Ultrafast Sub-mΩ Battery Switching Module Using SiC JFETs for Hybrid Electric Aircraft Propulsion Applications

This paper presents a 750 V/250 A solid-state Liion battery switching module (BSM) using commercial 1200 V SiC JFET modules for hybrid electric aircraft propulsion applications. Comparing to the incumbent mechanical contactor solution, the BSM offers the advantage of ultrafast fault response (µs-level), reduced fault current stress, and significantly improved operation lifetime. The use of ultra-low RDSON SiC JFET power modules leads to a sub-mΩ total on-resistance for the BSM, comparable to that of the mechanical contactor. The total conduction power loss is therefore limited to less than 60 W, allowing for simple passive cooling. The BSM integrates several intelligent functions by adopting a tri-mode operation concept, allowing for a soft-start process to pre-charge the DC link capacitor with a limited charging current. Design redundancy measures are implemented to mitigate single point failure and ensure reliable and safe operation of the aircraft. Considerations related to circuit and physical designs as well as control algorithms are discussed in this paper. Experimental results to validate the design concept are also reported.