A WPT System With DC-Link Series/Parallel AC-Link Parallel Rectifiers for AUVs With Multiple Charging Voltages and Currents

Due to the diversity of battery types and capacities, wireless power transfer (WPT) systems for autonomous underwater vehicles (AUVs) have large variations in charging voltages and currents. Conventional solutions of using dc–dc converters to adapt to different specifications may cause increased cost and volume and reduced overall efficiency. To address this issue, this article analyzes the special requirements of the AUV WPT systems. Then, a new AUV WPT system with dc-link series/parallel ac-link parallel rectifiers is proposed for different charging voltages and currents. The generalized mathematical model of the proposed system is presented. The natural current-sharing and voltage-sharing characteristics of the rectifiers are analyzed. In addition, design considerations of the transformers and a detailed design guideline are given. An LCC-S WPT prototype with charging voltages of 48 V and 72 V is developed. The output current ranges from 8 A to 36 A and a maximum dc–dc efficiency of 92.1% is obtained under different power transfer distances, which demonstrates the feasibility of the proposed system.