Effects of Cross-Coupling on EV Position Detection of Dynamic Wireless Charging Systems

Wireless charging while in motion through dynamic inductive power transfer (DIPT) provides multiple benefits for electric vehicle (EV) users. A DIPT system consists of transmitting (TX) coils on the ground and a receiving (RX) coil mounted at the bottom of an EV. Accurate position detection and synchronisation between TX and RX coils are essential to enable DIPT. However, for three-phase DIPT systems, the TX coil structure can result in cross-coupling effects that impact the accuracy of the position detection schemes. Therefore, this paper discusses the coil structure types that result in cross-coupling effects and investigates the impact of cross-coupling on position detection accuracy. The investigation is undertaken through a proposed mathematical model that is based on symmetrical components for distributed coil structures. Using the proposed model, it is shown how cross-coupling affects the position detection schemes based on reflected impedance measurements. The results are presented for a three-phase DIPT with distributed coil structure, and it is shown that conventional position detection schemes based on reflected impedance cannot be used. Therefore, new approaches are required.