Efficiency Improvement Strategy Based on Frequency Reduction With Constant Current Characteristic for Underwater Wireless Power Transfer Systems

作者：Han Hu, Hongsheng Hu, Fengwei Chen, Xin Dai, Yue Sun · 发表于：IEEE Transactions on Power Electronics · 年份：2025 · DOI：10.1109/tpel.2025.3564961 · 被引用次数：12 · 研究领域：Wireless Power Transfer Systems、Energy Harvesting in Wireless Networks、Underwater Vehicles and Communication Systems

In this article, the problem of efficiency optimization for underwater wireless power transfer (UWPT) systems is considered. The main reason for efficiency degradation in UWPT systems is the eddy current loss (ECL) caused by seawater, which is proportional to the square of the system operating frequency. To alleviate ECL, an efficiency improvement strategy based on frequency reduction with constant current characteristics is developed. By introducing a constant gain frequency reduction (CGFR) module designed conformally with the magnetic coupler of the original system, the receiving coil ECL reduces. In contrast, the transmitting coil ECL remains unchanged, indicating an increase in power efficiency. The CGFR module does not need to add any additional converters or controls, nor does it rely on communication, resulting in strong universality. By circuit analysis, a simplified equivalent circuit of the proposed system is established, and the losses of the proposed system are analyzed, on this basis, the parameter configuration of the CGFR module is given. A 1.5-kW prototype with a coupling coefficient of 0.07 is built, and experimental results show that the proposed CGFR module indeed improves the efficiency when the load varies in the range of [5, 12] ohms, with a maximum increase of 7.8%. The proposed strategy can significantly improve the efficiency of the UWPT system, and it is particularly applicable in scenarios of long-distance transmission.