Dual Pyrotechnic Switch Circuit for Aircraft Short-Circuit Isolation
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Solution Overview
Problem
Existing electrical circuits in aircraft face issues with re-supplying short-circuit faults, particularly when the electric charge acts as a generator, leading to potential degradation and requiring additional fast and non-dissipative protection that is difficult to integrate.
Innovation Solution
An electrical circuit design incorporating pyrotechnic switches with initiator elements and mechanical cut-off elements to rapidly isolate the conductive section between the power supply and the electric charge, triggered by an overload current without the need for specific electronics, using pyrotechnic switches positioned in parallel with a main electrical protection element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional electrical protection is added between the distribution harness and the electric charge to prevent re-supply of short-circuit faults, then the reliability of the electrical circuit is improved, but the device complexity and integration difficulty increase
Solution Approach 1:
The patent combines the additional protection function with the existing main electrical protection element by electrically connecting them in parallel. The initiator element of the pyrotechnic switch is connected in parallel with the main protection element, allowing the pyrotechnic switch to act as a supplementary protection without requiring separate integration infrastructure. This merging approach resolves the contradiction by achieving enhanced reliability while minimizing additional complexity.
Solution Approach 2:
The pyrotechnic switch acts as an intermediary protection mechanism between the main electrical protection element and the electric charge. When the main protection element fails to open quickly enough or fails to open at all, the pyrotechnic switch provides a backup failure mode that physically separates the circuit through mechanical cutting of the conductive element. This intermediary approach ensures reliability without requiring complex control systems.
2Reliability
If a fast and non-dissipative protection is implemented to prevent windmilling effect, then the reliability is improved, but the ease of manufacture and integration deteriorates
Solution Approach 1:
The patent replaces complex electronic control systems with a pyrotechnic-based mechanical cutting mechanism. The pyrotechnic switch uses chemical energy to rapidly melt and separate the conductive element, providing a fast, non-dissipative protection that doesn't require sophisticated electronics or complex integration. This substitution resolves the contradiction by achieving fast protection while simplifying manufacture and integration.
Solution Approach 2:
The pyrotechnic switch changes the physical state of the conductive element from solid to liquid/metal vapor through rapid heating, achieving instantaneous circuit separation. This parameter change (temperature and phase) enables ultra-fast protection response without requiring complex mechanical or electronic systems, thereby improving ease of manufacture and integration while maintaining high reliability.
3Speed
If pyrotechnic switches are used to rapidly cut the conductive element, then the speed of fault isolation is improved, but the device complexity increases
Solution Approach 1:
The pyrotechnic switch serves multiple functions: it acts as a fast-acting circuit breaker, a physical separator of the conductive element, and a backup protection mechanism. By integrating these functions into a single device that can be electrically connected in parallel with existing protection elements, the patent achieves high-speed fault isolation without proportionally increasing device complexity. The universal nature of the pyrotechnic switch resolves the contradiction by providing multiple benefits through a single integrated component.
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
Effectively isolates short-circuit faults, preventing re-supply and reducing the risk of windmilling effects, while allowing for easier integration into aircraft due to reduced size and complexity of the protection system.
Implementation Method 1
at least one first pyrotechnic switch provided with at least one first initiator element and at least one first mechanical cut-off element
Implementation Method 2
pyrotechnic switch provided with at least one first initiator element and at least one first mechanical cut-off element which is configured to electrically cut-off
Data Source
AI summary
An electrical circuit of an aircraft including a power supply electrically connected to an electric charge by a conductive element, and a main electrical protection element. The electrical circuit includes a first pyrotechnic switch provided with at least one first initiator element and at least one first mechanical cut-off element, and a second pyrotechnic switch provided with at least one second initiator element and at least one second mechanical cut-off element. The first initiator element and the second initiator element are each electrically positioned in parallel with the at least one main electrical protection element.