Hybrid Switching Circuit for Arc-Free DC Isolation
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Solution Overview
Problem
Existing switching devices for low-voltage systems, particularly in direct current applications, face challenges with arc suppression, transient leakage currents, and high mechanical stress due to the need for quick switch-off times and isolation distances, which are not adequately addressed in existing technologies.
Innovation Solution
A switching device with a series connection of mechanical and electronic switching elements, where the electronic element controls the current flow and arc extinction during switch-off, and the mechanical element opens the contacts, ensuring synchronized operation across phases and a time-offset neutral conductor switching to reduce arc formation and transient leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical switching elements are used for rapid switch-off in DC systems, then switch-off time is reduced, but arc formation and mechanical stress increase
Solution Approach 1:
The switching function is divided into two segments: electronic switching elements (semiconductors) handle the arc suppression and current interruption, while mechanical switching elements handle the contact opening. This segmentation allows each component to specialize in its optimal function, reducing overall system stress and arc formation.
Solution Approach 2:
The electronic switching element acts as an intermediary between the power circuit and the mechanical switching element. It controls the current flow and arc extinction during switch-off, protecting the mechanical contacts from direct arc exposure and reducing mechanical stress.
2Device complexity
If mechanical switching elements operate alone in AC systems, then device complexity is low, but transient leakage currents cause incorrect tripping
Solution Approach 1:
The electronic switching element is activated in advance of the mechanical switching element during the switch-off process. It begins controlling the current flow and suppressing arcs before the mechanical contacts open, preventing transient leakage currents that would cause incorrect tripping of protective devices.
Solution Approach 2:
The electronic switching element replaces part of the mechanical switching function, particularly the arc suppression and current control tasks. This substitution eliminates the harmful transient leakage currents associated with pure mechanical switching while maintaining the simplicity of the overall device structure.
3Object-affected harmful factors
If electronic switching elements are used alone, then arc suppression is improved, but mechanical isolation distance cannot be achieved
Solution Approach 1:
The patent merges electronic switching elements (for arc suppression) and mechanical switching elements (for isolation) into a single hybrid switching device. This combination allows the system to achieve both excellent arc suppression characteristics and sufficient mechanical isolating gap, resolving the contradiction between these two requirements.
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
This configuration effectively reduces arc formation, avoids incorrect tripping of protective devices, minimizes mechanical stress, and supports efficient switching in direct current systems while maintaining safety and reliability in low-voltage alternating current environments.
Implementation Method 1
the electronic switching elements first make the current flow of all phases synchronously high-resistance
Implementation Method 2
the mechanical switching elements of all phases open the switching contacts
Implementation Method 3
For each phase, a series connection of a mechanical and an electronic switching element is provided
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a switching device for electrical circuits, in particular for switches for low-voltage installations, comprising a series connection of a mechanical switching element, which has switching contacts for separating the electrical circuit, and an electronic switching element, which is made with semiconductors, both of which are connected to a control device, which is designed such that, during a switch-on process, the switching contacts of the mechanical switching element are closed first and then the electronic switching element becomes conductive, and that, during a switch-off process, the electronic switching element first reduces the current flow and then the mechanical switching element opens the switching contacts.