Analytical Model of Multicoil Pad Couplers with Ferrite Core Plates in Wireless Electric Vehicle Charging Systems

Abstract

Multicoil pad couplers with a bipolar pad (BPP) transmitter and a double-D pad (DDP) receiver have emerged as one of the most promising topologies in wireless power transfer (WPT) systems for electric vehicles (EVs). However, due to their complex structure and variable excitation mode, solving the process of the coupler parameters based on finite element models (FEMs) can be time-consuming and resource-intensive. In this study, the analytical model of the BPP-DDP coupler in different misalignment cases and under different excitation modes is developed based on dual-Fourier transformation. The mutual inductance performance of the BPP-DDP coupler in misalignment is investigated using the proposed analytical model, and the optimized excitation mode of the BPP-DDP coupler in different misalignment cases can be easily obtained. Finally, a prototype of the BPP-DDP coupler with dimensions of 600 mm × 500 mm is constructed, and the experimental results demonstrate that the computational errors of the analytical model and FEM are approximately equal, while the analytical model is 7.6 times faster than the FEM.