Arc Detection in Aircraft DC Circuits via Frequency Analysis
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Solution Overview
Problem
Conventional circuit breakers fail to effectively detect arc discharges in direct-current (DC) power supply circuits, leading to potential burnout and damage in aircraft due to the high heat and smoke generated, as they rely on overcurrent detection rather than phase or waveform distortions, which are not applicable to DC systems.
Innovation Solution
An arc detecting device that includes a time series data acquisition unit, a basic data generator for frequency analysis using FFT or BPF, a data processor for statistical processing to convert data into evaluation values, and an arc judging unit that compares these values against a threshold to detect arc discharges, utilizing Mahalanobis' distance or scored power spectra for accurate judgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circuit breakers use overcurrent detection to protect DC power supply circuits, then they can detect overcurrent faults, but they cannot detect arc discharges that do not cause overcurrent
Solution Approach 1:
The patent replaces conventional thermal/electromagnetic trip mechanisms with optical detection. A photodetector detects optical radiation (light) emitted during arc discharge, converting optical energy to electrical signals for processing and trip initiation, enabling detection without overcurrent
Solution Approach 2:
The patent introduces optical radiation as an intermediary medium. The arc discharge generates optical radiation that serves as a detectable signal, allowing indirect detection of the arc through its electromagnetic emission rather than direct electrical measurement
2Device complexity
If conventional circuit breakers wait for overcurrent to trip the circuit, then they simplify the detection mechanism, but they allow thermal damage to occur before protection activates
Solution Approach 1:
The patent performs preliminary detection of arc discharge conditions by monitoring optical radiation before the arc generates sufficient heat to cause wiring damage. The system trips the circuit at the first sign of arc-related optical emission, preventing subsequent thermal damage
Solution Approach 2:
The patent replaces thermal-based protection (waiting for heat buildup) with optical-based protection. The photodetector system detects optical radiation from the arc, enabling early detection and immediate tripping before thermal damage occurs
3Reliability
If arc detection systems use complex frequency analysis and statistical processing, then they improve arc detection accuracy in DC circuits, but they increase device complexity
Solution Approach 1:
The patent applies partial frequency analysis by focusing on specific frequency bands where arc discharge emits characteristic radiation. Rather than analyzing the entire spectrum, the system targets relevant frequency ranges, reducing computational complexity while maintaining detection accuracy
Solution Approach 2:
The system uses statistical processing of detected signals with predetermined thresholds to determine arc presence. The feedback mechanism compares processed signal characteristics against known arc discharge patterns, enabling accurate detection through iterative evaluation
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
The device enables early and accurate detection of arc discharges in both DC and AC power supply circuits, preventing burnout and improving the reliability and safety of aircraft by tripping the circuit before thermal damage occurs.
Implementation Method 1
a photodetector for detecting optical radiation resulting from the arc discharge to one another
Data Source
AI summary
An arc detecting device includes a detector for acquiring time series data concerning a characteristic quantity, such as a voltage or a current in a circuit, targeted for detecting an arc; a basic data generator for generating basic data made of a plurality of frequency components, through frequency analysis from the acquired time series data; a data processor for statistically processing the generated basic data, thereby converting the basic data to an evaluation value highly correlative to an occurrence of the arc; and an arc judging unit for judging the occurrence of the arc, if the evaluation value exceeds a predetermined arc judgment threshold value. In this manner, the arc detecting device that is capable of effectively detecting the arc in a direct-current power supply circuit is provided.