Modification of empirical core loss calculation methods including flux distribution

Abstract

Using medium-frequency high-power transformers leads to significant decrease in size and volume of high-power converters in different applications such as offshore wind farms and electric traction. However, increasing the operating frequency leads to several challenges such as increase in the core loss. Consequently, estimating magnetic loss with high accuracy is essential especially in thermal modelling point of view and temperature rise calculation. The main contribution of this study is to introduce a novel and accurate model to investigate the spatial distribution of flux density inside the core. The distribution profile depends on the characteristics of the magnetic material and the configuration of the core. The accuracy of this method has been compared with the experimental results of other studies. Variation of flux density and core loss also depend on the operating magnetisation where at higher inductions, the difference between the minimum and maximum will be decreased. Owing to inhomogeneous distribution of flux, higher portion of the core loss will be generated in the inner half of the core. Ultimately, it has been expressed that considering the non-even distribution of the flux results in higher maximum temperature of the core.