"Decoupled Power Regulation for EV Wireless Charging Systems with High-Voltage and Low-Voltage Batteries"

"Electric vehicles (EVs) typically rely on an auxiliary power module to charge the low-voltage (LV) battery from the high-voltage (HV) battery, suffering from cascaded power losses and the charging dependency on the HV battery. To overcome these limitations, this paper proposes a decoupled power regulation for EV wireless charging systems with HV and LV batteries. Instead of relying on mechanical mode-switching relays or highly customized coils, the proposed scheme shifts the decoupling paradigm entirely to the modulation layer. Based on a DC-link parallel AC-link series multi-inverter multi-rectifier architecture, the proposed scheme utilizes independent secondary-side phase-shift modulation to achieve precise and mathematically decoupled power regulation for both batteries, thereby entirely eliminating the need for additional DC-DC circuits. A comprehensive analytical model is established to evaluate the power transfer characteristics under three charging modes: simultaneous charging, HV battery charging, and LV battery charging. Moreover, a systematic design procedure is provided. Validation is performed on a 5-kW prototype. The results demonstrate that the implemented scheme efficiently manages the decoupled charging of both batteries with a peak efficiency of 92%, and exhibits excellent robustness against coupling coefficient variations."