Managing Loads on Aircraft Generators to Prevent Overheat In-Flight

Abstract

On future UAVs it is envisaged that the power requirements of all on-board electrical systems will increase. Whilst, in most flight (mission) situations the installed generation capacity will have adequate capacity to operate the systems, it is possible that during certain abnormal situations the generators on-board may be forced to operate under very high load conditions. The main failure mechanism for a generator is overheating and subsequent disintegration of windings, hence the research problem being addressed here is that of modeling the thermal dynamics of a generator in such a way that the model can be used to predict future temperatures given knowledge of the future mission requirements. The temperature predictions will be used to allow prioratising of the mission actions in order to get the most out of a generator without overheating it.The research presented here summarises the modeling of the generator and formation of the load management system. Results are presented showing the system reallocating loads after a fault during flight, preventing overheat of the generators and successfully completing the mission.

Design of an aircraft generator with radial force control

“…Due to the high speeds and generated heat during the operation IDGs, they have a cooling system. If the cooling system fails, thermally induced interference forces can act on the generator and consequently on the bearings, which can lead to a bearing failure 4 . In addition, during the take-off and landing manoeuvres of the aircraft, gyroscopic forces can act on the generator's shaft.…”

Real-time Prognostics of a Rotary Valve Actuator

“…Failure prognostics specifically deals with the prediction of damage progression, end of useful life (EOL), and remaining useful life (RUL) of a component. Based on these predictions, maintenace can be optimized (Tian, Jin, Wu, & Ding, 2011;Camci, 2009) and/or loads can be reallocated to slow damage progression (Bole et al, 2010;Graham, Dixon, Hubbard, & Harrington, 2014). In cryogenic propellant loading systems (Barber, Johnston, & Daigle, 2013;Zeitlin, Clements, Schaefer, Fawcett, & Brown, 2013), most hardware faults are observed in the valves controlling the flow of propellant (Daigle & Goebel, 2011a), therefore, valve prognostics is a critical technology for safe and efficient cryogenic loading operations.…”