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Recently, the studies of wireless power transfer (WPT) to electric vehicles in motion on the snow-piled road have been reported. In WPT by magnetic field resonance method, transmission coefficient S21, which is one of the scattering parameters, from transmission coil to received coil are degraded because of misalignment of transmitting and receiving coil, the distance between these coils, and the effects of the ice and snow. This paper adopts parasitic coil as a solution to improve the reception power in which the parasitic coil is inserted between transmitting and receiving coils. Analysis and experimental results show that parasitic coil could improve the value of S21 by 15 dB using mutual coupling. LED could be light by this solution when the distance between transmitting and receiving coils are 150 mm. [ABSTRACT FROM AUTHOR]

In areas where snow has accumulated, it is necessary to consider the effect of snow on the wireless power transmission (WPT) system. This study focused on the variation in power flow through the WPT system due to thickness variation of ice and the dielectric constant of snow. A measurement system was created and power flow measured as S- parameters to study snow and ice influence. It was found that ice cover caused the WPT coils to detune, which when asymmetric caused high losses. However, completely filling the space between the coils with ice caused equal frequency shifts in both coils allowing the WPT system to operate at the shifted frequency. [ABSTRACT FROM AUTHOR]