Quadruple-U Auxiliary Structure-Based Receiving Coil Positioning System for Electric Vehicle Wireless Charger

Abstract

In order to strike a balance between economic development and green travel, electric vehicles with wireless charging have become one of the first choices for future transportation. Misalignment between the transmitting coil and receiving coil in wireless charging systems decreases power capacity and efficiency to a great extent. Hence, the detection of whether the electric vehicle enters the effective charging area is a hot issue in the current research. In this paper, a receiving coil positioning approach integrated with a quadruple-U auxiliary structure is proposed. The designed quadruple-U auxiliary structure with cruciform distribution consists of four U-shaped coils, which are inspired by the solenoid coil. Based on the symmetry of the auxiliary structure, a receiving coil positioning method is proposed by measuring the load voltages of each U-shaped coil working independently. Coordinates can be obtained by retrieving the measured results with the database established in advance. The positioning method has the advantages of wider positioning ranges, higher positioning accuracy, and not changing the structure of the receiving coil. Furthermore, the specific magnetic coupler is simulated by a three-dimensional finite element modeling tool and was verified by an experiment on a prototype. During the positioning process, the positions distributed throughout the ΔX ∈ [−300 mm, 0 mm]∩ΔY ∈ [−300 mm, 300 mm] positioning range were tested. The experimental results indicate that all of the tested positions are accurate to within 10 mm, with a 160 mm transfer distance. Meanwhile, combined with the symmetry of the auxiliary structure and the test results, it can be indicated that the positioning range can reach ΔX ∈ [−300 mm, 300 mm]∩ΔY ∈ [−300 mm, 300 mm].