Pyrotechnic Switching Bridge for Fast Short-Circuit Disconnection
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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 the risk of re-energization of the high-voltage power supply system after a short-circuit event.
Innovation Solution
A switching device with a pyrotechnic propellant charge that rapidly opens the switching bridge by moving a magnet anchor within a guide sleeve, accompanied by a gas jet to extinguish arcs quickly and an arresting device to prevent unintended reconnection, ensuring rapid arc extinction and secure shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an electromagnetic switching drive is used to open the switching contacts, then the switching device can control normal DC currents, but it cannot rapidly disconnect short-circuit currents in the kilo amp range
Solution Approach 1:
The patent introduces a pyrotechnic propellant charge that converts chemical energy into rapid mechanical motion, dynamically changing the contact opening speed from normal electromagnetic actuation to explosive-driven separation. This dynamic transition enables the switching device to handle both normal operation and short-circuit conditions effectively.
Solution Approach 2:
The patent changes the energy parameter from electrical (electromagnetic coil) to chemical (pyrotechnic propellant), creating sufficient force to rapidly separate contacts under short-circuit conditions. This parameter change allows the system to achieve the required contact opening speed for kilo amp range currents.
2Loss of energy
If the contacts are opened quickly to limit arc energy, then damage from arcs is reduced, but the arcs may persist longer if not properly directed toward extinguishing chambers
Solution Approach 1:
The patent incorporates permanent magnetic arc driver arrangements that are pre-positioned to immediately drive arcs toward deionization arc extinguishing chambers upon contact separation. This preliminary positioning ensures arcs are rapidly directed to extinction zones, preventing energy loss while ensuring reliable arc extinction.
Solution Approach 2:
The patent uses permanent magnets as intermediaries to transfer arc energy from the contact gap to the arc extinguishing chambers. These magnets create magnetic fields that guide and accelerate arcs toward deionization zones, effectively mediating the arc extinction process.
3Measurement precision
If a monitoring sensor initiates a switch-off signal to enable early contact opening, then short-circuit detection is improved, but the response time may be insufficient for kilo amp range currents
Solution Approach 1:
The patent replaces the electrical control system (monitoring sensor + control electronics + electromagnetic coil) with a pyrotechnic actuation system. This substitution eliminates signal processing delays and directly converts chemical energy into mechanical motion, achieving ultra-fast response times for short-circuit current disconnection.
4Speed
If the switching device is designed for rapid contact opening, then short-circuit current disconnection is improved, but the device may be unintentionally re-energized before the short-circuit cause is eliminated
Solution Approach 1:
The patent incorporates an arresting device that mechanically locks the switching bridge in the open position after pyrotechnic actuation. This precautionary measure prevents unintended re-energization by physically blocking contact closure, ensuring system safety until the short-circuit cause is eliminated.
Solution Approach 2:
The patent converts the destructive force of the pyrotechnic explosion into a beneficial dual-function system: it both rapidly opens the contacts to disconnect short-circuit currents and activates the arresting device to prevent re-energization. The harmful explosive force becomes a useful safety mechanism.
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 of short-circuit currents, minimizing arc energy and preventing unintentional re-energization of the high-voltage power supply system, ensuring safety and reliability in electric vehicles.
Implementation Method 1
an electromagnetic switching drive with a coil for generating a magnetic field and a magnet anchor
Implementation Method 2
a pyrotechnic propellant charge located in the cavity. 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 3
the current routing in the switching device is designed in such a way that, in such a case, dynamic magnetic blast field forces are generated which superimpose the permanent magnetic field and, after opening the switching contacts, ensure rapid movement of the arcs
Data Source
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AI summary
A switching device (1) for fast disconnection of short-circuit currents comprises a switching bridge (10) and an electromagnetic switching drive (100) with a coil (20) for generating a magnetic field and a magnet anchor (15). The switching device (1) further comprises a guide sleeve (30) to guide the movement of the magnet anchor (15). The magnet anchor (15) is arranged within the guide sleeve (30) such that a cavity (33) is formed below the magnet anchor (15). A pyrotechnic propellant charge (60) is located in the cavity (33). As a result of ignition of the pyrotechnic propellant charge (60) within the cavity (33), the magnet anchor (15) is moved from a first position within the guide sleeve (30) at which the switching bridge (10) is operated in the closed state to a second position at which the switching bridge (10) is operated in the open state.