Low Loss Non Air Gap Multi-Permeability Planar Inductor Design for Totem-Pole PFC

A optimized magnetic core structure without air gaps and made of two different permeability materials for planar inductors is proposed. In this paper, the effect of filling the magnetic yokes with different permeability magnetic materials on improving the magnetic field distribution around the PCB windings is discussed. In order to optimize the magneto motive force distribution in planar inductors, the magnetoresistance distribution of the multi-permeability magnetic core is designed. The theoretical analysis based on Ampere's loop theorem and 3D FEA simulation results demonstrate the effectiveness of the proposed optimized magnetic core structure in reducing copper losses. And the efficiency of CRM PFC can be improved by about 0.41% by using the proposed optimized magnetic core structure.