Over-Current Fault Detection Self-Test via Capacitor Simulation
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Solution Overview
Problem
Existing over-current fault detection systems in critical systems like jet engines cannot be tested in the field, leading to undetected faults during normal operation and increased production test costs due to the need for external fault application.
Innovation Solution
An excitation circuit with high-side and low-side switches, a microcontroller, a difference amplifier, a comparator, and a capacitor that allows for self-testing of over-current fault detection by simulating an over-current condition during normal operation, enabling the system to detect and isolate faults without external intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external fault application is used to test over-current fault detection, then fault detection capability can be verified, but testing cannot be performed in the field and production test costs increase
Solution Approach 1:
The system performs preliminary self-diagnosis by simulating an over-current condition through the capacitor discharge mechanism before actual operation, allowing the fault detection circuitry to be tested in advance without external fault application equipment
Solution Approach 2:
The excitation circuit performs self-testing by using its own capacitor to simulate an over-current condition, eliminating the need for external test equipment and enabling field testing without increasing production costs
2Reliability
If external test equipment is used to apply faults, then over-current fault handling can be tested, but overhead and production test costs increase
Solution Approach 1:
The system uses its own internal capacitor to generate the test condition, making the fault simulation self-contained and eliminating external test equipment requirements
Solution Approach 2:
The capacitor serves dual purposes: it functions as a normal circuit component during operation and as a fault simulation device during self-testing, eliminating the need for separate test equipment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables in-field self-testing of over-current fault detection, reducing production costs and ensuring timely detection of faults, thereby preventing equipment damage and reducing the risk of fires or other damage.
Implementation Method 1
a capacitor that allows for self-testing of over-current fault detection by simulating an over-current condition during normal operation
Data Source
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Figure 3A~3D
AI summary
A method for enabling a first switch of an over-current fault detection circuit for normal system operation comprising: a. enabling the first switch for a predefined pulse time in order to provide an input voltage to a capacitor, wherein the predefined pulse time is less than an over-current fault time; b. disabling the first switch for the predefined pulse time; c. determining if voltage of the capacitor is large enough that the first switch can be enabled for greater than the over-current fault time without creating an over-current fault condition; d. repeating steps a and b if the capacitor voltage is not large enough; and e. enabling the first switch for the duration of normal system operation.