Design and industrialization of a battery charger for electric scooters based on wireless power transfer

This thesis originates from an internship conducted at Bluhub S.r.l. during which research and development activities focused on the optimization of inductive power transfer systems. Wireless power transfer (WPT) is a technology that enables efficient charging for electric vehicles without the need for cables or physical connectors. As far as mobility is concerned, shared electric scooters can replace conventional means of transportation. However, their implementation is repressed due to the limited charging infrastructure available. This thesis discusses the focus on power electronics architecture and control strategies of a new design and implementation of an high efficiency wireless charging system meant for electric scooters. This study investigates how separate power conversion stages and different compensation topologies could improve energy transfer efficiency, and selects the best combination to do so. After extensive analysis, the series-series compensation topology was chosen along with the full-bridge inverter and buck converter. Power transfer efficiency was analyzed using computer simulation for several cases of misalignment followed by real-life prototype testing. The tests proved an increase in efficiency of 10% with the respect to the prototype that has to be optimized, as well as reaching 80% optimal conditions. Stably-low performance disruption was confirmed under varying misalignment issues. To increase the adaptability of the system, future efforts will focus on integrating IoT for monitoring and smart grid capability. Also, these efforts will aim towards the integration of phase shift modulation while eliminating the DC-DC converter to lower system cost and complexity. The project aims to help advance the development of WPT technology, which would enable the construction of eco-friendly dependable urban transportation systems.