Measurement Of Stray Parameters In High-Frequency High-Voltage Transformer And Winding Structure Design

High-frequency high-voltage transformer is a particularly important device in power supply to boost voltage and isolate signal. Its performance is directly related to the stability of power supply. To measure the performance of a high-frequency high-voltage transformer, influence of stray parameters must be taken into consideration compared with the general transformer. For high voltage can enhance electric field intensity and make the stray capacitance bigger; With the increase of frequency, impact of stray capacitance on the primary current, EMI etc. is more apparent. Stray parameters are related to the winding structure. Calculating the stray parameters by experience formula is only suitable for some simple theory analysis. How to use a reliable way to measure stray parameters and how to reduce the influence of stray capacitance by improving the winding structure of high-frequency high-voltage transformer is the key problem of this paper.Equivalent model of transformer including stray parameters is summarized and π type equivalent model is used as the basis of impact analysis and measurement of stray parameters; By measuring primary current of U-shaped winding structure transformer and sectional winding structure transformer in the same experimental conditions the sectional winding structure is verified to reduce the influence of stray capacitance.According to two-port network theory, open circuit and short circuit experiments of different winding structure transformer are carried out under different frequency. Value of leakage inductance and stray capacitance can be calculated according to the measurement results of the U-shaped winding structure and sectional winding structure transformer, stray parameters can be reduced by improving transformer winding structure.Based on finite element theory, the Maxwell2D analysis tools of Ansoft software is used to model the high frequency high voltage transformer. Distribution of electric potential, electric field and energy is obtained by simulation analysis, which was used to calculate the stray capacitance according to the theory of electrostatic field. By comparing the experimental measurement results, the feasibility of finite element analysis method was verified.