Optimization of “I” Type Shielding for Low Air-Gap Magnetic and Electric Fields Inductive Wireless Power Transfer

In an inductive wireless power transfer (IWPT) system, an “I” type magnetic shielding structure was proposed to simultaneously reduce the air-gap center region magnetic and electric fields without degrading the coil-to-coil efficiency. However, the proposed structure is difficult to implement due to the requirement of enormous ferrite materials. In this paper, the “I” type magnetic shielding design is optimized for the reduction of ferrite usage, cost, weight, and easy implementation, while maintaining nearly the same field distributions and power transfer efficiency. The optimized designs can reduce the ferrite usage by nearly 70% with nearly the same performance. The proposed methods are evaluated with a 2 kW, 30 cm transfer distance design example using finite element analysis (FEA).