A Novel Diagonal-Laminated Fe-Based Nanocrystalline Ribbon Shielding Structure in Wireless Power Transfer Systems

In recent years, the application of nanocrystalline materials in wireless power transfer systems has been continuously investigated. However, due to their significantly higher conductivity characteristics than ferrite, they can trigger additional eddy current losses and attenuate the transmission efficiency of the system. This article presents a novel diagonal-laminated Fe-based nanocrystalline magnetic structure, which significantly reduces the additional eddy current loss of typical flat-laminated nanocrystalline structures and possesses excellent shielding effects. The modeling and analytical calculations of magnetic shielding energy efficiency and eddy current losses are performed and discussed in conjunction with magnetic reluctance modeling and finite element simulations. The superiority of the proposed core structure is verified by comparative experiments with five different magnetic pads prototypes of wireless power transfer couplers. Results show that the shielding effect is almost comparable to that of the ferrite pads when transmitting 3 kW power. The system efficiency is higher than 93.4%. Specifically, compared with the ferrite pads, the proposed structure reduces the core weight and volume by about 15.1% and 31.9%, respectively, realizing the lightweight design and efficient operation of the system.