Modified O-Z-Source DC Circuit Breaker for Electrical Power System Protection of Future Aircrafts

The increasing population and improved human quality of life bring new challenges to the aircraft industry in terms of increased greenhouse gas emissions as a result of increased air travel. To bring down the carbon footprint of the aviation sector, it is high time to advance toward electrifying air transportation. Consequently, electrification instigates the complex electric power systems (EPS), that adopt low-voltage dc architecture at higher currents to handle high power demands. As the aircraft EPS results in hybrid microgrid demands for a faster protection system for fault interruptions. Among the three main classifications of dc circuit breakers (DCCB), solid-state circuit breakers (SSCB) provide faster fault isolation. SSCBs can aid in achieving less weight and small form factor flight-weight electric components that are competent with high power requirements. This article proposes a modified O-Z-source DCCB (MOZSCB) topology containing a thyristor as the main fault interrupting switch and a coupled inductor helping the commutation of the thyristor. The proposed topology is engaged with fewer components owing to lessening the weight/volume of the aircraft system and can interrupt the fault within 400μs. Also, the proposed topology is designed to overcome the drawbacks of previously reported conventional O-Z-source DCCB, such as negative current flow through the load during reclosing and unwanted power flow while it's commissioning. The proposed topology also mitigates the issues of high current stress on the thyristor while reclosing. To validate the performance of the proposed MOZSCB, a laboratory prototype has been built with a system rating of 270V/10A.