Bistable Disconnecting Device for High-Current DC Load Isolation
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Solution Overview
Problem
Existing devices fail to safely and reliably disconnect high-current DC voltage sources from vehicle networks without switching them off, leading to issues like arc ignition, contact erosion, and power losses, especially at high loads above 500 A, where known devices can only perform a single switching operation effectively.
Innovation Solution
A compact, bistable disconnecting device with a switching arrangement featuring cylindrical flat contacts and a bistable relay, protected by semiconductor components and debouncing devices, allows safe and repeated disconnection of loads up to 1500 A with galvanic isolation, and is designed for universal use with splash-proof and impact-resistant features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical switching contacts are used to disconnect the load, then galvanic isolation is established, but the contacts are worn out quickly due to arc ignition
Solution Approach 1:
The patent introduces an intermediary substance (arc quenching medium such as SF6 gas, nitrogen, or carbon dioxide) between the switching contacts to mediate the arc discharge process. This medium absorbs arc energy, cools the plasma, and prevents direct contact erosion while maintaining galvanic isolation during switching operations
Solution Approach 2:
The patent converts the harmful arc effect into a beneficial process by controlling the arc discharge within a specialized chamber filled with arc quenching medium. The arc energy is used to ionize the medium in a controlled manner, creating a conductive path that facilitates current transfer while the medium simultaneously quenches the arc to protect the contacts
2Duration of action of stationary object
If arc enclosure and cooling mechanisms are added to protect mechanical contacts, then contact lifespan is extended, but device complexity increases
Solution Approach 1:
The patent merges the arc enclosure chamber, cooling medium reservoir, and switching contact mechanisms into a single integrated housing structure. The arc quenching medium serves multiple functions simultaneously: it cools the arc, protects contacts, and acts as an insulating barrier, eliminating the need for separate cooling systems and arc chambers
Solution Approach 2:
The switching device is designed with universal components that perform multiple functions: the housing serves as both structural support and arc chamber; the arc quenching medium provides cooling, insulation, and arc suppression; the bistable relay provides both switching and position indication functions
3Speed
If powerful semiconductor switches are used to disconnect the load, then switching speed is improved, but power losses occur during normal operation and galvanic isolation is lost
Solution Approach 1:
The patent replaces traditional mechanical switching contacts with a bistable relay mechanism that uses magnetic fields and spring forces for switching. This mechanical-magnetic system achieves fast switching speeds comparable to semiconductors while maintaining galvanic isolation and eliminating continuous power losses associated with semiconductor switches
4Power
If mechanical switches are designed to handle high currents up to 1500 A, then load switching capability is improved, but arc ignition and contact erosion become more severe
Solution Approach 1:
The patent changes the physical parameters of the switching environment by introducing arc quenching media with specific electrical and thermal properties. The medium's dielectric strength, thermal conductivity, and ionization characteristics are optimized to handle high currents while suppressing arc formation and protecting contacts from erosion
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 device enables reliable, high-current DC load disconnection with reduced power losses and extended switching cycles, ensuring safety and functionality during vehicle operation, while preventing undesirable switching due to incorrect operation or faulty signals.
Implementation Method 1
a bistable relay (50) is provided, in which at least two flat switching contact pairs (55a, 55b and 56a, 56b) can be brought into a contacting or mutually spaced position
Implementation Method 2
the flow of current through the isolating device is switched to be conductive due to an arc forming in the area of the mechanical switch
Implementation Method 3
the air is ionized
Data Source
Figure 1a~1d
Figure 2~3
AI summary
The invention relates to a device for separating a direct-voltage (electrical) system from an energy source or an energy store and to a method for separating a voltage supply or an energy store from a direct-voltage system.