An Integrated Non-Isolated Full-Bridge Converter with Soft Switching

Switching performance and semi-conductors' stresses are among the important factors which affect the operation of power electronic converters. The aim of this paper is to propose and analyze a non-isolated high step-up DC-DC converter in which all semi-conductor devices work in soft switching conditions and a reduced voltage stress appears across the semi-conductors. The proposed converter uses a three-winding transformer in a full-bridge structure. To minimize the voltage stress of the output diodes, they are connected in series with port of the converter. The converter is switched with a phase shift strategy and utilizes the magnetizing and leakage inductances of the transformer to achieve soft switching performance. Furthermore, the secondary and tertiary sides of the transformer supply the output load in an interleaved structure which results in a lower output current ripple. The proposed structure not only reduces the voltage stress, but it also provides high voltage gain. The design consideration equations are presented in the paper. Moreover, a 400W experimental prototype of the converter is presented to validate the operation of the converter.