Accurate calculation of winding losses in high-frequency transformer(HFT) is important for the optimal design of magnetic components such as HFTs. In the HFTs

Litz wire is often used to make the windings

because it can reduce the high frequency eddy current loss

so it is especially important to calculate the Litz wire loss accurately. In this paper

an analytical model based on the mirror method to extract the magnetic field is proposed to calculate the winding loss of Litz wire for HFT

in which the magnetic field is divided into two components in the analytical calculation equation of the winding loss

namely

parallel to the strand and perpendicular to the strand;moreover

the twisting angle of the strand with respect to the Litz wire bundle is introduced to characterize the twisting construction of the Litz wire

and the mirror method is adopted to extract the external magnetic field of the winding to characterize the edge effect. The two computational parts of this method are realized in MATLAB to avoid complex data interfacing in multi-software solving. Meanwhile

two prototypes were fabricated for testing to verify the accuracy of the analytical calculation method proposed in this paper.