Switching Apparatus Short Circuit Detection via Wire Resistance
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Solution Overview
Problem
Existing switching apparatuses face challenges in accurately distinguishing between arm short circuits and load short circuits due to the dependency of di/dt magnitude on load state, leading to inconsistent detection results.
Innovation Solution
The proposed switching apparatus incorporates a configuration with two switching devices and an output wiring section, where the wire resistance between the switching devices and the output terminal differs, allowing for the use of current or temperature sensors to detect overcurrents, enabling differentiation between load and arm short circuits based on current flow comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If di/dt magnitude is used to distinguish between arm short circuit and load short circuit, then detection can be performed with simple circuit configuration, but the detection accuracy deteriorates because di/dt magnitude depends on load state
Solution Approach 1:
The invention divides the detection function into two separate detection circuits: one for detecting current through the switching device (first detection circuit) and another for detecting current through the opposing arm (second detection circuit). This segmentation allows independent measurement of current paths, enabling accurate distinction between arm short circuits and load short circuits without being influenced by load state variations.
Solution Approach 2:
The invention introduces wire resistance as an intermediary element with different values in the two current paths. By designing the wire resistance in the first path to be different from the wire resistance in the second path, the system creates a measurable difference that serves as a mediator to identify the type of short circuit occurring, thereby improving detection accuracy.
2Measurement precision
If two types of detecting means are used to distinguish arm short circuit and load short circuit, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The invention uses the same type of detection circuit (current detection) for both detection paths, making the detection means universal. The first detection circuit detects current through the switching device, and the second detection circuit detects current through the opposing arm, both using identical detection methodology. This multi-functional approach maintains detection accuracy while avoiding the complexity of implementing fundamentally different detection mechanisms.
Solution Approach 2:
The invention changes the parameter of wire resistance in the two detection paths to different values. By setting the wire resistance in the first path to be different from the wire resistance in the second path, the system creates a parameter difference that enables accurate short circuit type identification using simple current detection, thereby achieving high detection accuracy without complex detecting means.
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 configuration effectively identifies overcurrents in the output terminal or opposing arm by comparing detection values, improving the accuracy of short circuit differentiation and enabling timely intervention to prevent damage.
Implementation Method 1
a wire resistance between the second main terminal of the first switching device and the output terminal is lower than a wire resistance between the second main terminal of the second switching device and the output terminal
Data Source
AI summary
Provided is a switching apparatus and a determination apparatus connected to the switching apparatus. The switching apparatus comprises: a first switching device and a second switching device, wherein each first main terminal is connected to a first reference potential; an opposing switching device, wherein a second main terminal is connected to a second reference potential; an output wiring section; a first detector for detecting a first detection value changing in accordance with current flowing in the first switching device; and a second detector for detecting a second detection value changing in accordance with current flowing in the second switching device.