An Evaluation of Inductive Power Transfer within selected Aviation Industry Applications

Abstract

Inductive Power Transfer (IPT) enables transmission of power between loosely coupled magnetic pads through alternating magnetic fields using the principles of electromagnetism. Currently, this technology has been applied to numerous applications ranging from industrial material handling, electric vehicles (EVs), and small consumer electronic devices. However, no significant research has been reported on its use for charging onboard lightheavy commuter aircraft battery systems. Airbus Vahana is an Electrical Vertical Takeoff Landing (eVTOL) aircraft designed for urban mobility transportation. It has been proposed as the next frontier mobility service and an ideal candidate for IPT charging. Wireless EV charging systems offer solutions that are close to the required specification, but the distance between the ground to the aircraft fuselage is significantly higher. The focus of this thesis is to evaluate and develop a magnetic system that can transfer 5kW of power over a 500mm airgap to an eVTOL aircraft. A magnetic analysis was carried out using “ANSYS” to understand the likely coupling profile with variation in size of the four typical magnetic coil IPT pad structures, from which it was determined that the best candidates were the DoubleD Pad (DDP) and the Solenoid Pad (SP). Further analysis looked at the total system’s apparent power VA, and magnetic leakage flux generated, both of which showed that the DDPSP and DDPDDP combinations were the best twocoil solutions based on the overall performance. An aluminium power loss evaluation determined that the DDPDDP was preferable to minimise thermal heat on the secondary side. However, neither systems are suitable for the eVTOL application because the total system’s VA and magnetic leakage flux are higher than desired. Further research investigated threecoil magnetic topologies using an additional DD intermediate coil between the primary and the secondary pad to identify its feasibility for the eVTOL application. The total system’s VA and magnetic leakage flux of the DDPDDPSP and DDPDDPDDP threei coil magnetic topologies were considered. A PowertoWeight Ratio (PWR) analysis was also conducted on the secondary pad of these systems. The results showed that the secondary pad in both magnetic configurations could achieve over the desired 1:1 kilowatt per kilogram goal. The two threecoil systems were constructed and energised to validate the theory and showed 5kW could be transferred successfully with an airgap of 500mm to meet the specifications.