It is hard to imagine, but even modern aircraft rely on relatively old power switching technology. The electrical distribution unit (EDU) is the first or primary piece of equipment that distributes power on aircraft after it is produced from the generators. Current technologies used in these systems are electromechanical, meaning a piece of conductor physically has to move to make or break connections for power switching. The reason that electromechanical switches are used is they can switch high current with low power drops; however, the problem with electromechanical switches is they often let through too much power when a fault occurs. The solution: produce solid-state power switches that react much faster when a fault takes place.
Earlier this year the Energy/Power/Thermal Division of the Air Force Research Lab’s (AFRL’s) Propulsion Directorate at Wright-Patterson Air Force Base, Ohio, issued a broad agency announcement (BAA) entitled, “Solid State Electrical Distribution Unit.”
A BAA is a technique used by United States government agencies to contract for basic and applied research. The BAA usually calls for the submission of a multi-page proposal exhaustively explaining the technology and why the interested party should receive the money along with qualification information, including resumes, bibliographies, corporate financials, previous contracts won and federal funding received, and your first born (only kidding about that last one).
GE Aviation won this particular contract, to the tune of $7 million, and they plan to use Silicon Carbide (SiC) to produce the proposed ultrafast EDU. GE Aviation engineers have predicted that the switch will be able to perform switching functions as quickly as one millisecond! In addition to the fast switching speed, the system benefits from solid-state power distribution and the ability to add in digital intelligence—an achievement that just isn’t possible with older electromechanical EDUs. GE Aerospace advanced engineering groups in Vandalia, Ohio, and Cheltenham, England, are currently developing a prototype solid-state EDU.
“Solid-state switching is critical to the Smart-Grid concept of intelligent power management, control, and protection,” says Austin Schaffter, vice president of electrical power systems at GE Aviation. “Aircraft electrical power system designs and architectures are rapidly evolving toward higher degrees of both intelligence and fast control.”
Solid-state electrical distribution units made with Silicon Carbide. Sounds pretty geeky to me! I continue to be impressed with the rate at which mil/aero organizations, and the industry technology firms that serve and support them, innovate…no doubt with the aid of electronic design automation and verification tools at the ready.