Switching Device Semiconductor Arc Suppression
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Solution Overview
Problem
Existing switching devices for high DC and low-frequency AC currents face issues with unwanted switching arcs, leading to reduced functional reliability and shorter electrical service life due to arcing and material migration at contact surfaces.
Innovation Solution
The solution involves designing switching electronics to repeatedly switch the semiconductor switch on and off according to a predetermined sequence during the opening process of mechanical contact arrangements, using an auxiliary coil to generate power for the switching electronics, and employing a current converter to manage current flow and commutation times, thereby extinguishing arcs and ensuring reliable isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the semiconductor switch is kept activated for a longer duration to ensure complete current commutation, then the reliability of current isolation is improved, but the electrical service life of the semiconductor switch deteriorates due to increased stress and heat
Solution Approach 1:
The patent applies periodic action by repeatedly switching the semiconductor switch on and off during the contact opening process. The switching electronics activate the semiconductor switch in multiple phases: first before contact separation, then after separation, and potentially a third time after isolating contact opening. This periodic reactivation ensures complete current commutation while limiting the total duration of semiconductor conduction, thereby balancing isolation reliability with device service life.
2Reliability
If the mechanical contact arrangement is opened quickly to reduce arcing time, then the functional reliability is improved, but the risk of unwanted switching arcs increases due to rapid current commutation
Solution Approach 1:
The patent applies preliminary action by activating the semiconductor switch before the mechanical contacts are fully separated. The switching electronics detect the opening process and activate the semiconductor switch in advance, creating a prepared state that allows immediate current commutation when contacts separate, thereby preventing switching arcs while enabling rapid contact opening.
Solution Approach 2:
The patent applies feedback by using the switching electronics to detect the state of the mechanical contact arrangement and adjust the semiconductor switch activation accordingly. The switching electronics monitor the opening process and trigger semiconductor activation at appropriate moments, creating a closed-loop control system that prevents unwanted arcs while ensuring complete current commutation.
3Duration of action of stationary object
If the semiconductor switch is used to minimize current load time, then the dimensioning and life expectancy are improved, but unwanted switching arcs can still occur under certain circumstances
Solution Approach 1:
The patent applies periodic action by implementing multiple activation phases of the semiconductor switch during the contact opening sequence. This ensures that the semiconductor switch is active at the precise moments when current commutation is needed, minimizing total conduction time while preventing switching arcs through timely reactivation after contact separation and isolating contact opening.
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 approach significantly reduces the risk of unwanted arcs, enhances functional reliability, and extends the electrical service life of switching devices by controlling current flow and commutation times, ensuring effective isolation and minimizing arcing-related damage.
Implementation Method 1
an auxiliary coil 40, which is galvanically isolated from the circuit of a switching drive for moving contacts of the first and second mechanical contact arrangement and is electromagnetically coupled to a coil of the switching drive in such a way that a voltage is generated in it when the voltage supply of the switching drive is switched off
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
The invention relates to a switching device for conducting and interrupting electric currents, comprising a first mechanical contact assembly (10), a semiconductor switch (20), which is connected in parallel with the first mechanical contact assembly, a second mechanical contact assembly (30), which is connected in series with the first mechanical contact assembly, an auxiliary coil (40), which is galvanically isolated from the circuit of a switching drive for moving contacts of the first and second mechanical contact assemblies and is electromagnetically coupled to a coil of the switching drive in such a way that a voltage is produced in the auxiliary coil when the voltage supply of the switching drive is switched off, and switching electronics (50), which are designed to switch the semiconductor switch (20) on and off and which are supplied by the voltage produced in the auxiliary coil when the voltage supply of the switching drive is switched off. According to the invention, the switching electronics (50) are designed to switch the semiconductor switch (20) on and off multiple times according to a predefined sequence during an opening operation of the first and the second mechanical contact assembly (10, 30), in order to interrupt electrical currents.