A Misalignment-Tolerant AUV-Capable Magnetic Coupler for Underwater Wireless Charging Systems

In the underwater environment, autonomous underwater vehicles (AUVs) have seen substantial use in the submarine environment. To avoid surfacing the AUV for recharging, magnetic coupler (MC)-embedded docking stations and AUVs for underwater wireless charging have attracted much attention in recent years. In this article, we propose a misalignment-tolerant, light-weighted, AUV-capable MC structure for underwater wireless charging applications. With the proposed design, the MC can provide a relatively stable coupling even under various types of coil misalignment. We also provide an analytical method to estimate the mutual inductance of the proposed MC under different positions. Simulations on the MC design are performed by using ANSYS Maxwell to evaluate its performance under different misalignment scenarios. To verify the viability of the proposed MC in an inductive power transfer system, a 750-W wireless charging experimental prototype was built in the laboratory with the proposed MC design. With a light-weighted and compact receiver of 320 g and 110 cm³, the system can achieve a maximum efficiency of 93.1%. Even under different coils’ axial, rotational, and off-center misalignment scenarios, the measured system efficiency is over 92%.