatically storing and comparing against these self-generated reference values, the system achieves accurate failure detection without requiring external calibration or adjustment procedures.
2Ease of operation
If all switches are turned off simultaneously for failure detection, then detection simplicity is improved, but detection accuracy deteriorates due to inability to distinguish proper OFF state from failure
Solution Approach 1:
The patent segments the switch group into individually controllable units. Instead of treating all switches as a single group, the control unit can selectively turn off individual switches while keeping others on, allowing precise identification of which specific switch has failed by comparing current readings before and after each individual switch transition.
Solution Approach 2:
The system dynamically changes the state of individual switches during the detection process rather than maintaining a static all-OFF or all-ON state. By sequentially transitioning switches between ON and OFF states and monitoring current changes, the system can dynamically identify failed switches even when multiple switches are present.
Data Source
AI summary
A switch failure detection device includes switches provided on branch paths, current detection units provided on the branch paths, the current detection units being configured to output a current detection signal, a storage unit configured to store an initial value of the current detection signal, the initial value being output from the current detection units, a switch control unit to turn off one of the plurality of switches one by one with at least another one of the plurality of switches being turned on and a first failure detection unit configured to compare the initial value and a value of a first current detection signal output from a corresponding one of the current detection units when the one of the switches is turned off, the first failure detection unit being further configured to detect a first failure of the plurality of switches based on a result of the comparison.