Overcurrent Detector Using Time Integral Evaluation
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Solution Overview
Problem
Existing overcurrent and short-circuit detection systems tend to trigger unnecessarily due to transient processes like capacitive inrush currents, leading to unnecessary mains shutdowns, production interruptions, and complex troubleshooting.
Innovation Solution
An overcurrent and short-circuit detector with a current sensor and evaluation unit that records current signals with high time resolution, determines the slew rate of current increases, and analyzes the time integral within a defined period, comparing the resulting pair of values to a boundary condition to reliably distinguish between permissible and impermissible current curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high time resolution current recording is implemented, then detection precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential feature needed for detection - the time integral of the current signal - while discarding unnecessary complex evaluations. By focusing solely on the integral value compared against a threshold, the system achieves accurate detection without requiring sophisticated algorithms or extensive computational resources.
Solution Approach 2:
The patent replaces complex mechanical or computational evaluation systems with a simplified mathematical integration approach. The time-integral evaluation can be efficiently implemented through digital signal processing or analog integration circuits, substituting complex decision-making algorithms with a straightforward mathematical operation.
Data Source
Figure 1~3
AI summary
The invention relates to an overcurrent and/or short circuit detector (1), particularly for a safety switching device (2), having at least one current sensor (3) for picking up a current signal with a definable time resolution in at least one electrical current path (4), and at least one evaluating processor unit (5), wherein the evaluating processor unit (5) is designed to determine a first time of a definable steep rise in the current signal, and to form a time integral of the current values of the current signal from the first time to a second time and, in definable time intervals, particularly substantially continuously, to compare a pair of values, consisting of a specific value of the integral and the associated value of the current signal, with at least one definable limit condition, and in the event that the limit condition is exceeded by the value pair, to output an overcurrent and/or short circuit message to an output (11) of the overcurrent and/or short circuit detector (1).