Leakage Inductance Determination for Transformers with Interleaving of Windings

Abstract

A diversity of formulas is given in literature for leakage inductance calculation of transformers with interleaving of windings. In the paper, the meaning of included terms and details of the application for concentric and pie windings transformers shall be discussed. Considering the limitation of common formulas to magnetically symmetric transformers an alternative approach shall be demonstrated, which enables leakage inductance prediction also in the case of transformers with magnetically asymmetric arrangements of windings.

Application of the inductive high current testing transformer for supplying of the measuring circuit with distorted current

“…Therefore, it is necessary to determine the factors that condition the frequency band of operation of a traditional iron core high current testing transformer. In such constructions, the leakage inductance of windings is proportional to the square of the number of turns and relation between dimensions of the cross sections of the winding and the magnetic core [11][12][13]. More accurate results are achieved with the finite element method, but formula proposed in [11] is characterised bythe acceptable maximum relative error between values calculated and measured (not higher than 4.5% for unsymmetrical configuration of windings).…”

Power transformer for a single-stage bidirectional and isolated ac-dc matrix converter for energy storage systems

“…Moreover, a substantial reduction in leakage inductance is obtained by interleaving the primary and secondary windings which is a critical design factor for the HFLMC. The leakage inductance referred to the primary side for magnetically symmetric arrangement of windings can be estimated by the following [37]:…”

Calculation of Leakage Inductance of Integrated Magnetic Transformer with Separated Secondary Winding Used in ZVS PSFB Converter

“…Calculation of equivalent leakage inductance L eq To calculate the equivalent leakage inductance L eq , it is necessary to firstly calculate the equivalent leakage inductance of secondary winding L s_eq . L s_eq is mainly correlated with the number of turns N s12 , the average turn length of secondary windings l a , core window width along x axis b w and core window height h w [17,21,22]. The formula is shown below.…”

“…Moreover, experimental values have been measured to evaluate the computational accuracy. For the present IM transformer design showing a closed core and a very high magnetizing inductance, so the short-circuit inductance values which are measured by LCR tester (the inductance measurement at the primary side during short-circuiting the two output terminals of the both secondary sides, measuring frequency 20 kHz) is closed to the leakage values, and the measured inductance values are considered to be the sought leakage inductance values [23]. Compared with the FEA and experimental results, the error of calculation results is less than 1 μH, which means that the proposed calculation method of leakage inductance are accurate.…”

“…First yoke leakage inductance is calculated at secondary windings and then converted to primary windings. According to Lebedev [17,21], the formula of yoke leakage inductance at secondary windings L s_y is as follows: (13) where g y is a coefficient related to the geometry of the IM transformer with separated secondary winding.…”