Digital Line Protection with Voltage Drop State Retention
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Solution Overview
Problem
Existing line protection methods, such as fuses, face complexity in designing analog circuitry and software models for achieving specific time-current characteristics, leading to inefficiencies in protecting electric lines from excessive current flow.
Innovation Solution
A line protection device comprising a current sensor, digital filter circuit, switch control circuit, and non-volatile memory circuit that senses and digitally filters the electric current, controlling a switch to interrupt current flow based on filtered values, with the non-volatile memory storing the digital filter state to maintain the time-current characteristic during supply voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If analog circuitry is designed to achieve specific fuse characteristics, then the time-current characteristic can be accurately modeled, but the device complexity increases
Solution Approach 1:
The patent replaces analog circuitry with a digital system consisting of a microcontroller and digital filter algorithm. The digital filter implements the fuse characteristic modeling through software rather than complex analog components, significantly reducing device complexity while maintaining accurate time-current characteristic representation.
Solution Approach 2:
The patent changes the implementation approach from fixed analog circuit parameters to programmable digital parameters. The filter characteristics can be adjusted through software configuration, allowing the same hardware to achieve different fuse characteristics by changing digital filter parameters rather than redesigning analog circuits.
2Ease of manufacture
If a software model of a fuse is implemented, then the device can be simplified, but the complexity of the electronic fuse device increases
Solution Approach 1:
The patent uses a digital filter algorithm implemented in software to model the fuse characteristic, replacing what would traditionally require complex analog circuitry. This software-based approach simplifies the hardware while the overall device complexity increases only minimally due to the use of a standard microcontroller.
3Reliability
If digital filtering is used to model fuse characteristics, then the time-current characteristic accuracy is improved, but the processing time increases
Solution Approach 1:
The patent implements a digital filter with adjustable order and complexity. By selecting an appropriate filter order that provides sufficient accuracy without excessive processing, the system achieves the necessary time-current characteristic modeling precision while minimizing processing time impact on the protection response.
Data Source
AI summary
A line protection device includes a current sensor, a digital filter circuit, a switch control circuit, and a non-volatile memory circuit. The current sensor is adapted to a sense a value of electric current through the electric line. The digital filter circuit is adapted to perform digital filtering of the value of electric current. The switch control circuit is adapted to control a switch to interrupt flow of the electric current through the electric line depending on the digitally filtered value of the electric current. The non-volatile memory circuit is adapted to store a state of the digital filter circuit.