A Detuning-Repeater-Based Dynamic Wireless Charging System With Quasi-Constant Output Power and Reduced Inverter Count

Abstract

High-density coil installation to achieve a smooth power transfer inevitably increases construction costs, reducing the acceptance of dynamic wireless power transfer (DWPT). In this article, a detuning-repeater-based DWPT system is proposed to provide a relatively constant power at a reduced count of inverters. Half of the inverter-connected transmitter coils in conventional DWPT systems are served as passive repeater coils. The repeater relays the power from the transmitters on both sides to take the role of the main power transfer channel when the receiver is moving towards it. A detuning method is proposed to suppress the standby currents inside the idle repeater coils by utilizing the variation of receiver reflecting impedance during the receiver moving towards/away. An optimization method to achieve less power fluctuation is designed based on the detuning rate. The tradeoff between the power fluctuation and current suppression is analyzed. The system performance against parameter variations is also performed. A 100 W down-sized prototype is developed, and the experimental results show that the proposed DWPT system can achieve a quasi-constant output power with a power fluctuation of 8.5% and a system efficiency of around 82% during the entire dynamic process.