DC Voltage Switch Polarity Reversal for Rapid Cycling
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Solution Overview
Problem
Existing devices for switching direct currents in a DC voltage network are unable to perform a new switching process shortly after the initial switch-off, as the capacitor is left with an inverse polarity, preventing immediate reuse.
Innovation Solution
Incorporating a polarity reversal branch with a controllable power semiconductor switch that reverses the capacitor's polarity, allowing for immediate reuse by ensuring the pulsed power semiconductor switch is in its blocking position, and using additional inductances and resistances to manage current and voltage effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a capacitor is used to generate a counter current for switching off DC current, then the switching capability is improved, but the capacitor remains charged with inverse polarity preventing subsequent switching operations
Solution Approach 1:
The patent changes the polarity parameter of the capacitor by introducing a polarity reversal power semiconductor switch. After the capacitor C1 is charged with inverse polarity during the switching process, the polarity reversal switch TZ1 is triggered to reverse the capacitor's polarity, restoring it to its original state and enabling subsequent switching operations. This parameter transformation resolves the contradiction by making the capacitor reusable immediately after switching.
2Reliability
If the capacitor is charged to the limiting voltage of the arrester during switch-off, then the switch-off capability is improved, but the capacitor cannot be reused without polarity reversal
Solution Approach 1:
The patent applies preliminary action by preparing the capacitor for the next switching operation immediately after the current switching is completed. The polarity reversal power semiconductor switch TZ1 is triggered right after the switch-off process, reversing the capacitor's polarity before the next switching cycle begins. This preliminary reversal action eliminates the waiting time that would otherwise be required for the capacitor to be ready for reuse.
Solution Approach 2:
The patent ensures continuity of useful action by making the switching process immediately repeatable. Through the polarity reversal mechanism, the capacitor is continuously prepared for the next switching operation without interruption or downtime. The system maintains a continuous cycle of switching and polarity reversal, maximizing the productivity and utilization of the switching device.
3Reliability
If a pulsed power semiconductor switch is used to generate a current pulse for arc extinction, then the arc extinction capability is improved, but the capacitor polarity must be reversed before next use
Solution Approach 1:
The patent merges the polarity reversal function with the existing capacitor path by introducing a polarity reversal power semiconductor switch TZ1 that is connected in parallel with the series connection of capacitor C1 and inductance L1. This merging approach allows the polarity reversal operation to share the same circuit path and components, minimizing additional complexity while achieving the desired functionality.
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
Enables an infinite number of successive switching operations without damage to components, as the capacitor can be reset to its original polarity, allowing for rapid and repeated switching.
Implementation Method 1
The capacitor C1 discharges. In this case, a circulating current is generated in a mesh formed from the capacitor path 6 and the operating current path 4, which is opposite to the operating current I in the mechanical switch 5.
Implementation Method 2
The inductance L1 serves to limit the rise in current when the capacitor C1 is discharged.
Implementation Method 3
From this point in time, the current only flows via arrester 7, which builds up a switch-off reverse voltage that finally switches off the operating direct current I.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
In order to provide an apparatus (1) for switching direct currents in one terminal of a DC voltage grid comprising two connection terminals (2, 3) for introducing, in series, the apparatus (1) into the terminal, an operating current path (4) which extends between the connection terminals (2, 3) and in which a mechanical switch (5) is arranged, a capacitor branch (6) which bypasses the mechanical switch (5) and in which a capacitor C1 is arranged, a pulse-controlled power semiconductor switch Τ1, which is arranged in series with a capacitor C1, for discharging the capacitor C1 so that a pulse circulating current, in the opposite direction to the operating current I in the mechanical switch (5), flows in a mesh formed from the operating current path (4) and the capacitor branch (6), with which apparatus, even after a short period of time, a renewed switching operation can be implemented, it is proposed that a polarity reversal branch (9) is provided which bypasses the capacitor C1 and in which a drivable polarity reversal power semiconductor TZ1 is arranged.