AbstractHigh step‐up converters are often used in photovoltaic applications due to low voltage of photovoltaic modules. In this paper, two new topologies, obtained with the insertion of voltage multiplier cells on secondary side of isolated SEPIC, are proposed. They have the advantages of continuous input current, isolation, high efficiency, and high voltage gain, being suitable for low power applications. To perform this study, theoretical and comparative analyses are accomplished. They include a description of each converter, tables, and curves with relevant information, such as voltage gain, total voltage stress, and total current stress. Moreover, the identification of the use of coupled inductor or transformer based on the analysis of DC magnetizing current is presented. Theoretical analysis and experimental results on 37.4/400 V, 50 kHz, and 200 W prototypes of selected isolated SEPIC with voltage doubler cell and voltage quadrupler cell are presented to validate the proposed topology and concept, where the maximum efficiency obtained for the converter with doubler cell is 96.85%, while for the converter with quadrupler cell is 97.75%.