Solid-State Aided Airgap for Fail-Safe DC Circuit Breaking

The patent replaces the mechanical contact-based arc interruption system with a solid-state electronic switching system. The solid-state circuit breaker uses power electronic components (such as IGBTs or MOSFETs) to switch the circuit on and off without mechanical contacts, thereby eliminating arc generation entirely. This substitution resolves the contradiction by removing the source of harmful arcs while maintaining reliable circuit protection in DC systems.

The patent changes the operating parameters of the circuit breaker by introducing controlled voltage and current waveforms through power electronic switching. Instead of relying on natural zero-crossing of AC waveforms, the solid-state system actively controls the switching timing and waveform characteristics to ensure clean interruption of DC current. This parameter control enables reliable arc-free interruption in DC systems.

The patent introduces an auxiliary air gap switch as an intermediary fail-safe mechanism. This mechanical air gap switch is connected in parallel with the solid-state power electronic switch. Under normal operation, the solid-state switch handles switching operations. However, if the power electronics fail in a shorted condition, the air gap switch can be actuated to physically open the circuit, providing a fail-safe interruption path. This intermediary mechanism resolves the contradiction by adding backup protection without affecting normal arc-free operation.

The patent implements a monitoring and control system that detects power electronics failures beforehand or at the moment of failure. The system includes sensors and control logic that monitor the health status of the power electronic components. Upon detecting a shorted condition, the control system activates the air gap switch to open the circuit, preventing potential damage or safety hazards. This prior cushioning approach ensures fail-safe operation while maintaining the benefits of solid-state switching.

The patent replaces bulky mechanical switching mechanisms with compact solid-state power electronic components. Solid-state switches such as IGBTs and MOSFETs can handle high DC voltages (380V, 500V and above) in a much smaller footprint compared to traditional mechanical circuit breakers. This substitution eliminates the need for expensive and bulky mechanical designs while enabling efficient high-voltage DC operation.

The patent utilizes the advantages of solid-state power electronics to operate efficiently at higher DC voltage levels. By controlling the switching parameters and using appropriate voltage-rated solid-state components, the system achieves high efficiency at 380V, 500V and higher DC voltages without requiring proportional increases in size or complexity. The solid-state architecture allows for optimized voltage handling that reduces losses while maintaining compact dimensions.