Advanced Design of Auxiliary Searching Coil for Autonomous Wireless EV Charging Robot Considering Various Shapes of Secondary

This paper proposes an auxiliary coil for identifying the shape of a secondary pad for wireless charging of electric vehicles (EVs). The proposed coil identifies the shape of secondary pad through magnetic coupling with the secondary pad. Therefore, the shape of coil is designed to show the different magnetic properties for each secondary pad, and the accuracy of this design is verified through finite element method (FEM) simulation. Furthermore, the operation method of the secondary pad identification circuit is described. The appropriate magnitude and time of the pulse voltage applied to this circuit for the secondary pad identification is derived through simulation. Finally, the performance of the proposed identification coil set is verified by experimental results.