Loss analysis of magnetic components for a solid-state-transformer

Abstract

Recently, because of research and development into SiC power devices, power converter circuits such as high-power isolated DC-DC converters (dual active bridge) using medium-frequency (MF) transformers have been proposed. The converter circuit requires the MF transformer and inductors, but these magnetic components dominate the volume of the circuit. To realize a high-power-density isolated DC-DC converter, it is necessary to analyze the losses in the MF transformer and inductors. In this paper, an iron loss calculation method based on the improved generalized Steinmetz equation (iGSE) is presented. To analyze the iron loss in detail, an analysis method which divides the iron loss into the hysteresis loss and the eddy-current loss is also presented. Further, this paper presents a loss separation procedure for the iron loss in the MF transformer and inductors. In this analysis, the iron loss analysis is performed for different operation modes of the DC-DC converter. Finally, the validity of the separation procedure is confirmed by both analytical and experimental results.