Wireless Charging of Electric Kick-Scooters Using Metasurface-Based Resonator Approach

Today, the electromobility sector is increasingly dominated by electric kick-scooters (EKSs), valued for their convenience, affordability, and ease of use. Integrating wireless power transfer (WPT) technology with EKS operations is crucial for developing scalable charging infrastructure in both urban and rural areas. This paper presents a novel WPT system for EKSs charging that operates at 6. 78 MHz and uses a metasurface-based resonator (MBR) as the transmitter and a shielded rectangular spiral coil as the receiver, separated by a 100 mm air gap. Through the full-wave numerical simulations, the system's electromagnetic compatibility and compliance with international safety standards regarding human exposure to electromagnetic fields are assessed. A prototype is fabricated and experimentally validated, demonstrating RF-RF power transfer efficiency of 78% under perfect alignment of the transmitter and receiver. The robustness of the WPT system is tested against lateral and angular misalignment, revealing a graceful degradation in performance; for instance, a 10% reduction in efficiency was observed for misalignment of 120 mm along the x-axis and 60 mm along the y-axis. These findings confirm the high efficiency, misalignment robustness, and exposure safety of the proposed WPT system, underscoring its strong potential for real-world EKSs charging applications.