Circuit Breaker Microcomputer Current Detection Redundancy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing circuit breakers with microcomputer-based overcurrent tripping devices face issues with erroneous tripping or failure to trip due to microcomputer instability caused by disturbance noise or malfunctions, leading to incorrect current detection.
Innovation Solution
A circuit breaker design that incorporates a first current detecting circuit using a microcomputer and a second current detecting circuit using a power supply CT, with comparison means to determine the microcomputer's operation state, preventing erroneous tripping by detecting abnormal states and ensuring accurate current detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a microcomputer is used to detect overcurrent, then automation and measurement precision are improved, but reliability deteriorates due to microcomputer instability from noise or low voltage
Solution Approach 1:
The patent creates a duplicate current detection path: one through the microcomputer (first current detecting circuit) and another through the power supply CT (second current detecting circuit). By copying the detection function and comparing results, the system identifies when the microcomputer has malfunctioned due to noise or voltage issues, thereby maintaining reliability while preserving automation.
2Device complexity
If a single current detection circuit is used, then device complexity is reduced, but measurement precision deteriorates due to microcomputer malfunction
Solution Approach 1:
The patent implements a redundant detection system where the second current detecting circuit (power supply CT) serves as a backup and verification mechanism for the primary microcomputer-based detection. This copying approach ensures that even if the microcomputer fails, accurate current detection is maintained through the alternative path.
Solution Approach 2:
The comparison means continuously compares outputs from both detection circuits and provides feedback about the microcomputer's operational state. When discrepancies are detected, the system can identify microcomputer malfunction and switch to or rely on the power supply CT readings, ensuring continuous accurate measurement.
3Ease of operation
If the microcomputer operates without monitoring, then ease of operation is maintained, but reliability deteriorates due to undetected runaway states
Solution Approach 1:
The comparison means acts as a continuous monitoring mechanism that automatically compares the microcomputer's current readings with the power supply CT readings. This feedback system detects when the microcomputer enters a runaway state without requiring manual intervention, maintaining ease of operation while significantly improving reliability through automatic anomaly detection.
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
This design effectively prevents erroneous tripping and ensures reliable operation by detecting microcomputer malfunctions and noise interference, maintaining accurate current detection and proper tripping functionality.
Implementation Method 1
a first current detecting circuit which detects a load current in accordance with a signal output from a current detecting coil (2)
Implementation Method 2
a second current detecting circuit which detects a load current using an output current of a power supply CT (1)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A circuit breaker that detects an overcurrent and carries out a triggering includes a first current detecting circuit that detects a load current using a microcomputer in accordance with a signal output by a current detecting coil, a second current detecting circuit that detects a load current using an output current of a power supply CT, and comparison means that compares an output signal of the first current detecting circuit and an output signal of the second current detecting circuit, and determines whether an operation of the microcomputer is normal or abnormal.