Development of underwater WPT system independent of salinity

We are aiming at construction of a WPT system which can keep high power transfer efficiency in water irrespective of dissolved medium by relying on our studies on the removal of dielectric effect to the system. The influence of water appears in two forms, the resonant frequency and the power transfer efficiency. The former is induced by the high dielectric constant, whereas the latter is the result of high conductivity of ionized materials including water itself. We have clarified that the resonant frequency is made quite stable and dielectric loss induced from the imaginary part of dielectric materials is also reduced appreciably by use of magnetically coupled resonators. Though it is not known whether the power transfer loss arising from ionized particles is also reduced by the same resonator systems, we have tried on the line of the same concept, investigating unloaded Q value of the magnetically coupled resonator systems under various conditions. As a result, when we fabricate the transmitting and receiving resonator of 2-layered coil resonator using resonator diameter of 30cm with litz wire, and the resonant frequency of 100 kHz, the efficiency approximately 88% is obtained at the same salinity with seawater for the resonator distance of 15cm.