A Method for Tuning Leakage Inductance in Transformers

Abstract:
Being able to control the value of the Leakage Inductance in a transformer in production is becoming critical in automotive and industrial applications. This is especially true in designs for a dual active bridge topology. The coupling factor K can be calculated using FEA which takes into account the dimensions in three axes of the winding distribution and the distance between the coupled coils. However being able to guarantee the values of these variables in a manufacturing environment is not at all practical. In this paper, a novel method for tuning the leakage inductance to the target value with a tolerance of less than 10% during assembly is presented. Ansys Maxwell simulations, as well as sample design and testing are discussed here and the results show how it is possible to manually tune leakage using a two bobbin configuration.