A Dual‐Mode WPT Charging System Based on Hybrid Clamping Assistance on the Receiving Side

ABSTRACT
To meet the charging requirements of lithium‐ion batteries in most industrial applications, wireless power transfer (WPT) system must not only provide constant current (CC) and constant voltage (CV) independent of the load but also support output of multispecification. However, existing methods for achieving CC to CV switching suffer from complex control strategies and unnecessary cross‐coupling, and the output value is single. To address these problems, this paper proposes a WPT system based on hybrid clamping assistance on the receiving side, which can naturally achieve CC to CV transition. Besides this, by reconstructing the structure of the transmitting side, the system has the ability to achieve multispecification output. The system employs an integrated S‐type topology and two AC switches on the transmitting side. The receiver side employs an S‐type and LCC topology connected in parallel to the load via two half‐bridge rectifier circuits. Furthermore, to eliminate unnecessary cross‐coupling, the receiving coil adopts bipolar coil (BPC) structure. The article is composed as follows. Firstly, the decoupling characteristics of the magnetic coupler are theoretically analyzed. Secondly, a mathematical model is established and the load‐independent multispecification CC and CV output characteristics and zero phase angle (ZPA) operation of the system are analyzed in detail. Finally, an experimental prototype with the first output mode of 3 A / 78 V and the second output mode of 2 A / 65 V is built to verify the feasibility and practicality of the system.