System for Wireless Charging of Battery-Powered Underwater Sensor Networks

Battery-powered Underwater Sensor Networks (USNs) can have limited durability owing to their battery life. This paper proposes an energy delivery system for wireless recharging of USNs using a Remotely Operated Vehicle (ROV), which allows us to extend their lifespans and reduce waste. The wireless charging system’s efficiency is maximized using 3-D Finite Element Analysis (FEA) and an analytical loss model to design and optimize the magnetic coupler. We evaluate the proposed method using a prototype and provide experimental results for coils submerged in water at different salinity levels. These results are also compared with coils placed in the air. A detailed analysis of system operation with changes in the surrounding medium is presented. When operated at an output power of 50 W and an output voltage of 15.6 V, the developed prototype works at a best-case efficiency of 90% with coils submerged in a seawater medium.