Directional antenna design for wireless power transfer system in electric scooters

This article presents a cost-effective antenna design for wireless power transfer in electric scooters. The proposed design can be applied to any commercial 48 V/20 Ah electric scooter. In this study, based on the magnetic resonant coupling theory, a circuit that satisfies SAE J2954 specifications is presented. One-directional antenna/receiver pair is designed to meet the requirements of scooter-using scenarios. The transmitting coils are set up under the chassis of the scooter. The receiving coils are embedded in the bottom layer of the chassis, where the air gap between these two coils is larger than 10 cm. Based on SAE J2954 requirements, the operation frequency is tested around 85 kHz. Under proper power supply, the battery can be fully charged wirelessly and the system is user-friendly. The experimental results confirm the desired performance and feasibility.