Volume 62

A Wireless Power Transfer System for Lightweight Electric Vehicles with Coreless Coils and Dynamic Tuning Technology Yu Liu，Tong Li，Siqi Li，Zhe Liu

Abstract

The shared electric bicycles are increasingly used under the goal of “carbon neutrality,” but convenient charging remains a current challenge. This paper designs a large-area Wireless Power Transfer (WPT) system based on a rectangular single-turn coreless Transmitting coil, suitable for charging of multiple lightweight electric vehicles in public spaces. The system utilizes the transmitting coil to generate a uniform weak electromagnetic field, supporting flexible placement of the receiver and enabling charging of multiple devices, adhering to the ICNIRP (International Commission on Non-Ionizing Radiation Protection) “RF EMF Guidelines 2020” to ensure human electromagnetic safety. However, in a magnetic induction power transfer system, metal foreign objects, the vehicle body, and the number of device connections can affect changes in system parameters. To address detuning issues caused by multiple device connections and metallic foreign objects, a Switch-Controlled Capacitor (SCC) dynamic tuning technique is proposed to ensure stable and efficient system operation in the Zero Phase Angle (ZPA) state. The experiments achieved a transmission efficiency of 69.957% with a single load and 73.867% with two loads. Moreover, the results indicate that the transmission efficiency can be further enhanced by increasing the input power and the number of loads.

Keywords Wireless Power Transfer (WPT); Lightweight Electric Vehicle (LEV); Switch-Controlled Capacitor (SCC); Electromagnetic Safety.