Sensor Systems Laboratory

Deep Sea Power and Communication Links

Summary

The Sensor Systems Lab is working with the UW Applied Physics Lab on underwater wireless power transfer and communication. We are collaborating with David Dyer and Bob Michimoto to transmit power wirelessly via WREL at 1000m depths beneath sea-level to charge power base stations. Tests have shown that the power transmission gain decreases in sea-water compared to air, and even fresh water. However, by modifying coil size and various parameters, this loss can be minimized. We have conducted tests to examine the effects that salt water and fresh water have on the wireless power transfer efficiency at both small signal levels, and at high power levels suitable for power transfer. The image on the left above shows a test tank for evaluating power transfer efficiency through seawater.

The center image shows a data logger to be deployed at an undersea thermal vent. The 4 buoys are released and float to the surface at 3 month intervals, ferrying data from the seabed to the surface. When the buoys reach the surface, they uplink the data to the Iridium satellite network.

The right image is a coil, potted for underwater deployment, that is built into the buoys and data logger base. The data is communicated from the base to the buoys with a short range underwater inductive wireless link, so that a wet-mate electrical connection does not have to be broken to release the buoys to the surface. The Sensor Systems team designed and built the Inductive Communication Link for the Applied Physics Lab. The coil shown is also suitable for power transfer.