Feature Analysis on Iron Loss Behaviors of Various Soft Magnetic Cores under DC Bias Fields

To realize a highly efficient power converter, it is very important to reduce the energy loss of passive magnetic components such as transformers and inductors in the high frequency region. Core loss behavior under DC bias magnetic fields is crucial for characterizing inductor performance. Various core loss behaviors have been reported so far, that is, the iron loss of some cores decreases with the DC bias fields while that of the others increases. These various core loss behaviors under DC bias fields have not been fully elucidated. In this study, the parameters for core loss behaviors under DC bias fields were investigated through the feature extraction of B-H curves of various soft magnetic cores with different materials and different permeabilities. Principal component analysis revealed that the slope and curvature of B-H curves are major components that are strongly correlated with core loss. Changes in the slope and curvature were found to positively and negatively contribute to core loss, respectively. Therefore, the various core loss behaviors under DC bias fields are understood to be a consequence of these two competitive factors.