Pyrotechnic Switching Bridge for Fast Short-Circuit Arc Extinction
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Solution Overview
Problem
Existing switching devices for high DC currents in electric vehicles struggle to rapidly disconnect short-circuit currents, leading to potential damage from high-energy arcs and safety risks due to prolonged arc extinction times.
Innovation Solution
A switching device with a pyrotechnic propellant charge that, upon ignition, rapidly moves a magnet anchor to open the switching bridge, generating a gas jet to extinguish arcs quickly and an arresting device to prevent unintended reconnection, utilizing a pyrotechnic propellant charge to rapidly open the switching bridge and guide gases to extinguish arcs between contact elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electromagnetic switching is used to open contacts, then the switching device can operate reliably under normal conditions, but the arc extinction time is too long during short-circuit events causing damage
Solution Approach 1:
The patent replaces the conventional electromagnetic switching mechanism with a pyrotechnic actuation system. The pyrotechnic charge converts chemical energy to mechanical motion, driving the magnet anchor to rapidly open the contacts and extinguish arcs in milliseconds, far exceeding the speed of electromagnetic actuators alone.
Solution Approach 2:
The patent fundamentally changes the energy conversion parameters by using pyrotechnic combustion (chemical to mechanical energy) instead of electromagnetic induction (electrical to mechanical energy). This parameter change enables ultra-fast contact opening speeds necessary for rapid arc extinction during short-circuits.
2Reliability
If the switching device opens contacts quickly to limit arc energy, then damage is reduced, but the complexity of the switching device increases due to additional pyrotechnic components
Solution Approach 1:
The pyrotechnic actuator serves multiple functions: it rapidly opens contacts during short-circuits, drives the magnet anchor for contact separation, and can be integrated with existing electromagnetic holding mechanisms. This multi-functionality reduces the need for separate emergency opening systems.
Solution Approach 2:
The pyrotechnic charge is nested within the existing electromagnetic actuator housing, with the magnet anchor serving as both the electromagnetic response element and the pyrotechnic drive element. This nested arrangement minimizes additional space requirements and structural complexity.
3Speed
If a pyrotechnic charge is added to rapidly open contacts, then arc extinction speed increases, but the device requires additional components and space
Solution Approach 1:
The pyrotechnic charge is positioned in a radial or axial dimension within the cylindrical actuator housing, utilizing the existing three-dimensional space efficiently. The magnet anchor moves along the central axis while the pyrotechnic charge surrounds it, maximizing space utilization without increasing overall footprint.
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 fast disconnection and extinction of short-circuit arcs, minimizing energy release and preventing unintended reconnection of the high-voltage power supply, ensuring safety by reducing the time from short-circuit occurrence to arc extinction.
Implementation Method 1
a pyrotechnic propellant charge located in the cavity, a supporting device for supporting the guide sleeve, wherein the guide sleeve and the magnet anchor and the pyrotechnic propellant charge interact such that, as a result of ignition of the pyrotechnic propellant charge within the cavity, the magnet anchor is moved
Implementation Method 2
an electromagnetic switching drive with a coil for generating a magnetic field and a magnet anchor
Implementation Method 3
the magnet anchor being arranged within the guide sleeve such that a cavity is formed below the magnet anchor
Implementation Method 4
the gap is configured to guide a gas flow of gases produced during ignition of the pyrotechnic propellant charge and emerging from the cavity into the gap
Data Source
AI summary
A switching device for fast disconnection of short-circuit currents includes a switching bridge with a movable contacting element and a fixed contacting element. The switching bridge is operable in a closed state, in which the movable contacting element is in contact with the fixed contacting element, and an open state, in which the movable contacting element is spaced apart from the fixed contacting element. The switching device further includes an electromagnetic switching drive with a coil for generating a magnetic field and a magnet anchor, a guide sleeve to guide the movement of the magnet anchor in the magnetic field of the coil, a pyrotechnic propellant charge located in the cavity, and a supporting device for supporting the guide sleeve. The magnet anchor is arranged within the guide sleeve such that a cavity is formed below the magnet anchor.