Optimizing One-Block Planar Coil Design for Wireless Power Transfer in Electric Vehicles: A Comparative Study

Electric Vehicle Wireless Power Transfer (EV-WPT) systems promise to revolutionize sustainable transportation by facilitating efficient charging wirelessly. The EV-WPT efficiency is closely related to the coil configuration and can be improved by introducing ferrite cores. In this study based on Ansys software, we have characterized the three major geometries used in literature and compared their efficiency with and without ferrite cores. Equivalent and inequivalent scenarios have also been considered. To ensure that the one-block planar coils approach is reliable compared to the spiral one (computationally intensive), results comparing the two approaches showed that despite a lower EMF, the one-block coils were almost identical to the spiral coils when it comes to the coupling coefficient. Hence, the choice to continue our characterization using the one-block approach for all the considered scenarios. Various coil heights were simulated to optimize design while minimizing costs and weight, confirming only a slight increase in coupling coefficient resulted in choosing smaller height for further research. Multiple adjustments of ferrite core parameters were necessary to establish an optimal configuration. The inequivalent configuration led to an increase in the coupling coefficient of up to 73% for circular coils, 105% for rectangular coils, and 83% for squared coils compared to the equivalent configuration. Results have also shown that the circular coil geometry was the only one able to achieve a coupling coefficient higher than 0.5.