A class of Sepic-based DC-DC converters with improved voltage multiplier cell

This article introduces a class of Sepic-based DC-DC converters with an improved voltage multiplier cell (IVMC) for interfacing photovoltaic (PV) panels with high-voltage DC buses in renewable energy. The converters achieve a high voltage gain by optimizing the connecting of the IVMC and Sepic converter without adding additional components. The proposed converters have the advantages of high voltage gain, low input current ripple, and low voltage stress on the switch with small number of the components. Owing to the low voltage stress, a MOSFET with low on-resistance can be adopted to reduce switching and conduction losses. The low input current ripple prolongs the lifetime of the PV modules and converters. Furthermore, a lower turns ratio is conducive to reducing the volume of the coupled inductor and decreasing the leakage inductance. The passive clamp circuit recycles leakage inductance energy and limits switch voltage spikes. A detailed analysis of the operating principle and a comprehensive steady-state analysis are presented. Then a comparison with other similar converters explains the superiorities of the proposed converters. Finally, a 200 W (32 V to 380 V) prototype made in the laboratory verified the effectiveness of the proposed converter, and the experimental results are in reasonable consistent with the theoretical analysis.