Analysis and Comparison of Isolated Converter based Step-Down Partial Power Processing Configurations

This paper presents an analysis and comparison of step-down (SD) partial power processing (PPP) configurations based on the isolated dc-dc converter. The possible PPP configurations for SD system are analyzed based on the analysis of the port voltage of the converter. As a result, three basic SD PPP configurations and their regulation range were derived, where one type (SD-1) achieves PPP when voltage gain (Kv) is less than 0.5 and ther other two types (SD-2 and SD-3) achieve PPP at 0.5 < Kv <1. Furtherly, a comparative analysis of the two SD PPC configurations based on component stress factor (CSF) is performed to determine the optimal solution for a given system. Moreover, the effects of the transformer on the CSF are analyzed. Two different SD PPP configurations based on the same converter are designed, built and tested. Experimental results prove that SD-3 type configuration has fewer CSF than SD-2 configuration, resulting in higher efficiency (exceeds 99% overall entire output voltage).