Core Loss Modeling and Calculation for Trapezoidal Magnetic Flux Density Waveform

This article proposes a novel approach in order to understand the different kinds of core loss of the trapezoidal flux waveform. The proposed approach is based on the theory of magnetism and assessed with the experimental results to show that the total loss is composed of two terms: the effective triangular loss during the on-time resulting from the flux variation and the relaxation loss during the off-time, which is due to the magnetic after-effect phenomenon. The study shows that the relaxation loss depends on the off-time and it has a maximum at a particular off-time-to-on-time ratio that depends on the magnetic material. In addition to that, two models with accuracy higher than 96% and with a reduced number of parameters compared to the existing models are developed to predict the relaxation loss. The models are verified with previous experimental results and new experiments performed in this article.