Combining Sound and Magnetic fields to transfer power through Seawater and Metals (CoSoMaSaM)

Autonomous systems have become an increasingly important part of modern maritime combat, and the US Navy has recognized numerous applications ranging from cargo delivery and mine warfare to persistent surveillance and strike capabilities in its Technology Strategy. The Navy currently fields numerous unmanned surface, underwater and aerial vehicles (USV, UUV and UAVs respectively) ranging from soldier-borne drones to large unmanned surface vessels.  Across the Navy’s unmanned platform portfolio, energy and endurance is one of the Navy’s top strategic priorities with significant challenges in the energy density of available battery technologies. In one example, submarine launched UUVs provide a unique capability for clandestine information gathering due to their ability to enter shallow waters and operate autonomously. Current technology, however, requires periodic recovery and docking into the host submarine at significant risk to both submarine and unmanned vehicle. Wireless power is a promising alternative removing the need for docking UxVs for recharge, and standards already exist for charging electric cars with tens of kilowatts up to ten inches with the possibility of hundreds of kilowatts across a similar gap in the near future. However, maritime application of the technology presents a number of important challenges. For recharging a vehicle such as UUV, power must be transmitted not just through a conducting medium, seawater, but also through metal layers several millimeters thick to avoid breaching the hulls of the unmanned vehicle and support vessel. In this project, we propose a wireless power transfer solution that combines the use of both sound and magnetic fields. Such a solution enables non-intrusive, effective power delivery through metal and sea water, and suits Navy applications such as underwater charging of UxVs.