SiC MOSFET Based SSCB For Aviation System Applications

Abstract

The Solid-State Circuit Breaker (SSCB) is a critical device for the protection of DC power distribution systems such as those found in renewable energy and aerospace applications. With the development of the DC distribution system at medium voltage levels that are over 1kV and the requirement of the SSCB short circuit performance becomes more critical to protect the network. Therefore, an optimised control system to minimize the overcurrent and short circuit time when the fault occurs for SSCB based on SiC MOSFET is introduced in this thesis. The maximum short circuit survival time is a critical parameter to evaluate the MOSFET short circuit ability. Therefore in this thesis, the maximum short circuit survival time of three different SiC MOSFETs from the same family is estimated from three different experimental circuit characters, including the overcurrent and overvoltage, the Gate state and the safety junction temperature, and used to designed the control system for short circuit test. The shut down time of different MOSFETs is obtained from the short circuit test to evaluates the performance of the control system. The shut down time of MOSFET driven by convex drive signal is the shortest, followed by linear, and the concave drive signal is the longest. Meanwhile, the shut down time decreases with the drive signal drop speed increasing. In addition, the MOSFET with higher on-state resistance has the shorter shut down time. In the future, the high power applications require the higher rated voltage SSCB, therefore, the series or parallel connected MOSFETs are proposed to increase the rated voltage and current of SSCB. To avoid the voltage and current, which are higher than rated values, applied to and flowing through the individual MOSFET to destroy the device, the control system are required to generate the synchronous drive signals to control the MOSFET, which is a challenge for the future drive signals and control system.