Ensuring Safe and Reliable Wireless Charging of Unmanned Aerial Vehicles: The Imperative for Foreign Object Detection Methods

Wireless power transfer (WPT) technology has gained widespread attention in recent times due to its advantages over conventional plug-in charging methods. Among the different WPT technologies, inductive power transfer (IPT) is the most established and widely used. However, the presence of metal objects such as coins or keys in the charging area can negatively impact the charging process and even cause fires in worst-case scenarios. Strong magnetic fields can also cause medical conditions in living beings with medical implant, such as pacemaker, due to eddy currents. Therefore, it is crucial to address these issues in WPT systems. This article explores various methods to detect foreign metal objects in WPT systems. For this purpose, WPT coils were designed for a 105W system and the effect of foreign metal objects was analysed using Ansys Maxwell 3D software. A comparison of magnetic flux density distribution with and without the presence of a foreign metal object at a particular position on the transmitter coil was evaluated. Ohmic loss in the metal object was calculated using the field calculator and thermal analysis was performed using Ansys Icepack. Overall, mitigating the impact of foreign metal objects is essential for the safe and efficient operation of WPT systems.