Electronic Circuit Breaker Dynamic Current Limiting for Capacitive Loads
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Solution Overview
Problem
Electronic circuit breakers with semiconductor switches face challenges in efficiently managing capacitive loads, leading to increased costs and space requirements due to oversized MOSFETs, which can result in unreliable operation and failure to switch on loads reliably when capacitive loads are connected, causing output voltage drops and potential short-circuit-like conditions.
Innovation Solution
A method for operating electronic circuit breakers that compares the output voltage with a stored threshold value, gradually increasing and then reducing the current limit value in steps to manage capacitive loads, ensuring the circuit breaker only trips if the voltage threshold is not reached, thereby preventing unnecessary tripping and maintaining reliable load operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the semiconductor switch is oversized to handle power dissipation during capacitive load switching, then the power dissipation capability is improved, but the cost and space requirement increase
Solution Approach 1:
The circuit breaker implements dynamic current limiting that adjusts the current threshold based on the switching state. During capacitive load switching, a higher current threshold is temporarily allowed, while during normal operation the standard threshold applies. This dynamic adaptation eliminates the need for oversized semiconductor switches designed for worst-case continuous power dissipation.
Solution Approach 2:
The invention changes the operating parameters of the semiconductor switch by implementing time-dependent and state-dependent current limiting. The current threshold parameter is modified based on whether the system is in a switching transient or steady-state operation, allowing optimal performance without requiring excessive component margins.
2Power
If the semiconductor switch is oversized to handle power dissipation during capacitive load switching, then the power dissipation capability is improved, but the cost increases
Solution Approach 1:
The circuit breaker implements dynamic current limiting that adjusts the current threshold based on the switching state. During capacitive load switching, a higher current threshold is temporarily allowed, while during normal operation the standard threshold applies. This dynamic adaptation eliminates the need for oversized semiconductor switches designed for worst-case continuous power dissipation.
Solution Approach 2:
The invention changes the operating parameters of the semiconductor switch by implementing time-dependent and state-dependent current limiting. The current threshold parameter is modified based on whether the system is in a switching transient or steady-state operation, allowing optimal performance without requiring excessive component margins.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method for operating an electronic circuit breaker (2) with a semiconductor switch (8) connected between a voltage input (12) and a load output (14), which is controlled when the circuit breaker is switched on and/or when a capacitive load (6) is connected, depending on the output voltage (Va) detected at the load output (14), wherein the output voltage (Va) is compared with a stored voltage threshold (Vs), wherein, when the voltage threshold (Vs) is reached or fallen below, a current limit (Ig), to which a load current (IL) supplied by the semiconductor switch (8) is limited, is set from a nominal value (IN) to a first step value (Is1) higher than this, wherein the current limit (Ig) is reduced stepwise from the first step value (Is1) to the original nominal value (IN), and wherein the semiconductor switch (8) is opened.if the output voltage (Va) does not reach the voltage threshold (Vs) during a tripping time (Ta) after the stepwise reduction of the current limit (Ig).