Design Analysis of SiC-MOSFET Based Bidirectional SSPC for Aircraft High Voltage DC Distribution Network

Abstract

Research on electric power systems (EPSs) for the aviation industry has recently grown significantly due to the need to reduce global CO2 emissions from transportation. To fulfill the power requirements of a more electric aircraft (MEA), DC power distribution has emerged as a potential solution. However, the progress of DC distribution faces significant difficulties related to system protection. Solidstate power controllers (SSPCs) are being considered in these applications due to their ability to provide fast-tripping mechanisms for system protection. Although SSPCs have been successfully implemented in low voltage DC 28V aircraft networks, their application in high voltage systems (270 V, ±270 V, or higher) presents challenges, such as over-voltage and excessive power loss, particularly for high-power applications. This paper focuses on the development of SSPCs for a 270 V DC system with a current rating of 125 A / 250 A. The paper presents designs for over-voltage suppression and thermal management of the SSPCs. The study also includes a comparative analysis of using a different number of SiC MOSFET modules connected in series and parallel and their effect on the cooling requirements and circuit temperature to assess power losses, power density, weight, and cooling requirements for the SSPCs. A prototype of the proposed SSPC has been built for experimental validation. Results show effective overvoltage suppression to 480 V and quick interruption capabilities with trip currents of 250 A and 375A within time intervals of 160 µs and 300 µs, respectively, for line inductance of 105 µH. The circuit withstands energy up to 22.5 J for a breaking current of 375 A.INDEX TERMS Electric power systems, more electric aircraft, solid-state power controllers, thermal design, SiC MOSFET, DC distribution and cooling requirements.