Driven by the gradually increasing electrification of the transportation industry, in particular the aviation sector, the future’s electrified aircraft requires not only an improvement of the flight operation, but also an enhancement of the movement on ground. One very promising concept to improve the taxiing operation is the integration of an electric propulsion system into the aircraft’s undercarriage, also called “Electric Taxiing”. This yields a decrease of the overall fuel consumption, reduction of emissions, and improvement of aircraft maneuverability to help reducing operating times on ground. In this thesis, the performance requirements for an electric taxiing system are investigated by using self-recorded real-life aircraft taxiing drive cycle data. Based upon the system requirements, the powertrain for the electric propulsion system is sized for a commercial midsize aircraft to achieve a similar driving performance to conventional taxiing maneuvers. The sized powertrain, including the determined electric motor characteristics, is evaluated using a developed simulation model which allows testing the proposed electric taxiing system given the attained drive cycles. For the electric machine which is implemented into the wheel of the aircraft’s main landing gear, an axial flux permanent magnet (AFPM) motor with segmented stator windings is selected due to its very compact structure while providing high torque capabilities. The AFPM motor is designed and evaluated by using analytical models and three-dimensional finite element analysis (3D FEA) to fulfill the specified motor characteristics required for the electric propulsion unit. Finally, suggestions for potential improvements and future work are discussed. / Thesis / Master of Applied Science (MASc)

This research introduces a high-performance electric taxiing system (ETS) as a modern solution to improve the on-ground operations of today’s aircraft, which are conventionally powered through the main engines. The presented ETS is propelled by electric motors, integrated into the main landing gear of a state-of-the-art midsize commercial aircraft, and powered by an additional not quantified electrical energy storage system. The proposed system can therefore operate autonomously from any aircraft-internal power source, i.e. Auxiliary Power Unit or equivalent. The main objective of this work is to assess the energy consumption of the introduced ETS while considering energy recuperation due to regenerative braking. The ETS powertrain is sized to match modern conventional taxi performances that were seen in 36 self-recorded takeoff- and landing taxi driving profiles. A custom ETS simulation model was developed and simulated across all available driving profiles to confirm the desired powertrain performance and to predict the system’s energy consumption. For the purpose of enhancing the validity of these energy consumption predictions, a suitable motor controller is then designed by the use of MATLAB Simulink. An easy-to-implement switch loss model was created to predict the ETS motor controller efficiency map. Finally, the former energy consumption predictions were revised for the implementation of the motor controller and an estimated traction motor efficiency map. The results exhibit that the revised ETS simulation model was capable of refining the energy consumption. It was found that the ETS will consume up to 9.89 kWh on average if the full potential of the traction motors energy recuperation capabilities are being used. The simulation outcomes further demonstrate that regenerative braking offers great potential in ETS applications since more than 14 % of required traction energy could be regenerated to yield the above mentioned average energy consumption. / Thesis / Master of Applied Science (MASc)