In order to accurately estimate leakage inductance in the design of high-power medium frequency transformer（MFT）

on the basis of a one-dimensional leakage magnetic field model of MFT

we derived an analytical equation for leakage inductance of MFT by an energy method which is based on the characteristic of its distribution. Thereby

the conductivity of the winding and calculation altitude of the leakage magnetic field was corrected based on the difference between idealized assumptions and actual situation. Moreover

leakage inductance of two prototypes was calculated and measured from 50 Hz to 10 k Hz

verifying that error could be reduced to less than 5% by correcting both the parameters. The reasons for the still existing error were analyzed. The comparison between prototype 1 and 2 demonstrates that cross arrangement for the windings can reduce the leakage inductance value of the transformer.