Design Considerations of Bidirectional SiC Based DC Solid-State Power Controller for MEA Systems

The increase in voltage and power levels of more electric aircraft (MEA) necessitates fast and intelligent protection circuits. Due to the advantage of faster response time, no arc during turn-off and higher reliability, solid-state power controllers (SSPCs) are preferred over electro-mechanical switches. This paper reports a SiC based SSPC connected between the DC bus and downstream capacitive loads. An RC assisted gate voltage control method is presented to pre-charge the capacitive load without any inrush current. Experimental results demonstrating charging of 500 µF within 15 ms without hitting the device SOA limit is presented. Also, a thorough design of over-voltage protection circuit of SSPC is included in this paper to protect SSPC against lightening transients and against voltage spike while breaking short-circuit fault current. Series, parallel combinations of Transient Voltage Suppressor (TVS) diodes are connected across SSPC to keep the peak device voltage below its breakdown voltage. Simulation results are reported for validating the design.