Module Development for a High Specific Power Density High-Efficiency Cryogenic Solid-State Circuit Breaker for Electrified Aircraft Propulsion

Solid-state circuit breaker (SSCB) with high efficiency and high gravimetric power density is required for electrified aircraft propulsion (EAP). A cryogenically cooled gallium nitride (GaN) device-based SSCB module is developed for the EAP system to achieve a higher power density than existing SSCBs. The SSCB module is suitable for medium voltage direct current (MVdc) applications and is designed with low-weight modular cold plates. Each module is rated for 750 V, 100 A, and can interrupt a fault current of 1 kA at cryogenic temperature. The SSCB module structure design, thermal interface design, modular cold plate design, and insulation design are discussed. The developed SSCB module prototype achieves a power density of 329 kW/kg and an efficiency of 99.93%. Experimental results of interrupting a fault of 1 kA and insulation test of the SSCB module are provided to validate its operation.