Circuit Breaker Detection Circuit Noise Filtering
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Solution Overview
Problem
Conventional circuit breaker detecting circuits malfunction due to noise in voltage and current detection signals, particularly harmonic noise, which affects precise detection and operation.
Innovation Solution
A detecting circuit for a circuit breaker that includes a low pass filter to remove high frequency noise, an offset remover to eliminate direct current components, an amplifier to enhance signals, and a comparator to generate a breaking control signal based on Root Mean Square (RMS) and reference voltage comparisons, ensuring accurate detection of alternating current components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a detection sensor directly outputs voltage or current detection signals, then the detection circuit can operate, but the detection precision deteriorates due to noise in the signals
Solution Approach 1:
The patent segments the detection signal processing into multiple stages: raw signal acquisition, noise filtering through RC circuits, offset removal, and RMS calculation. This segmentation allows each stage to address specific aspects of signal quality, progressively eliminating noise interference while preserving measurement precision.
Solution Approach 2:
The patent introduces intermediary processing circuits between the detection sensor and the final comparison stage. These intermediaries include RC filtering circuits that attenuate high-frequency noise, offset removal circuits that eliminate DC components, and RMS calculation circuits that convert noisy instantaneous values into stable effective values, thereby mediating the harmful noise before it affects the final detection result.
2Reliability
If harmonic noise such as switching noise from diodes or transistors is present in the detection signal, then the circuit breaker can operate, but malfunction occurs due to distorted comparison results
Solution Approach 1:
The patent applies preliminary noise filtering and offset removal actions before the detection signal reaches the comparison stage. By pre-processing the signal through RC filtering circuits and offset removal circuits, the system eliminates harmonic noise and distortion beforehand, ensuring that the subsequent comparison operation uses clean, accurate data and prevents malfunction.
Solution Approach 2:
The patent implements a feedback mechanism where the detection signal undergoes iterative processing: initial filtering, offset removal, RMS calculation, and threshold comparison. The system continuously monitors the processed signal and adjusts accordingly, ensuring that harmonic noise does not cause false triggering or malfunction by maintaining reliable operation through continuous signal quality assessment.
3Device complexity
If the peak level of the detection signal is directly compared with reference voltage, then the comparison operation is simple, but the detection accuracy deteriorates due to noise-induced waveform distortion
Solution Approach 1:
The patent transforms the detection parameter from instantaneous peak level to Root Mean Square (RMS) value through a dedicated calculation circuit. This parameter change converts noisy, distorted instantaneous signals into stable effective values that accurately represent the AC component magnitude, thereby improving detection accuracy while maintaining reasonable circuit complexity through standardized RMS calculation techniques.
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 solution enables precise detection of AC components even with noisy signals, minimizing malfunctions and enhancing the operational reliability of the circuit breaker by effectively filtering noise and isolating target frequencies.
Implementation Method 1
a low pass filter to remove high frequency noise
Implementation Method 2
an offset remover to eliminate direct current components
Implementation Method 3
an amplifier to enhance signals
Implementation Method 4
a comparator to generate a breaking control signal based on Root Mean Square (RMS) and reference voltage comparisons
Data Source
Figure 1~3
Figure 4
Figure 5~6
AI summary
The present disclosure relates to a detecting circuit for a circuit breaker (10), comprises: a detection sensor (20) configured to output a detection signal by detecting a voltage or a current on an alternating current electric power circuit; a low pass filter (30) configured to output a signal from the detection sensor after removing a high frequency component from the signal; an offset remover (40) configured to output a signal from the low pass filter after removing a direct current offset from the signal; an amplifier (50) configured to amplify a signal from the offset remover, and to output the signal; and a comparator (100) configured to output a breaking control signal such that the circuit breaker operates to a circuit breaking position, if the detection signal input to the amplifier is equal to or larger than a reference voltage.