Low-Frequency Underwater Wireless Power Transfer: Maximum Efficiency Tracking Strategy

This paper proposes a strategy to improve the efficiency of a low-frequency Wireless Power Transfer (WPT) system used to charge the battery of an Autonomous Underwater Vehicle (AUV) through an Inductive Power Transfer (IPT). The IPT system uses a Split-Core Transformer (SCT) to transfer power from the docking base to the AUV, without electric contact. Under gap variation, the efficiency is changed because the variation of SCT parameters. Therefore, the input frequency is changed in order to improve the efficiency of the system trough the Maximum Efficiency Point Tracking algorithm (MEPT) without communication between primary and secondary sides. Experimental results are presented to validate the theoretical analysis and to demonstrate the behaviour of the transformer under different values of gap and excitation frequency.