Intelligent electrical systems will play a key role in greener aircraft
Cruise control in cars has given drivers an improved experience. A shift from conventional hydraulic, mechanical, pneumatic systems to electrically intensive systems in aircraft creates opportunities to introduce similar intelligence to onboard systems. The potential goes way beyond cruise control: it can be used to make future aircraft more fuel efficient - reducing carbon emissions – at the same time as making them more reliable and safer.
This has been a key focus of our work here within the Clean Sky 2 Enhanced electrical energy Management (ENIGMA) project.
Working in tandem with our international partners and leaders in aerospace we are studying new electrical systems which will allow the size of the onboard generators used on aircraft to be greatly reduced, cutting their weight, and reducing the amount of energy the plane uses to take off and fly.
Generators are designed to supply both the nominal power to the loads onboard and power overloads that may occur as a result of extra load being connected to the aircraft electrical power system. Typically, they are sized according to the five-minute, five-second rule, which means that the generator can be overloaded for five minutes with a power of up to 150% of its nominal rated power, and for five seconds with a power of up to 200% of its nominal rated power.
This “oversizing” of the generator to cater for overloads means carrying additional weight on the aircraft, increased fuel burn and higher greenhouse emissions.
The objective of ENIGMA is to design, model, manufacture and test a high-level centralised controller aimed to clear all overloads within five seconds, eliminating the need for the five-minute overload requirement, and the subsequent oversizing of the generator, by guaranteeing that it will never be needed.
This could reduce the size of a typical generator by up to 15%.
"New electrical systems will allow the size of the onboard generators used on aircraft to be greatly reduced, cutting their weight, and reducing the amount of energy the plane uses to take off and fly."
Working with international aerospace company Leonardo, we have been testing the system on its Iron Bird aircraft demonstrator at the company’s Naples laboratories.
The project started in April 2018 and is to be completed by the end of this year.
It is part of the Clean Sky 2 programme - a public private partnership between the European Commission and the European aeronautics industry, which coordinates research and innovation between industrial leaders, universities, research centres and SMEs.
This partnership working has been vital to ENIGMA’s success: Leonardo Aircraft Division directed the project and provided the Iron Bird demonstrator for modelling and testing, Collins Aerospace Applied Research and Technology designed the algorithm for the ENIGMA controller and contributed to the project management, Aeromechs manufactured the controller board and contributed to the testing phase, while the University of Campania Luigi Vanvitelli contributed to the firmware definition and testing.
Within the University of Nottingham itself, the project offered an opportunity for cross-disciplinary collaboration between the Power Electronics, Machines and Control group, the Institute for Aerospace Technology and the School of Computer Science.
The ENIGMA system has been developed within three Clean Sky 2 projects - ESTEEM, IDEN and ASPIRE – also taking place at the University of Nottingham.
The extraordinary work being achieved within ENIGMA and these projects is paving the way towards the greener aviation of the future.
"The extraordinary work being achieved within the project is paving the way towards the greener aviation of the future."
Dr Sharmila Sumsurooah is a Senior Research Fellow in the Faculty of Engineering