Physics / mechanism
Solid-state circuit breakers (SSCBs) replace electromechanical contacts with power semiconductor switches—typically SiC MOSFETs, GaN HEMTs, or IGBTs—to interrupt fault currents in microseconds rather than the 10–100 ms of conventional breakers. Interruption relies on gate-controlled channel pinch-off; energy stored in line inductance is dissipated via a transient-voltage-suppression (TVS) clamp or active snubber. Key parameters: trip time (<10 µs for SiC implementations), on-state resistance (contributing conduction losses, typically 1–5 mW·Ω range at ratings), voltage hold-off (currently 1.5–10 kV SiC devices), and I²t withstand. State of the art: 1.2–3.3 kV SiC-based SSCBs at 500–2000 A continuous; bidirectional topologies for DC microgrids. ABB, Eaton, Littelfuse, and startups like Atom Power and Cree/Wolfspeed ecosystem plays are active.
Competitive landscape
Electromechanical MCBs/ACBs remain dominant on cost ($/A protected) and zero conduction loss. Hybrid breakers (mechanical contact + parallel semiconductor for energy absorption) split the difference—faster than pure mechanical, cheaper than pure solid-state. Fuses compete on simplicity at low cost but are non-resettable. Key differentiator is application: SSCBs win where fast fault isolation, remote reconfiguration, or high cycle rate matters (EV charging, shipboard DC, data-center 400 V DC bus).
Companies using
Connected ideas
Sources
Frontier (open questions)
- To be added.