"This report describes the thermal effects and marine fouling on an undersea wireless power transfer system. The coils used in this wireless power transfer (WPT) experience elevated temperatures because of the resistive losses in the wire. Urethane and epoxy prevent water intrusion, but are thermal insulators and can lead to coil failure. Several different coating strategies to both protect the coils against seawater and dissipate the generated heat are investigated. In addition, the rise in temperature can increase the likelihood of marine biofouling on the exposed coil surfaces. A biofouling study on the wireless power transfer coils and whether there might be increased microbial growth as a result of the power transfer is also explored. The main benefit to the study provided here is to begin to gain an understanding of the effects thermal and marine fouling would have on WPT efficiency. The analysis will show that handling the heat should be a priority when implementing a high-power WPT system for unmanned underwater vehicles (UUVs). Coils must be carefully designed to dissipate the heat buildup but still maintain good transfer efficiency. Fortunately, the analysis will also show that the elevated temperatures on the coils is at a biocidal level, effectively killing off any marine microbes."
Technical Report 2056
Defense Technical Information Center (DTIC): http://www.dtic.mil/