Loading [MathJax]/extensions/MathZoom.js
An Accurate Calculation Method of Leakage Inductance of High-Frequency Transformer With Litz Wire Winding Considering Irregular Region | IEEE Journals & Magazine | IEEE Xplore

An Accurate Calculation Method of Leakage Inductance of High-Frequency Transformer With Litz Wire Winding Considering Irregular Region


Abstract:

The leakage inductance of a high-frequency transformer affects the operating mode and performance in dc/dc converters, so it is necessary to calculate the leakage inducta...Show More

Abstract:

The leakage inductance of a high-frequency transformer affects the operating mode and performance in dc/dc converters, so it is necessary to calculate the leakage inductance accurately. In the existing analytical calculation methods of leakage inductance of high-frequency transformers with Litz wire winding, the nonarea-equivalent high-frequency analytical method is applied to calculate leakage inductance. However, the calculated leakage inductance value is lower than its actual value due to the neglect of the irregular region between turns. In order to improve the calculation accuracy, this article proposes an analytical calculation method of leakage inductance for the high-frequency transformer with Litz wire winding, which considers the irregular region between turns. The 2-D magnetic field distribution in the transformer window and attenuation caused by high-frequency effects on magnetic field energy are analyzed and applied in this proposed method, to take the energy stored in the irregular region between turns into account indirectly. Thus, the proposed analytical expression for leakage inductance is derived correspondingly. Finally, the accuracy of the proposed method is verified by simulations and experiments. The results indicate that the relative error of calculating leakage inductance can be reduced from 16.25% to 3.79% by the proposed method within a certain range of wire densities.
Page(s): 7441 - 7451
Date of Publication: 01 July 2022

ISSN Information:

Funding Agency:


I. Introduction

The leakage inductance of a high-frequency transformer plays a crucial role in diverse isolated dc/dc converters, as its accuracy affects the control and performance of converters. For example, in a dual active bridge (DAB) converter, the primary leakage inductance is in series with an inductor, which affects the zero-voltage switching of the converter and that should be taken into consideration during the design process [1]. In addition, the inductor in series with the transformer can also be integrated into the transformer to improve the power density of DAB, which depends on the accurate calculation of leakage inductance [2]–[4]. Besides, in isolated dc/dc converters, when the transformer does not accompany the series inductor, the leakage inductance should be accurately controlled. On the one hand, if the leakage inductance is too large, a lot of energy stored in the transformer during operation will cause a large spike voltage at the moment when the switch is being turned off, causing an over-voltage breakdown on the switch. On the other hand, there is a voltage drop when the current flows through the large leakage inductance, leading to the decline of the transformer gain [5], [6]. Thus, the accurate calculation of leakage inductance is of great significance for the operating mode and performance of converters.

References

References is not available for this document.