DC Arc Detection Circuit Using Dual-Domain Signal Analysis
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Solution Overview
Problem
Existing circuits for arc detection in direct current systems suffer from low accuracy due to environmental factors like changes in sun radiation and temperature, leading to false positives and frequent device shutdowns.
Innovation Solution
A circuit comprising a current sampling circuit, a first circuit for processing the signal into a time domain signal with pulses indicating change rate, and a second circuit for amplifying and filtering to produce a frequency domain signal, with a microprocessor analyzing both to count arc events and determine the presence of arcs based on preset conditions, thereby distinguishing between arc changes and environmental changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the microprocessor performs frequency domain analysis and time domain analysis on the direct current signal to detect arcs, then arc detection capability is provided, but environmental factors such as sun radiation and temperature changes cause false positives reducing detection accuracy
Solution Approach 1:
The patent segments the arc detection process into two independent analysis paths: frequency domain analysis (using FFT to detect characteristic frequencies of arcs) and time domain analysis (detecting rapid current changes). By dividing the detection function into separate modules, the system can independently validate arc characteristics in both domains before confirming an arc event, thereby reducing false positives caused by environmental factors affecting only one domain.
Solution Approach 2:
The patent implements a feedback mechanism where the microprocessor continuously monitors both frequency and time domain signals, and only declares an arc event when both analysis paths simultaneously detect arc characteristics. This cross-validation feedback loop filters out false alarms caused by environmental variations, as such variations typically affect only one domain and cannot trigger both detection paths simultaneously.
2Device complexity
If the detection circuit uses simple current sampling and single-domain analysis, then device complexity is reduced, but detection accuracy decreases due to inability to distinguish arc characteristics from environmental changes
Solution Approach 1:
The patent transitions from single-domain analysis to dual-domain analysis by adding frequency domain processing dimension. The system performs both time domain analysis (current change rate detection) and frequency domain analysis (FFT-based characteristic frequency detection), creating a two-dimensional detection space. This dimensional expansion enables precise discrimination between arc events and environmental disturbances without significantly increasing hardware complexity.
Solution Approach 2:
The patent replaces complex hardware-based arc detection mechanisms with software-based signal processing algorithms. Instead of using specialized hardware circuits for arc detection, the system uses a microprocessor to perform FFT transformation and time domain analysis on sampled current signals. This substitution achieves high detection precision while maintaining relatively simple device structure through software intelligence.
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AI summary
A circuit for arc detection in a direct current and a microprocessor are provided, so as to resolve a problem of low accuracy of a detection result of an existing circuit for arc detection in a direct current. The circuit includes a current sampling circuit, a first circuit, a second circuit, and a microprocessor. The current sampling circuit is configured to perform current sampling on the direct current, and output a current sampling signal of the direct current. The first circuit is configured to receive and process the current sampling signal, and output a time domain signal including at least one pulse, where the at least one pulse is used to indicate a time domain change rate of the current sampling signal. The second circuit is configured to receive the current sampling signal, and output a frequency domain signal of the current sampling signal after amplifying and filtering the current sampling signal. The microprocessor is configured to: receive the time domain signal and the frequency domain signal; count a quantity of arc events based on results of analysis on the time domain signal and the frequency domain signal; and when a counting result of the quantity of arc events meets a preset condition, determine that an arc exists in the direct current.