Pyrotechnic Phase-Shorting Switch for Electric Machine Discharge
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Solution Overview
Problem
Existing pyrotechnic safety circuits for electric machines are complex and elaborate in design, requiring multiple pyrotechnic switching elements and additional design efforts for voltage equalization between individual phases.
Innovation Solution
A pyrotechnic switching element with at least three electrical connections, each for a phase conductor, uses a bridging element that short-circuits the conductors as a common neutral point, simplifying the design and ensuring stable electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pyrotechnic switching elements are used to discharge three phases of an electric machine, then the safety function is achieved, but the design complexity and elaborateness increases
Solution Approach 1:
The patent merges multiple pyrotechnic switching elements into a single integrated element with multiple electrical connections (at least three). This single element can simultaneously discharge multiple phases of an electric machine, eliminating the need for separate switching elements for each phase and thereby reducing design complexity while maintaining safety functionality.
Solution Approach 2:
The pyrotechnic switching element is designed with multi-functionality to handle multiple phases. The element includes at least three electrical connections for connecting to phase conductors with different phases, allowing one element to perform the safety function across all phases simultaneously, thus reducing the overall number of components needed.
2Reliability
If voltage equalization between individual phases is implemented, then the safety circuit functions correctly, but additional design effort is required
Solution Approach 1:
The patent implements voltage equalization by providing a common connection point that connects all phase conductors together. This common connection point ensures that all phases are at the same potential during discharge, achieving voltage equalization automatically without requiring complex additional design efforts for each phase connection.
3Reliability
If the bridging element creates a common neutral point for phase conductors, then voltage equalization is achieved, but the electrical resistance values must be precisely controlled
Solution Approach 1:
The patent specifies parameter ranges for electrical resistance values (e.g., ≤10 milliohms, or more strictly ≤5 milliohms or 0.1 to 5 milliohms) to ensure proper voltage equalization. By defining acceptable parameter ranges rather than requiring exact values, the design achieves reliability while maintaining practical manufacturability.
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 reduces design complexity and ensures reliable, stable electrical short-circuiting, minimizing neutral point voltage and electrical load, allowing a single pyrotechnic switching element to discharge multiple phase lines effectively.
Implementation Method 1
at least one pyrotechnic charge, and with a bridging element which, in an initial position before ignition of the pyrotechnic charge, is arranged spaced apart from the conductors and, in a bridging position after ignition of the pyrotechnic charge, is in electrical contact with the conductors
Data Source
Figure 1~3
Figure 2~4
Figure 5~6
AI summary
A pyrotechnic switching element (1) is shown. In order to be able to actively short-circuit an electric machine in a stable manner, it is proposed that the pyrotechnic switching element (1) has at least three electrical connections, each for a phase line (L1, L2, L3) with phases offset from each other, and that the bridging element (6) in the bridging position (7b) electrically short-circuits the current conductors (4a, 4b, 4c) as a common neutral point (S) for the phase lines (L1, L2, L3).