Design and Optimization of Asymmetrical Spiral Rectangular Pads for EV Wireless Charging

Abstract

Inductive power transfer (IPT) is a method that can be used to transfer power to electric vehicle (EV) because it's safe, convenient and reliable. In order to design the magnetic pads, a new model must be set up for every pad and the number of simulations increases exponentially which is very time consuming. This paper focuses on the EV application and presents a method of reducing the number of required simulations. The analytical calculations can be used to optimize the coils without ferrite and the finite element method (FEM) can be used to optimize the coils with ferrite. Since the results show that the coils with ferrite and coils without ferrite have the same trend of variability of coupling coefficient with varying physical size and coverage, an optimization method of magnetic pads is proposed to combine analytical calculations with FEM simulations. First the physical size of coils and the coverage of coils are optimized by using the analytical calculations. Then FEM simulations are used to optimize the ferrite arrangements and determine the coil turns. The method is confirmed via simulation validations.