Study on a New Double-layer Electromagnetic Shield Structure of a Magnetic Coupler

Wireless energy transmission (WPT) technology is a technology that utilizes space media to achieve electrical energy transmission. The WPT can effectively solve some problems of traditional power transmission, such as unsafety, unreliability, inconvenience and so on. The magnetic couple is a key component of the WPT system, and its performance has a significant impact on the further improvement of the WPT technology. In order to improve coupling performance and reduce magnetic leakage, ferrite cores and aluminum materials are widely used in the magnetic shielding layers, which will lead to the increase of volume, weight and cost of the magnetic couplers. In this paper, a new double-layer shield structure applicable to a magnetic coupler is presented. The proposed design is based on bar ferrite cores and nanocrystalline ribbons, modeled with electromagnetic simulation of a 3D finite element method. It is analyzed that the magnetic field distribution and the coupling characteristics of a DD coil in a new double-layer shielding structure. Simulation and experimental results verify the feasibility and validity of the proposed design. Compared to those of a conventional double-layer shielding structure, the amount of ferrite core is reduced by 71.2%, and the coupling coefficient is increased by 1.12%, respectively. The simulation and experimental results proved the correctness and practicability of the design of the composite shielding structure.