DC Circuit Breaker Pulse Current Unit for Arc Extinction
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Solution Overview
Problem
Existing DC circuit breakers face challenges in reliably switching direct currents without causing arcing and requiring additional polarity reversal switches, which complicates the switching process and control of direct current flow.
Innovation Solution
A device with a current pulse unit arranged in a bridging branch decoupled from the DC voltage return conductor, using a parallel resonant circuit with a capacitive energy store and inductor, generates a pulse current to extinguish the arc in the controllable switch, allowing the direct current to flow through a bridging branch without changing the circuit topology, and includes a surge arrester to limit voltage drops and dissipate energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC circuit breaker uses conventional switching methods with mechanical switches or additional polarity reversal switches, then it can switch direct currents, but it causes arcing and requires additional components that complicate the switching process and control
Solution Approach 1:
The patent introduces a current pulse unit as an intermediary component that generates a counter-current pulse to extinguish the arc in the controllable switch. This mediator component enables reliable current interruption without requiring complex mechanical switches or additional polarity reversal switches, thus improving switching reliability while maintaining circuit simplicity
Solution Approach 2:
The patent replaces mechanical switches with a controllable switch (semiconductor device) that can be precisely controlled electronically. By using electronic control signals to activate the current pulse unit, the system eliminates the need for mechanical moving parts and complex mechanical switching mechanisms, reducing device complexity while improving reliability
2Ease of operation
If the current pulse unit is connected directly to the DC return conductor, then it can generate pulse current, but it requires additional polarity reversal switches to reset the energy storage device
Solution Approach 1:
The patent connects the current pulse unit in parallel to the controllable switch, creating an equipotential connection that eliminates the need for additional polarity reversal switches. The energy storage device is reset automatically through the parallel resonant circuit formed by the capacitor and inductor, simplifying the control circuit while maintaining ease of operation
Solution Approach 2:
The patent employs a parallel resonant circuit that naturally oscillates periodically after the pulse current is generated. This periodic action automatically resets the energy storage device through the oscillating current flow, eliminating the need for additional active polarity reversal switches and reducing control circuit complexity
3Reliability
If the direct current is switched off by opening the controllable switch, then the arc can be extinguished, but the current divides into two paths requiring additional damping branches
Solution Approach 1:
The patent extracts the damping function from separate damping branches and integrates it into the current pulse unit itself. The parallel resonant circuit with capacitor and inductor serves both as the pulse generation mechanism and as the damping element, eliminating the need for additional damping branches while ensuring reliable arc extinction through the counter-current pulse
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 solution enables reliable switching of direct currents without dividing the current into two paths, reduces the need for additional polarity reversal switches, and provides better control over the switching process and potential reactions, while also using a pre-charging unit to charge the energy store independently of current direction.
Implementation Method 1
a two-pole current pulse unit with a parallel resonant circuit consisting of a capacitive energy storage device and a series circuit connected in parallel thereto, comprising an inductor and a controllable pulse switch
Implementation Method 2
a capacitive energy storage device and a series circuit connected in parallel thereto, comprising an inductor
Implementation Method 3
includes a surge arrester to limit voltage drops and dissipate energy
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a device (20, 201-206) for switching a direct current in a DC voltage line, comprising an operating current branch, which can be inserted serially into a DC voltage conductor of the DC voltage line and which comprises a controllable switch (21), and a two-pole current pulse unit (30), which comprises a parallel circuit consisting of a capacitive energy store (31) and a series circuit that is connected in parallel to the energy store and has an inductor (32) and a controllable pulse switch (33). A pulse current can be generated by switching the pulse switch or the pulse current flows opposite the direct current to be switched and causes a zero current in the controllable switch. The invention is characterized in that the current pulse unit (30) is arranged in a bridging branch (25) which forms a current path parallel to the controllable switch (21) and which is decoupled from an electric potential of a DC voltage return conductor (29) of the DC voltage line. The pulse current flows in a mesh formed by means of the operating current branch and the parallel current path. The invention further relates to a method for switching a direct current in the DC voltage line, wherein the controllable switch is opened dependent on a control command, and the pulse switch is switched such that the pole of the energy store is reversed and the energy store with the reversed pole generates a pulse current which flows opposite the direct current to be switched off and causes a zero current in the controllable switch.