Switching System for DC Arc Extinction via Resonance
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Solution Overview
Problem
Existing DC switching systems require continuous charging of capacitors for artificial zero-crossings, providing only a single opportunity to extinguish arcs and necessitating a constant power supply.
Innovation Solution
A switching system with a resonance circuit and two switches that alternate between closed and open states, generating a growing current pulse to achieve multiple artificial zero-crossings without continuous charging, allowing for repeated arc extinction opportunities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitor is continuously charged to provide artificial zero-crossings, then arc extinction capability is improved, but energy consumption and device complexity increase
Solution Approach 1:
The patent employs periodic switching of the two switches to generate oscillating current pulses through the resonance circuit. Instead of continuous capacitor charging, the system uses periodic activation where switches alternately connect and disconnect the resonance circuit, creating discrete current pulses that provide multiple artificial zero-crossings only when needed for arc extinction, thereby eliminating continuous energy consumption while maintaining reliability
Solution Approach 2:
The resonance circuit generates its own energy through electromagnetic oscillation between the capacitor and inductor. The capacitor charges and discharges periodically, with the inductor storing and releasing energy to sustain current flow. This self-sustaining oscillation provides multiple artificial zero-crossings without requiring external continuous power supply, allowing the system to serve itself and eliminate the need for continuous external capacitor charging
2Device complexity
If a single artificial zero-crossing is provided, then the system is simpler, but the reliability of current breaking is reduced
Solution Approach 1:
The patent divides the single zero-crossing function into multiple segments by using two switches that generate sequential current pulses. The first switch generates an initial current pulse, and the second switch generates a subsequent pulse with opposite polarity. This segmentation provides multiple artificial zero-crossings (at least two) within a single breaking operation, increasing the probability of successful arc extinction while maintaining relatively simple circuit architecture
Solution Approach 2:
The system prepares multiple artificial zero-crossings in advance within the same breaking operation. By pre-configuring the resonance circuit with both switches capable of generating sequential pulses, the system ensures that if the first artificial zero-crossing fails to extinguish the arc, subsequent pre-prepared zero-crossings are already available to complete the breaking operation, thereby improving reliability without requiring complex additional components
3Reliability
If two switches are used to generate multiple current pulses, then arc extinction reliability is improved, but device complexity increases
Solution Approach 1:
Both switches in the patent serve multiple functions: they act as arc extinction triggers, energy transfer mediators, and control elements. The first switch initiates the breaking operation and generates the first current pulse, while the second switch provides the second pulse with opposite polarity. This multi-functionality allows two switches to achieve reliable arc extinction without requiring additional dedicated components for each function, thereby limiting the increase in device complexity
Solution Approach 2:
The patent combines the functions of multiple zero-crossing generation, energy storage, and switching control into a single integrated resonance circuit with two switches. Rather than having separate systems for each function, the resonance circuit merges the capacitor, inductor, and two switches into one cohesive unit that accomplishes all necessary functions for reliable arc extinction, thereby reducing overall system complexity despite using two switches
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 system effectively extinguishes arcs with multiple opportunities, reducing the need for continuous capacitor charging and enabling more efficient energy use, with potential size and cost reductions in capacitor components.
Implementation Method 1
a resonance circuit connectable across the contact arrangement... enabling current to flow through the resonance circuit... generating a growing current pulse to achieve multiple artificial zero-crossings
Implementation Method 2
The resonance circuit comprises a capacitor which is continually charged by an energy source. The capacitor is charged to obtain a polarity which enables a capacitor discharge current to flow through the contacts
Implementation Method 3
By selecting suitable values of the capacitor and inductance in the resonance circuit, an artificial zero-crossing is obtained
Implementation Method 4
extinguishing an arc between the contacts... the arc generated at the contacts, which enables the arc current to continue to flow after opening of the separation of the contacts
Data Source
Figure 1~2a
Figure 2b~3b
Figure 4~6
AI summary
The present disclosure relates to a switching system (1) for breaking a current, comprising: a contact arrangement (3) having a first terminal (3a) and a second terminal (3b), a resonance circuit (5) connectable across the contact arrangement (3), a first switch (S1) connected to the resonance circuit (5) and to the first terminal (3a), wherein the first switch (S1) is switchable between an open state and a closed state, wherein in the closed state the first switch (S1) is arranged to enable current to flow through the resonance circuit (5) in a first flow direction and into the contact arrangement (3) in a direction opposite to a contact arrangement arc current flow direction, a second switch (S2) connected to the resonance circuit (5) and to the second terminal (3b) of the contact arrangement (3), wherein the second switch (S2) is switchable between an open state and a closed state, wherein in the closed state the second switch is arranged to enable current to flow through the resonance circuit (5) in a second flow direction opposite to the first flow direction, and a control system (7), wherein the control system (7) is arranged to alternatingly first set the first switch (S1), and then the second switch (S2), first in the closed state and then in the open state upon a current breaking operation, until a current pulse, emanating from energy supplied by a contact arrangement arc current, flowing through the resonance circuit (5) and into the contact arrangement (3) reaches an amplitude which is equal to or greater than a magnitude of a contact arrangement arc current. This disclosure also relates to a method of performing a current breaking operation.