Redundant DC Solid-State Circuit Breaker for Arc-Free Fail-Safe Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing DC circuit breakers face challenges in effectively extinguishing arcs due to the absence of natural zero crossing in DC systems, rendering air gaps ineffective for fail-safe mechanisms, and existing solid-state circuit breakers lack redundancy for reliable operation in DC systems.
Innovation Solution
A DC solid-state circuit breaker design with redundant power electronics switching modules and overvoltage protection devices, featuring an air gap and sensing and control circuit to ensure fail-safe operation, and additional overvoltage protection for surge and load-side protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If air gap is used in DC solid-state circuit breaker for isolation, then switching process becomes arc-free, but fail-safe mechanism is lost when power electronics fail in shorted conditions
Solution Approach 1:
The circuit breaker is segmented into multiple independent power electronics switching modules (first and second modules) with an air gap positioned between them. This segmentation allows the system to maintain arc-free switching while creating redundant isolation points. If one power electronics module fails in a shorted condition, the air gap provides a physical break that prevents arc formation, thereby maintaining fail-safe functionality.
Solution Approach 2:
The air gap acts as an intermediary element between the first and second power electronics switching modules. It serves as a passive isolation component that can interrupt current flow without generating arcs in DC systems, providing a fail-safe mechanism that complements the active power electronics components.
2Reliability
If single power electronics switching module is used, then device complexity is reduced, but reliability under component failure is insufficient
Solution Approach 1:
The circuit breaker incorporates a second power electronics switching module as a backup before failure can occur. This redundant module is positioned in series with the first module and separated by an air gap. If the first module fails, the second module can continue to provide switching functionality, and the air gap ensures that any failure does not result in uncontrolled arcing, thus cushioning against the impact of component failure.
3Reliability
If overvoltage protection devices are used with threshold voltages higher than system voltage, then false triggering is prevented, but protection effectiveness during surges is reduced
Solution Approach 1:
Different overvoltage protection devices are positioned at different locations in the circuit with different threshold voltage characteristics. The first overvoltage protection device is connected in series with the power electronics modules and has a threshold higher than the system voltage to prevent false triggering during normal operation. The second overvoltage protection device is connected across the load and can have a lower threshold to provide effective protection during surge conditions. This local differentiation of protection characteristics allows the system to prevent false triggering while maintaining effectiveness during actual surges.
Data Source
AI summary
A DC solid-state circuit breaker is provided with fail-safe redundancy. The DC solid-state circuit breaker comprises an air gap disposed in series to first and second power electronics switching modules. The DC solid-state circuit breaker further comprises a sensing and control circuit configured to realize designed functions. The DC solid-state circuit breaker further comprises first and second overvoltage protection devices connected in series for overvoltage or surge protection for the sensing and control circuit such that both the first and second overvoltage protection devices have threshold voltages higher than a system voltage. The DC solid-state circuit breaker further comprises a load side overvoltage protection device provided for overvoltage protection after switching OFF.