The Optimal Placement of Ferrite in Inductive Power Transfer Coupling Pads

Inductive power transfer (IPT) system performance is critically affected by the placement of ferrite material in IPT pads. However, current placement design approaches rely on specialist knowledge and trial-and-error effort. Furthermore, these approaches depend on a given initial pad structure. Hence, design flexibility is constrained, and the performance limits of what is possible are unexplored. Therefore, this paper proposes a ferrite structure design approach based on topology optimization that maximizes the coupling performance of circular IPT pads, subject to a ferrite volume constraint. The proposed approach allows pad designs to be quickly generated, easily simplified for manufacturability, and does not depend on a given initial structure. Simulation results are presented, proving optimality in terms of mutual inductance and tolerance to IPT pad misalignment compared to an existing pad design with bar-shaped ferrite pieces. Independence of the need for an initial structure allows for novel pad structure identification and the realization of new performance levels.