Efficiency and Loss Analysis of Circular, Square and Round-Cornered Square Coils in Wireless Power Transfer System—A Comparative Study Using Ansys Maxwell 3D

The research utilizes Ansys Maxwell 2024 R2, a 3D Finite Element Analysis (FEA) software, to compare the electromagnetic coil parameters, losses, and efficiency of planar spiral circular, square, and round-cornered square (RCS) coils for wireless power transfer (WPT) systems in electric vehicle (EV) applications. This study focuses on key coil parameters such as self-inductance, mutual inductance, and the coupling coefficient, which are crucial for determining power transfer and system efficiency. While analytical calculations for these parameters are straightforward for air-core transformers, they become complex and inaccurate when ferrite cores are incorporated to improve efficiency. Ansys Maxwell overcomes this challenge by employing a numerical method. Simulation results indicate that RCS coils offer uniform magnetic field distribution and reduced losses, similar to circular coils. They also exhibit better coupling and good misalignment tolerance, akin to square coils. These characteristics suggest that RCS coils are a superior choice for WPT applications. Electro-thermal management (ETM) co-simulation of the RCS coil is performed and analyzed using Ansys Icepak 2024 R2. Furthermore, an Ansys Twin Builder 2024 R2 co-simulation of a double-sided LCL-compensated WPT system, incorporating the reduced-order model of the RCS coil, is performed. Under standardized EV conditions, say 85 kHz, 35 mm, and 50 Ω load, the RCS coil achieves an efficiency of 94.81%. The research also includes loss analysis and misalignment tolerance studies, confirming the superiority of RCS coils.