Circuit Breaker Control for Fast Overcurrent Type Differentiation
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Solution Overview
Problem
Current circuit breakers fail to differentiate between types of overcurrents, such as surge, short-circuit, and fault overcurrents, leading to inadequate protection, especially in cases where surge overcurrents are not properly switched off, and existing solutions that use microcontrollers for differentiation are too slow for quick protection.
Innovation Solution
A circuit breaker design that employs a control circuit with comparators to distinguish between overcurrent types by comparing loop current and voltage thresholds, allowing for microsecond-level protection without analyzing waveforms, using a combination of solid-state and mechanical switches for rapid response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ADC combined with MCU is used to observe current features, then the type of overcurrent can be distinguished, but the protection response time exceeds several milliseconds and cannot be realized quickly
Solution Approach 1:
The patent replaces the software-based ADC+MCU system with a hardware-based comparator circuit system. The comparators directly compare current and voltage signals in hardware, eliminating the need for analog-to-digital conversion and microcontroller processing, thus achieving microsecond-level response while maintaining differentiation accuracy
Solution Approach 2:
The patent extracts only the essential comparison function needed for overcurrent type differentiation, removing unnecessary waveform analysis and processing steps. By using comparators to directly compare threshold signals with actual signals, the system achieves fast protection without the overhead of complete waveform processing
2Speed
If simple current threshold comparison is used, then the response is fast, but the type of overcurrent cannot be distinguished and main loop cannot be kept on during surge overcurrent
Solution Approach 1:
The patent adds voltage comparison as another dimension to the traditional current-only comparison. By introducing a second comparator that compares voltage threshold signals with actual voltage signals, the system can differentiate overcurrent types (surge vs. fault) based on the combination of current and voltage states, enabling selective main loop control while maintaining fast response
Solution Approach 2:
The patent segments the protection function into two independent comparator circuits: one for current comparison and one for voltage comparison. Each comparator operates independently and quickly, and their outputs are combined through logic circuits to determine the final switching action, achieving both speed and differentiation accuracy
Data Source
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AI summary
A circuit breaker is disclosed, including: an input side including a first input end (IN1) and a second input end (IN2) for respectively connecting to a first line and a second line of a power supply; an output side including a first output end (OUT1) and a second output end (OUT2) for respectively connecting two ends of an electric load to form a load loop; a switch unit (101) arranged between the input side and the output side for turning on and turning off the load loop; a current detection unit (102) for detecting a loop current of the load loop; a voltage detection unit (103) for detecting a loop voltage between the first line and the second line; a control circuit (104) including at least one comparator, the control circuit is configured for controlling whether to turn off the switch unit according to comparison results.