In order to improve the calculation accuracy of line resistance loss of high frequency transformer

firstly

the author takes the circular conductor and Litz wire as the research objects. Considering the temperature rise effect and skin effect

the line resistance loss model of high frequency transformer at different operating frequencies is built

and the influence of temperature rise effect on DC resistance and AC resistance is analyzed. Secondly

the influence of input harmonic current on skin depth and line resistance loss is studied

and the accuracy of the model is verified according to the measured data. Finally

the variation law between the conductor cross-sectional area and the transformer line resistance at different operating frequencies is explored

and the optimal cross-sectional area of the conductor corresponding to the minimum line resistance loss at a specific frequency is obtained. The results show that when the operating temperature rises from room temperature to 100 ℃

the DC resistance of the conductor increases by 0.4% and the AC resistance increases by at least 0.1% for every 1 ℃ increase. The higher harmonics in the input current will aggravate the skin effect and increase the line resistance loss. In addition

the line resistance loss of the Litz wire is smaller than that of the circular wire.