Improving Misalignment Tolerance for the Wireless Charging System Using Multiple Coils Coupler

This paper proposes a new multiple coils coupler (MCC) comprising a transmitter with numerous circular auxiliary coils connected in series and a lightweight receiver with a circular coil to ensure high anti-misalignment ability for the wireless charging system (WCS). First, the proposed MCC's rationality is verified by analyzing the misalignment performance of the asymmetric circular coupler (ACC) with some auxiliary coils. Furthermore, a comprehensive elucidation is given, outlining the MCC's principle and structure from the magnetic field distribution and mutual inductance model. Second, combining the orthogonal experiments, Ansys Maxwell simulations, and data post-processing method, which feature a low workload and high efficiency, optimize the MCC's parameters. The design flow, misalignment performance, and parameter sensitivity analysis for the MCC are illustrated. Third, a series-series compensated WCS with a maximum system efficiency of 92.2% is constructed to demonstrate the proposed method. The experimental results show that the MCC maintains a relatively stable mutual inductance fluctuation of ±5% within a circular region whose radius is 135 mm (34% of the transmitter width). Besides, the charging current varies less than 5% within this circular region when the load resistance changes from 5 Ω to 25 Ω.