Development of a wireless charger for drones

Abstract

Drones have seen their popularity increase enormously during the last decade. The following step in the emergence of drones in our daily life is to make them completely autonomous. A part of this new challenge is to charge their batteries without any human intervention.

In this thesis, a wireless power transfer system is proposed as solution for the autonomous battery charging. A mathematical model of wireless power transmission based on magnetic resonance is first created. Based on this mathematical model, a system to convey 1 kW of power to a 48 V LiPo battery is designed and experimentally tested.

Besides the high amount of power required to charge the LiPo battery in about half an hour, conveying power to a drone comes with other challenges. Every gram that is saved inside the drone results in an increase of autonomy. For this reason, the parts of the system placed inside the drone must be carefully designed. Furthermore, excess heating must be avoided to not impair the inside of the drone.

The experimental setup also includes a power electronics topology, able to convert a DC input voltage into the AC voltage applied at the input of the emitter circuit of the wireless power transfer system.

A second part of the thesis focuses on the magnetic fields emitted by the charging system and their impact, both on human health and on the drone itself. Several shielding techniques are introduced and discussed.