A Repeater-Based Dynamic Wireless Power Transfer System With Controllable Detuning Rate for a Constant Output Profile

The dynamic wireless power transfer (DWPT) system is an ideal solution for electric vehicles as it can maintain the power supply and reduce the battery volume. However, its adoption in electric vehicle charging has been limited due to the high installation costs, low charging efficiency, and significant power fluctuations. To address these issues, a repeater-based DWPT system with a controllable detuning rate method is proposed to achieve constant output power during movement. The switch-controlled capacitor is introduced in the repeater coil to adjust its detuning rate dynamically. Based on the relationship between the output power and the mutual inductances among the active, repeater, and receiver coils, the detuning rate is controlled to reduce power fluctuations. Moreover, increasing the detuning rate under no-load conditions reduces the losses in the repeater coil. A down-sized experimental prototype of the proposed DWPT system was built, and the experimental results show that it can maintain output power with fluctuations of less than 4.8% and an efficiency of approximately 85% throughout the dynamic process. Furthermore, constant power output is maintained even when the mutual inductance between the repeater coil and the active coil varies by up to 25%.