A Dual-Frequency Wireless Integrated Charging System With Enhanced Mutual Inductance and Misalignment Tolerance for Electric Vehicles

This article proposes a dual-frequency topology-based wireless integrated charging system for electric vehicles (EVs), addressing limitations in existing research, including poor misalignment tolerance, uncontrolled low-voltage (LV) battery charging, and the reliance on an additional ac switch. The proposed system supports two operating modes, each operating at different frequencies (f1 and f2), enabling independent and coordinated charging of the high-voltage (HV) and LV batteries. In Mode I, the ground-side power source charges the HV battery, while the LV-side coupling coil and part of the circuit serve as a repeater to enhance the system's equivalent mutual inductance. In Mode II, the HV battery supplies power to the LV battery. Both modes share a common magnetic coupler and compensation network, improving system compactness and hardware utilization. Through the coordinated design of the magnetic coupler and topology parameters, the system achieves strong misalignment tolerance and enhanced power transfer capability. To validate the proposed system, an experimental platform was built. In Mode I, when the HV battery charging power is 3.3 kW, the maximum dc-dc efficiency is measured at 93.16%, with a charging current fluctuation of only 3.94% across a 0-100 mm misalignment range. In Mode II, the maximum dc-dc efficiency is 83.3%. Moreover, the system achieves constant current (CC) output and zero-phase angle (ZPA) input in both charging modes.