Modeling and application of hybrid multi permeability Fe-based flexible nanocrystalline laminated ribbon core structure in WPT systems

Flexible soft magnetic materials represented by nanocrystalline have been widely used in magnetic couplers of wireless power transfer systems due to their superior electromagnetic properties and mechanical flexibility in recent years. However, the high conductivity characteristics and thinner material unit thickness of nanocrystalline materials expose additional issues. This article first proposes a general modeling and analytical calculation method for shielding energy efficiency and loss of the nanocrystalline laminated magnetic core structure. Then, a novel hybrid multi-permeability Fe-based flexible nanocrystalline laminated ribbon magnetic structure is proposed. By multi-objective optimization of the permeability, the additional eddy current loss has been significantly reduced. In addition, the transmission performance of the proposed magnetic structure is compared with five similar structures in experiments. Results show that the system transmission efficiency is higher than 93.8% when transmitting 3 kW power and has a superior electromagnetic shielding effect. The proposed structure leads to a significant reduction in weight and volume, which is conducive to the lightweight design and efficient operation of the system. The novel structure achieves a uniform distribution of magnetic flux density while enabling effective thermal management and electromagnetic compatibility of the magnetic coupler, which contributes to the long-term reliable operation of the WPT system.