Capacitive coupling wireless power transfer with glass dielectric layers for electric vehicles

This paper proposes a new capacitive coupling wireless power transfer for charging electric vehicles. The capacitive coupling wireless power transfer can replace a conventional inductive coupling wireless power transfer because it has no electromagnetic interference (EMI). However, the capacitive coupling wireless power transfer has limitation on charging electric vehicles due to too small coupling capacitance. Therefore, the new capacitive wireless power transfer uses glasses with a dielectric layer in a vehicle. The area and dielectric permittivity of glasses in the vehicle is large so the large coupling capacitance can be obtained. In addition, a switching loss of power conversion circuit is reduced by a LLC resonant operation with an impedance transformation. As results, the proposed capacitive power transfer can transfer large power and have good efficiency. A 1.2kW prototype is designed to verify operation and features of the proposed system and it has the 94% high efficiency in 1.2kW output power.