DC Switch Precharging Circuit for Parasitic Capacitance Spikes
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Solution Overview
Problem
Existing DC switching devices experience current spikes during the switching-on process due to parasitic capacitances, leading to increased wear and potential destruction of electromechanical switches, which is detrimental to their service life.
Innovation Solution
A DC switching device with a pre-charging branch comprising a series connection of a controllable switching element and a current-limiting device, which charges parasitic capacitances in a current-limited mode before closing electromechanical switches, preventing current spikes and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second electromechanical switch is closed during the switching-on process, then the DC load can be electrically connected to the DC voltage source, but a current peak occurs due to discharged parasitic capacitances, leading to increased wear and potential destruction of the electromechanical switch
Solution Approach 1:
The patent applies preliminary action by introducing a pre-charging circuit that charges the parasitic capacitances of the semiconductor switching element before the electromechanical switches are closed. This pre-charging process ensures that when the second electromechanical switch closes, no current peak occurs because the capacitances are already charged to the input voltage level. The control unit coordinates this by activating the pre-charging circuit prior to closing the electromechanical switches, thereby eliminating the harmful current surge that would otherwise damage the switch.
2Productivity
If a pre-charging circuit is activated to charge capacitors on the output side, then the switching-on process can be optimized, but the complexity of the switching device increases
Solution Approach 1:
The patent applies universality by designing the pre-charging circuit to serve multiple functions: it charges the parasitic capacitances of the semiconductor switching element and simultaneously charges the capacitors on the output side during the switching-on process. This multi-functional approach optimizes the switching-on process while minimizing the increase in device complexity, as a single pre-charging circuit accomplishes what would otherwise require separate circuits.
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 effectively prevents current spikes, thereby extending the service life of electromechanical switches and reducing wear, ensuring a longer operational lifespan.
Implementation Method 1
parasitic capacitances that are generally discharged at the beginning of the switch-on process
Implementation Method 2
a first pre-charging branch, which comprises a series connection of a second controllable switching element and a first current-limiting device
Data Source
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AI summary
The present invention relates to a DC voltage switching device (100) for coupling, more particularly for switching on a DC voltage load (200), which comprises a first and a second input terminal (IN+, IN-) which are designed to apply an external DC voltage, a first and a second output terminal (OUT+, OUT-) which are designed to electrically connect a DC voltage load (200), a positive conductor (8) which runs between the first input terminal (IN+) and the first output terminal (OUT+), a negative conductor (10) which runs between the second input terminal (IN-) and the second output terminal (OUT-), a first semiconductor-based, controllable switching element (101, 101') which is arranged in the positive conductor (8) or in the negative conductor (10), an electromechanical switch (108) arranged in the positive conductor (8), an electromechanical switch (110) arranged in the negative conductor (10), and a first precharging branch (120) comprising a series circuit of a second controllable switching element (123) and a first current limiting device (124), wherein the first precharging branch (120) is arranged between the positive conductor (8) and the negative conductor (10).