Cascaded Boost Converter to Achieve High Voltage Boost Rate - Conduction Loss Analysis

This paper deals with a new approach to obtain a boost dc-dc converter with a very high voltage boost rate (e.g., 8 in practice or 16 in theoretical study) and a high efficiency by means of two single-ended boost dc-dc converters connected in cascade. A part of the whole study, i.e., the conduction losses produced by switches of the converter, has been descried and the results obtained so far are shown in the paper. The relation between the conduction losses and the intermediate voltage (or output voltage of the 1st stage converter) is clarified through a theoretical approach since it is the key. The validity of the theory has been confirmed through practical case study. Further, a 1 [kW] setup of the cascade system has been built and the overall efficiency marked 96 [%] under condition with input voltage of 50 [V] and output voltage of 400 [V]. It has been pointed out that the cascade system offers lower conduction losses than the traditional single-ended boost dc-dc converter. Thus, the cascade system can offer a higher efficiency under condition with a very higher voltage boost rate.