DC Switching Device Module with Segmented Current Handling
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Solution Overview
Problem
Existing switching devices for DC voltage networks with inductances require complex and costly semiconductor switching elements and varistors to prevent arcing during current path separation, leading to oversized and expensive components.
Innovation Solution
A switching device with at least two series-connected switching modules, each containing a controllable semiconductor switching element with a series resistor and capacitor, where the discharge current is handled by a separate semiconductor switching element, allowing the load current-carrying element to be dimensioned for load current only, and optionally using a thyristor for cost-effective operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single controllable semiconductor switching element is used to handle both load current and capacitor discharge current, then the switching device structure is simple, but the semiconductor switching element must be oversized to handle the maximum total current of load current and discharge current, increasing cost and size
Solution Approach 1:
The patent divides the current handling function into two separate semiconductor switching elements: one dedicated to load current and another to capacitor discharge current. This segmentation allows each element to be optimally sized for its specific function rather than one element handling all currents, resolving the contradiction between structural simplicity and component oversizing.
2Power
If mechanical switches are used to separate the current path, then the switching device can handle high currents, but arcs occur during switching unless complex protective wiring with multiple semiconductor switching elements and varistors is provided
Solution Approach 1:
The patent replaces mechanical switches with controllable semiconductor switching elements that use electronic control signals to open and close current paths. This substitution eliminates the need for mechanical contacts and arc suppression components like varistors, while maintaining high current handling capability through proper semiconductor device selection and control timing.
3Adaptability or versatility
If two semiconductor switching elements are connected anti-serially for bidirectional operation, then the switching device can handle bidirectional current flow, but voltage-limiting elements such as varistors are still required and increase cost
Solution Approach 1:
The patent extracts and removes the voltage-limiting elements (varistors) from the circuit by using controllable semiconductor switching elements with appropriate clamping circuits that provide voltage protection without requiring expensive varistor components, while maintaining bidirectional operation capability.
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 design reduces component oversizing and costs while maintaining efficient current handling, eliminating the need for expensive varistors and allowing for lower-cost implementation without compromising performance.
Implementation Method 1
a series circuit consisting of a resistor and a capacitor is connected in parallel
Implementation Method 2
The high power loss in the event of a switch-off is not implemented in the semiconductor switching element of the respective switching modules, but predominantly in the resistance of the respective switching modules
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
The invention relates to a switching device (1) for separating a current path (6) of a DC grid, said current path comprising source-side and load-side capacitors (3, 5). The switching device comprises at least two switching modules (10) which are connected in series. Each of the switching modules (10) comprises at least one controllable semiconductor switching element (13) which is connected in parallel to a series circuit consisting of a resistor (14) and a capacitor (15). The switching device (1) according to the invention is characterized in that the resistor (14) is made of a series circuit of two resistors (141, 142) connected together in series, wherein a first end of the series circuit is connected to a first load connection (11) of the controllable semiconductor switching element (13), and a second end of the series circuit is connected to the capacitor (15). Each of the switching modules (10) comprises another controllable semiconductor switching element (16), which is connected between a first node point (143) of the two resistors of the series circuit and a second node point (144) that connects the capacitor (15) to a second load connection (12) of the controllable semiconductor switching element (13).