Series Switch Assembly Layout for Semiconductor Overvoltage Protection
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Solution Overview
Problem
Semiconductor switches connected in series are vulnerable to overvoltages due to potential defects, which can lead to damage or failure, particularly in power converter modules where voltage is divided among switches.
Innovation Solution
A circuit arrangement with each switch assembly comprising a semiconductor switch, a freewheeling diode, and a surge arrester connected in parallel, where the assembly components are stacked and electrically connected through direct and bridge connections, with surge arresters limiting voltage to prevent overvoltages across semiconductor switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If semiconductor switches are connected in series to handle high voltage, then the voltage handling capability is improved, but the risk of overvoltage damage to individual switches increases due to potential defects
Solution Approach 1:
The patent applies beforehand cushioning by introducing surge arresters and clamping circuits as protective measures before overvoltage damage can occur. These components are pre-configured to activate when voltage exceeds safe thresholds, cushioning the semiconductor switches from overvoltage stress caused by defects or transient conditions in series connections.
Solution Approach 2:
The patent uses surge arresters and clamping circuits as intermediary protective elements between the series-connected semiconductor switches. These intermediaries limit voltage spikes and redirect excess voltage away from the switches, preventing direct overvoltage damage while allowing the series connection to maintain its high voltage handling capability.
2Reliability
If active clamping or passive circuits are added to protect IGBTs from overvoltages, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the protective function into modular components: surge arresters for voltage limiting and clamping circuits for overvoltage protection. Each semiconductor switch is paired with its own protective components, creating independent protection modules that can be individually configured and maintained, reducing overall system complexity compared to a monolithic protection scheme.
Solution Approach 2:
The patent implements local quality by providing tailored protective circuits for each semiconductor switch position in the series connection. Each switch receives customized overvoltage protection based on its specific operational requirements and voltage stress conditions, allowing optimized protection without unnecessarily complicating the entire system with uniform complex protection for all 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
This configuration effectively protects semiconductor switches from overvoltages by limiting voltage between load terminals, preventing damage and ensuring reliable operation in series connections within power converter modules.
Implementation Method 1
The surge arrester of a switch assembly limits a voltage applied to the semiconductor switch, that is, a voltage between the load terminals of the semiconductor switch, to a maximum value in order to prevent an overvoltage at the semiconductor switch.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a circuit arrangement (1) having a plurality of switch assemblies (3) connected in series, each provided with a parallel circuit of three assembly components (5 to 7), wherein a first assembly component is a semiconductor switch (5), a second assembly component is a freewheeling diode (6), and the third assembly component is a surge arrester (7). The assembly components (5 to 7) are arranged one above the other or next to one another as an assembly component stack, wherein the three assembly components (5 to 7) of each switch assembly (3) are arranged in the assembly component stack in a consecutive manner. Each two adjacent assembly components (5 to 7) are electrically connected to one another by a direct connection (9).