Study on a capacitive coupling wireless power transfer with electric vehicle's dielectric substrates for charging an electric vehicle

This paper studies a capacitive coupling wireless power transfer (CCWPT) for charging electric vehicles by using the dielectric substrate outside of a vehicle. The CCWPT can replace a conventional inductive coupling wireless power transfer because it has less electro-magnetic interference (EMI) and heat dissipation. However, since the CCWPT has limitation on transferring high power due to too small coupling capacitance, it is hard to transfer large power and high voltage is generated. In this paper, it considers the substrates outside of a vehicle to obtain the large coupling capacitance. Furthermore, a proposed CCWPT employs a new power conversion circuit to obtain high efficiency and large power transferring with the implemented coupling capacitance. The new CCWPT circuit uses glasses in a vehicle and LLC resonant operation with two transformers to reduce a switching loss of power conversion circuit. As results, the proposed capacitive power transfer can transfer large power and have good efficiency. Verification of operation and features of the proposed system shows with a 200W prototype.