A Three-Coil IPT Charger With CC and CV Outputs Through Circuit Reconfiguration

High-efficiency battery charging applications require constant current (CC) and then constant voltage (CV) two-stage charging. This brief proposes a three-coil inductive power transfer (IPT) charger through circuit reconfiguration to achieve load-independent CC and CV outputs. In addition, zero phase angle (ZPA) operation can be obtained in both CC and CV modes. This IPT charger can be reconfigured as SS compensated two-coil structure with CC characteristic and S-S-S compensated three-coil structure with CV characteristic by controlling the MOSFETs in the T-type inverter. Different from existing methods such as closed-loop control, hybrid topology switching, and frequency switching, this IPT charger avoids complex controller design, redundant compensation components, additional AC switches and the associated driving circuits, frequency out of bounds issues. Therefore, the proposed system features easy control, simple structure, low cost, and close to actual needs. A confirmatory experimental prototype with 2.5A/60V charging output is built to verify the feasibility and rationality of the proposed IPT charger.