Low-Voltage Circuit Breaker Bypass Switch with Multiple Interruptions
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Solution Overview
Problem
Conventional low-voltage protective switching devices face challenges with high stress on contacts and semiconductor circuits due to high current commutation during short-circuit events, leading to reduced service life and increased load on components.
Innovation Solution
A low-voltage protective switching device design featuring a bypass switch with multiple interruptions and a second semiconductor circuit arrangement in series, which reduces commutation time and load on components by allowing current to be switched off more quickly, using power semiconductors with lower internal resistance and smaller size, and optimizing contact design to minimize arc occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bypass switch contacts are made more robust to withstand high current stress, then the reliability improves, but the device size and mass increase
Solution Approach 1:
The bypass switch is divided into multiple independent contact pairs (at least two) instead of using a single robust contact. This segmentation allows the current to be distributed across multiple contacts, reducing the stress on each individual contact while maintaining overall reliability. The multiple contact pairs work in parallel to handle the high current during short-circuit conditions without requiring each contact to be oversized.
2Loss of time
If the contact opening time is reduced to quickly achieve safe contact spacing, then the commutation time decreases, but the mechanical stress on contacts increases
Solution Approach 1:
The switching action is segmented across multiple contact pairs that open in sequence or simultaneously. This allows the total commutation time to be reduced because the current path is broken more quickly through the multiple interruptions, while the mechanical stress on each individual contact is distributed and reduced compared to a single contact bearing the full load.
Solution Approach 2:
The bypass switch provides more than one interruption point in the current path. This excessive action (multiple interruptions instead of one) ensures that the current is completely and quickly commutated to the semiconductor circuit arrangement, achieving safe contact spacing faster while distributing the mechanical stress across multiple contact operations rather than concentrating it in a single contact opening event.
3Reliability
If power semiconductors with higher load capacity are used to withstand high current, then the reliability improves, but the internal resistance and device size increase
Solution Approach 1:
The current handling duty is segmented between the bypass switch with multiple contact pairs and the semiconductor circuit arrangement. The multiple interruptions in the bypass switch reduce the commutation time and the duration of high current exposure for the semiconductors. This allows the use of power semiconductors with lower individual load capacity, which inherently have lower internal resistance and smaller size, while maintaining system reliability through the redundant multiple contact interruptions.
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
The solution extends the service life of components, reduces the risk of arcing, and allows for the use of less robust power semiconductors, resulting in a more reliable and efficient switching process with reduced energy storage and lower risk of overheating.
Implementation Method 1
Multiple arcs with multiple arc voltages are generated as a result of the multiple interruptions in the bypass switch
Data Source
Figure 1~2
AI summary
Disclosed is a low-voltage circuit breaker device (1) comprising an external conductor section (2) and a neutral conductor section (5), wherein a mechanical bypass switch (8) is arranged in the external conductor section (2), a first semiconductor circuit arrangement (11) of the low-voltage circuit breaker device (1) is connected in parallel to the bypass switch (8), and a current measuring arrangement (12) is arranged in the external conductor section (2) and is connected to an electronic control unit (13) of the low-voltage circuit breaker device (1), wherein the electronic control unit (13) is designed to actuate the bypass switch (8) and the first semiconductor circuit arrangement (11) when a given overcurrent, in particular a short-circuit current, is detected by the current measuring arrangement (12). According to the invention, the bypass switch (8) is in the form of a multiple-breaking switch (27), and in the external conductor section (2), a second semiconductor circuit arrangement (14) is connected in series to the bypass switch (8) and in parallel to the first semiconductor circuit arrangement (11).