Receiver Position Detection System of Wireless Electric Vehicle Charger Based on Novel Active Beacon Structure

Wireless power transfer technology is widely used for wireless electric vehicle chargers (WEVC) due to its safety, flexibility, and convenience. However, there is an inevitable misalignment between the transmitter and receiver of WEVC, which reduces the efficiency and stability of power transfer significantly. To this end, this article proposes a receiver position detection (PD) system based on the novel active beacon structure to improve the transfer performance of WEVCs. First, the novel beacons are activated to detect the receiver misalignment accurately before power transfer, which are placed on the vehicle side. Meanwhile, the PD coil matrix is employed on the ground side to achieve large-area and precise misalignment detection. Then, the parameters of PD circuits are optimized to reduce the sampled voltage errors correspondingly. In addition, with the aid of the proposed system structure, a weighted centroid PD algorithm is given to calculate the position of the receiver. Finally, the feasibility of the proposed PD system is verified by using an experimental prototype. The experimental results achieve an offset detection accuracy of 3 mm in the area of 600 mm×480 mm and a yaw angle detection accuracy of 2
$^{\circ }$
in the area of 120 mm×480 mm.