Solid-State Circuit Breaker Interlocking for Switch Short Failures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid-state circuit breakers face a failure mode where a short circuit in the semiconductor device prevents the circuit breaker from opening, leading to potential damage to the circuit breaker, the system, and the load.
Innovation Solution
A system comprising a first solid-state circuit breaker and an upstream circuit breaker, where the first circuit breaker detects a failure mode and requests the upstream circuit breaker to interrupt current, allowing the first circuit breaker to open its mechanical contacts when the current drops to a predetermined level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a solid state switch is used to interrupt current, then the circuit breaker size is reduced and interruption speed is improved, but the reliability deteriorates due to short circuit failure mode
Solution Approach 1:
The patent introduces an upstream circuit breaker as an intermediary backup mechanism. When the downstream solid state circuit breaker detects a short circuit failure mode, it sends a request signal to the upstream circuit breaker, which then interrupts current flow to the failed device, enabling safe opening of mechanical contacts.
Solution Approach 2:
The system prepares for potential solid state switch failure by pre-configuring an upstream circuit breaker as a safety backup. The failure mode detection circuit continuously monitors for short circuit conditions, and the coordinated opening mechanism is ready to activate mechanical contacts safely when failure occurs.
2Reliability
If mechanical contacts are added for galvanic isolation, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent combines solid state switching and mechanical contacts in a hybrid architecture. The solid state switch handles normal current interruption while mechanical contacts provide galvanic isolation and fail-safe protection, with both components coordinated through a unified control system that reduces overall complexity.
Solution Approach 2:
The mechanical contacts serve multiple functions: providing galvanic isolation during normal operation and enabling safe opening during solid state switch failure. The upstream circuit breaker also serves dual purposes as both a protective device and a communication node in the failure response system.
3Volume of moving object
If the solid state circuit breaker uses a smaller airgap, then the size is reduced, but the harmful factors increase due to inability to provide galvanic isolation
Solution Approach 1:
Mechanical contacts are introduced as intermediary components that bridge the gap between the reduced airgap and the requirement for galvanic isolation. These contacts physically separate the circuit when needed, providing the isolation function that the smaller airgap alone cannot ensure.
Solution Approach 2:
The mechanical contacts are positioned and configured in advance to provide immediate galvanic isolation when activated. The system prepares the isolation mechanism beforehand, allowing rapid establishment of physical separation when failure conditions occur, without relying on the smaller airgap alone.
Data Source
AI summary
A system includes a first circuit breaker comprising a first solid state switch, first mechanical contacts, and a current sensor structured to sense current flowing through the first circuit breaker, and a second circuit breaker electrically coupled to the first circuit breaker and being structured to interrupt current flowing to the first circuit breaker, wherein the first circuit breaker is structured to transmit, to the second circuit breaker, a request upon detecting a failure mode, and wherein the second circuit breaker is structured to interrupt current flowing to the first circuit breaker in response to receiving the request, and the first circuit breaker is further structured to open the first mechanical contacts when the current flowing through the first circuit breaker drops to a predetermined level.