Speaker
Description
The transformer in the power supply is naturally sensitive to the external magnetic field, and its operating characteristics are easily changed under the influence of the strong external stray magnetic field, resulting in the change of the operating characteristics of the power supply and even failure. Therefore, the establishment of an accurate transformer model under the external magnetic field is an important requirement for realizing the design of power supply immunity. Because the external magnetic field will cause the transformer core saturation and the uneven distribution of magnetic flux in the core, the traditional modelling method based on magnetic circuit is no longer suitable, and the modelling method based on electromagnetic field finite element analysis is difficult to take into account the calculation accuracy and efficiency. In this paper, a transformer modelling method considering the effect of external magnetic field is proposed based on the equivalent magnetic circuit network method. The transformer core and the external air domain are divided into several magnetic circuit units to form a magnetic circuit network. The field distribution in the model is obtained by iteratively solving the magnetic circuit network equation. The proposed method is used to model an EE transformer and calculate the field distribution and the excitation inductance value of the transformer under a uniform steady strong magnetic field. By comparing the calculated results with the finite element simulation results and the real experimental results, the accuracy and efficiency of the proposed scheme are verified.
