Anti-Serial DC Switch for Polarity-Sensitive Fault Interruption
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Solution Overview
Problem
Current DC switches are complex, expensive, and not short-circuit proof, making them large and heavy, which complicates their integration into energy supply systems, and they lack efficient control mechanisms for managing current polarity changes.
Innovation Solution
A DC switch design utilizing two turn-off semiconductor switches arranged in anti-serial configuration with anti-parallel diodes or reverse-blocking IGGTs, allowing independent current switching regardless of polarity, enabling efficient energy recovery and fault detection without arcing, and integrating a local control device for selective switching based on current polarity and derivative analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DC switches are used to switch direct current, then the switching function is achieved, but the switches become large and heavy, requiring great effort for integration into energy supply systems
Solution Approach 1:
The patent replaces mechanical DC switch components with semiconductor switches (IGBTs or MOSFETs) that perform the same current switching function electronically. This substitution eliminates the need for heavy mechanical arc-extinguishing structures while achieving reliable DC current interruption through semiconductor switching devices arranged in anti-serial configuration.
2Reliability
If conventional DC switches are designed to handle current switching, then the switching capability is provided, but the switches become complex and expensive
Solution Approach 1:
The patent divides the DC switch into two separate semiconductor switches (first and second turn-off semiconductor switches) arranged in anti-serial connection. Each switch handles one current polarity independently, simplifying the design of individual components while providing comprehensive bidirectional current switching capability through their combination.
Solution Approach 2:
The anti-serial arrangement of the two semiconductor switches enables a single DC switch device to handle both positive and negative current polarities, as well as provide short-circuit protection and controlled current interruption in both directions. This multi-functional design eliminates the need for separate switches for different current directions.
3Ease of operation
If a single turn-off semiconductor switch is used with an anti-parallel diode, then current in one direction can be switched off, but current in the opposite direction cannot be independently controlled
Solution Approach 1:
The patent uses an anti-serial arrangement where two semiconductor switches are connected in series but oriented to conduct current in opposite directions. This asymmetric configuration allows each switch to independently control current in its respective polarity direction, enabling bidirectional current control where each direction can be switched off independently while maintaining ease of operation for each polarity.
Data Source
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AI summary
The invention relates to a method for controlling a direct current switch (1), in particular a fault current protection switch or a circuit breaker. The direct current switch (1) has a first semiconductor switch (2a) and a second semiconductor switch (2b) which can be switched off. The first and the second semiconductor switch (2a, 2b) are arranged between a first connection (21) and a second connection (22) such that a current (i) with a first polarity can be conducted through the first semiconductor switch (2a), and a current (i) with the opposite polarity can be conducted through the second semiconductor switch (2b). One of the semiconductor switches (2a, 2b) is switched off depending on a current measurement value. The invention additionally relates to a direct current switch (1) with a first and a second semiconductor switch (2a, 2b) which can be switched off and a local controller (3) for carrying out such a method. The invention additionally relates to a DC voltage system (50) comprising at least one energy source (5) with a DC voltage, to at least one electric load (6) with a DC voltage connection, and to at least one such direct current switch (1).