Open-Circuit Detection in Switching Structures Using Time-Window Filtering
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Solution Overview
Problem
Existing methods for detecting open circuits in the wiring of switching structures like H-bridges, especially during normal operation, are prone to false detections due to transient phenomena, particularly in high-speed electric motors, which can lead to irreversible damage.
Innovation Solution
A device with continuous current measurement and time counting mechanisms that compares the measured current with a threshold value, delivering anomaly detection information only if the current remains below the threshold for a specified time interval greater than the control signal period, thereby filtering out transient effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous current measurement is used to detect open circuits during normal operation, then detection capability is improved, but false detections increase due to transient phenomena
Solution Approach 1:
The patent applies preliminary action by establishing a time window threshold before making detection decisions. The system pre-defines that current must remain below the threshold for a specific duration (greater than the control signal period) before triggering an open circuit alarm. This preliminary time-based condition filters out transient current drops that occur during normal motor operation, preventing false detections while maintaining reliable open circuit detection capability.
2Productivity
If current threshold comparison is used for anomaly detection, then detection speed is improved, but accuracy decreases due to transient current variations
Solution Approach 1:
The patent enhances detection accuracy by adding a time-duration condition to the threshold comparison. Instead of immediately triggering an anomaly when current drops below the threshold, the system requires the low current state to persist for a predetermined time window (greater than the control signal period). This preliminary time-based verification maintains fast detection response while accurately distinguishing persistent anomalies from transient current variations during motor operation.
Solution Approach 2:
The patent introduces a time window duration as an intermediary parameter between the current threshold comparison and the final anomaly detection decision. This intermediary time-based condition acts as a filter that mediates between the fast threshold comparison and the need for accurate anomaly identification, allowing the system to maintain high detection speed while improving accuracy by excluding transient phenomena.
Data Source
AI summary
A power supply device, including: a switching structure for controlling a continuous current in an inductive load on the basis of at least one control signal of a power switch; and anomaly detection elements, generating at least one item of information about the detection of an anomaly of the open circuit type in the wiring from the load to the switching structure. The anomaly detection elements include: elements for measuring the current flowing in the inductive load; elements for comparing the measured current continuously with a threshold value; and elements for counting a time interval during which the measured current remains continuously below the threshold value, delivering the anomaly detection information if the counted time interval>a reference time interval, which is k times greater than a period of the control signal, where k>1, and if the duty cycle of the control signal>a threshold value.