Analysis of Phase-Shifted Full-Bridge Based dc-dc Converter Considering Transformer Parasitic Elements in Discontinuous Current Mode

In high-voltage applications, due to the use of highratio step-up transformers, the value of parasitic capacitance of these transformers is large compared to the low-voltage transformers. Moreover In these applications it is prefered to use single-capacitor filters instead of filters with inductors. In this paper a simple electrical model for two-winding high frequency transformer considering all of the parasitic elements is presented. This model is used in a full-bridge based dc-dc converter with capacitive output filter controlled by phaseshifted method. The operation of this converter in DCM is analysed and its analytical relations in different time intervals is derived and confirmed by simulation and experimental results.