Mesh-Based Accurate Positioning Strategy of EV Wireless Charging Coil With Detection Coils

Wireless charging technology greatly improves the flexibility and convenience of electric vehicles (EVs) charging. The alignment of coils directly affects the performance of the wireless charging system. The shift of the secondary coil leads to the decrease in transmission power and efficiency. Aiming to solve the abovementioned problems, in this article a mesh-based accurate positioning strategy for the EV wireless charging coils has been proposed. The strategy takes the center of the primary coil as the origin and divides the meshed reference points in the plane of the secondary coil. It is based on the voltage principle induced by the detection coils installed on the secondary coil. The coordinate calculation formula is derived by fitting the curve of the induction voltage with distance. The centimeter-level positioning of the secondary coil is realized in the X and Y directions of the horizontal plane. The proposed strategy is verified by simulations and experiments. The effectiveness and stability of the proposed method are verified by many simulations and experiments. Without considering the rotation of the coil, the maximum error is within 3 cm in a 5 cm mesh width. The positioning strategy helps to align the coils and improves the electrical transmission performance. It is also helpful for automatic parking, unmanned vehicle, and other industrial applications.