Positioning Technique Based on Trilateration Principle for EV Wireless Charging System

Wireless Power Transfer (WPT) for Electric Vehicles (EV) is a promising technique. However, the parkinglot arrangements are very position sensitive, where a small displacement between the transmitter coil and the receiver coil may lead to severe efficiency drop and degradation in system performance. In order to offer fast and clear location information of the transmitter coil to the driver or automatic parking program, a simple positioning technique without needing any other auxiliary devices is proposed in this paper. By measuring the coupling coefficients between the transmitter and receiver coils, the location of the transmitter can be detected according to the trilateration principle. With the proposed technique, the EV can be moved to the near-perfect-coupling zone with a diameter of 20-30 cm.