Effect of Coil Geometry on Power Transfer Efficiency in Resonant Inductive Power Transfer (RIPT) for Electric Vehicle Charging

The rapid expansion of the electric vehicle (EV) market necessitates efficient and reliable battery charging solutions. Wireless Power Transfer (WPT) technology offers a promising alternative by eliminating the physical connection between vehicles and charging equipment, addressing limitations of conventional conductive systems while maintaining comparable power ratings and efficiency. This paper investigates the factors influencing the effective transfer distance in WPT systems using coupled magnetic resonance. A detailed analysis of the relationship between coil radius and transfer distance is presented through theoretical modeling, circuit analysis, and magnetic field simulations using ANSYS MAXWELL. Results reveal that coil impedance significantly impacts transfer distance, leading to the development of a novel coil design methodology. Experimental validation demonstrates the proposed method’s accuracy and effectiveness. Furthermore, challenges associated with conventional flat square in achieving longer power transmission distances are highlighted, along with strategies to enhance power transfer efficiency and system reliability.