Electrical taxiing and much more with Clean Sky's ACHIEVE
In alignment with the trend towards more electric aircraft, Clean Sky's ACHIEVE project brings innovative thinking to provide greener taxiing between the airport terminal and the runway as well as cleaner on-board power generation while lowering noise and emissions.
Imagine if the noise and emissions produced by regional propeller-driven aircraft, as they taxi between the airport terminal and the runway threshold, could be drastically reduced, saving fuel in the process too. And what if such a system could also be used to generate electricity for use on on-board systems while the aircraft is in flight? Both these aspirations will be possible with Clean Sky's ACHIEVE (Advanced mechatronics devices for a novel turboprop electric starter-generator and health monitoring system) project which leverages advanced generation systems, integrated power electronics, advanced control systems and intelligent thermal management, in order to develop an innovative advanced integrated mechatronic device (a form of electrical starter/generator system) for electrical power management in turboprop aircraft.
The idea is to use the mechatronic device to deliver electric power to drive the propeller when the aircraft is taxiing between the airport and the runway (or vice versa), before or after a flight, instead of using power directly from the main turbine engines. This saves fuel and reduces noise and emissions, resulting in a cleaner, safer, quieter, and more ecologically compliant environment for those who work in, or live near, the airport.
The ACHIEVE project is coordinated by the University of Nottingham and runs from January 2017 until January 2020, supported by NEMA Ltd (which specialises in the design, manufacture and testing of electrical motors, electrical generators and electro-mechanical actuators), as well as support from Power System Technology (PST, part of the Linvest group), which designs and manufactures power converters for aerospace and custom power supplies with digital controls.
The mechatronic system is composed of three different elements: an electrical machine, a power converter and a controller, and is multi-functional, efficient, reliable, compact and light, contributing towards improved and greener performing turboprop aircraft. ACHIEVE supports the Clean Sky 2 Engine ITD WP3 'Business aviation / short range regional Turboprop Demonstrator' programme led by Safran (formerly Turbomeca), which aims to develop new technologies for a high performance turboprop engine in the 1800-2000 shp class for business aviation and short range regional applications.
Clean Sky Team Leader for Engine ITDs Jean-François Brouckaert says that "This is in line with the general trend in the turbofan evolution of going to more electric engines as well as to gradually replace, for example, oil pumps, fuel pumps etc. and get rid of the accessory gearbox, so that you don't have to take off mechanical power from the engine but you can drive everything electrically. We will need an electric system in the aircraft with batteries to drive those electric fuel pumps, electric oil pumps, etc., but with ACHIEVE the generator is on the engine to provide more electrical power wherever it is needed".
The project is now in the Critical Design Review phase, and after testing at Nottingham University the ACHIEVE system is scheduled to be delivered to Safran towards December for engine integration.
"The system, which will be integrated in an aircraft engine gearbox, will allow aircraft to switch off the engines completely and use the battery and motor to drive the propeller which propels the aircraft along the taxiways between the runway and the airport terminal" says Dr. Tao Yang, assistant professor of aerospace electric power systems at the University of Nottingham, and coordinator of the ACHIEVE project. Dr. Yang’s PhD research within Clean Sky on “Modelling electrical power system for more-electric aircraft applications” resulted in him winning the inaugural “Clean Sky Best PhD Award” in 2016.
"The success of ACHIEVE will contribute to attaining the ACARE goals by reducing CO2 and NOx pollution as well as noise emissions" says Dr. Yang. "Compared with a state-of-art electrical generator which only delivers 5kW, the ACHIEVE system will deliver more than 20kW when running as a generator. And in terms of high-power density the system is expected to deliver >10kW/L. Additionally, it uses advanced thermal management to operate within a 110°C ambient temperature".
EU Programme Manager at the Institute for Aerospace Technology in Nottingham, Hitendra Hirani, adds that "We're trying to get the benefit out of this green taxiing functionality without adding weight to the aircraft, and we've found ways of compressing the power electronics and the motor generator into one unit, rather than following the typical industry way of working where they have a massive team designing the motor, another team designing the generator, and another designing the engine. When they start plugging things together there are holes and they have to compensate, so they end up adding extra components and you end up with a really large system".
"A really key aspect of the ACHIEVE project has been the collaboration we've had between ourselves at Nottingham University, PST, Nema and Safran" says Hirani. "It has been a really strong collaboration and really good trust that has been built between the parties. This could not have been possible without having the framework that Clean Sky provides us with".