A Hybrid Topology IPT System With Partial Power Processing for CC-CV Charging

For traditional inductive power transfer (IPT), a two-stage structure is commonly used for constant current (CC) and constant voltage (CV) charging, but the cascaded dc–dc converter will reduce its efficiency. In this article, a hybrid topology IPT system with partial power processing (PPP) is proposed to reduce dc–dc power loss. The power transfer channel is divided into the main and auxiliary channels, and the two channels adopt different compensation topologies. Most of the power is transferred to load through the main channel, while the dc–dc in the auxiliary channel adjusts a small part of the power to maintain output. As a result, the dc–dc's power loss and device stress can be reduced significantly. Besides, the CC and CV charging can be achieved by only controlling the dc–dc without wireless communication between the primary and secondary sides. Finally, a laboratory prototype is built to validate the feasibility of the proposed system. The results show that the system efficiency is up to 92.1% when the output is 72 V–6 A, which is 2.1% higher than the two-stage structure.