Low-Voltage Circuit Breaker Gate Voltage Control
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Solution Overview
Problem
Existing low-voltage protective switching devices face issues with high thermal loading and reduced service life when handling short-circuit currents, leading to potential thermal overload and increased complexity with multiple IGBTs in parallel, which complicates commutation and increases loop inductance.
Innovation Solution
A low-voltage protective switching device using a single power semiconductor component, such as an IGBT or MOSFET, with a control and driver unit that temporarily increases the gate voltage for short-circuit or overcurrent switching, reducing thermal issues and extending service life by minimizing loading time and loop inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple IGBTs are connected in parallel to handle high short-circuit currents, then the current-carrying capacity and thermal overload resistance are improved, but the device complexity and loop inductance increase significantly
Solution Approach 1:
The patent changes the gate voltage parameter dynamically - using a first gate voltage during normal operation and a second, higher gate voltage during short-circuit conditions. This parameter change enables a single IGBT to handle high short-circuit currents that would otherwise require multiple parallel IGBTs, thereby reducing device complexity while maintaining thermal overload resistance.
2Reliability
If multiple IGBTs are connected in parallel to handle high short-circuit currents, then the current-carrying capacity is improved, but the commutation time increases due to increased loop inductance
Solution Approach 1:
The patent applies parameter changes by temporarily increasing the gate voltage to a second value during short-circuit conditions. This enables a single IGBT to sustain high current with lower power loss, achieving the current-carrying capacity of multiple parallel IGBTs while maintaining shorter commutation times due to reduced loop inductance.
3Speed
If the IGBT is constantly switched on to handle short-circuit currents, then the response time is improved, but the power loss increases and the IGBT may be thermally overloaded
Solution Approach 1:
The patent implements preliminary action by pre-charging the gate capacitor to a second, higher voltage value before a short-circuit event occurs. When a short circuit is detected, the IGBT is already in a state ready to handle high currents with minimal power loss, enabling fast response while avoiding thermal overload. The higher gate voltage is maintained only for the brief duration needed to clear the short circuit.
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
Enables safe switching off of high short-circuit currents with reduced power loss and thermal problems, extending the service life of the power semiconductor and reducing loop inductance for quicker commutation, thus enhancing the overall reliability and longevity of the device.
Implementation Method 1
the control and driver unit (13) for this purpose is designed to switch through the first semiconductor circuit arrangement (11) in normal operation of the low-voltage protective switching device (1) with a first voltage value of the control voltage, the first voltage value being lower than a peak control voltage of the power semiconductor, the control and driver unit (13) being designed to increase the control voltage from the first voltage value to a second voltage value in a first step upon detection of a short-circuit current or an overcurrent, which second voltage value is greater than the peak control voltage of the power semiconductor
Implementation Method 2
a first semiconductor circuit arrangement (11) having at least power semiconductors, the low-voltage protective switching device (1) having a control and driver unit (13) for driving the first semiconductor circuit arrangement (11) with a control voltage
Data Source
Figure 1~2
AI summary
In a low-voltage protective switching device (1) with a first external conductor section (2) with a mechanical bypass switch (8), wherein a first semiconductor circuit arrangement (11) of the low-voltage protective switching device (1) is connected in parallel to the bypass switch (8), wherein the first semiconductor circuit arrangement (11) comprises at least one power semiconductor, wherein the low-voltage protective switching device (1) comprises a control and driver unit (13) for controlling the first semiconductor circuit arrangement (11) with a control voltage, wherein the control and driver unit (13) is configured to switch the first semiconductor circuit arrangement (11) through the control voltage in normal operation of the low-voltage protective switching device (1) with a first voltage value which is lower than a peak control voltage of the power semiconductor, it is proposed thatthat the control and driver unit (13) is designed, upon detection of a short-circuit current or an overcurrent, in a first step to increase the control voltage from the first voltage value to a second voltage value, which is greater than the peak control voltage of the power semiconductor, and subsequently, in a second step, to switch off the first semiconductor circuit arrangement (11).