Current Sensor Failure Detection Using Duty Ratio Comparison
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Solution Overview
Problem
The existing fault detecting apparatuses for current detectors are hindered by the need for additional current sensors to detect failures, which inhibits miniaturization.
Innovation Solution
A fault detecting apparatus that uses a switching control unit to control a switch element, a comparing unit to calculate and compare the duty ratio of a control signal with a theoretical value, and a fault detecting unit to identify failures without an additional current sensor, allowing for miniaturization by using the current changing based on switch element on/off operations as a detected value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional current sensor is used to detect current sensor failures, then detection reliability is improved, but device size increases
Solution Approach 1:
The current sensor detects its own failure condition by monitoring whether the detected current value falls within the expected range based on switch element state, eliminating the need for a separate detection sensor
Solution Approach 2:
The system compares the detected current value with the expected current range determined by switch element on/off state and duty ratio, providing feedback to determine sensor failure
2Measurement precision
If multiple current sensors are deployed for redundancy, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The single current sensor performs both primary current detection and self-failure detection functions, eliminating the need for separate sensors for each purpose
Data Source
AI summary
A fault detecting apparatus, to use an output current from a drive circuit as a current value detected by a current sensor, calculates a duty ratio of a control signal to be supplied to the drive circuit to define the duty ratio as a theoretical value of the duty ratio of the control signal. The fault detecting apparatus compares a duty ratio of a control signal actually supplied to the drive circuit with the theoretical value of the duty ratio of the control signal to determine whether the current sensor (fails on the basis of a comparison result.