Two-dimensional magnetic circuit modeling and frequency domain calculation method for transformer cores considering the effect of air gap

The lapped area of transformer core is an important source of transformer vibration and noise due to the presence of air gap resulting in structural discontinuity and complex distortion of magnetic field characteristics. In this paper, through the refinement of the magnetic density distribution characteristics of the core lapped area, the two-port equivalent reluctance of the lapped area considering the air gap is established, which is applied to the magnetic circuit model of single-phase three-pillar transformer core, and solved in the frequency domain based on the harmonic balance theory. Finally, a laminated core test platform is constructed, and the experimental data and calculation results are compared and verified, and the results show that the excitation current, core magnetism and the measurement results are in good agreement with each other, and the error is less than 5%. This paper is of great significance for improving the accuracy of the study of the internal magnetic characteristics of transformer cores.