New Non Isolated DC–DC Converter for Photovoltaic Applications: Ultra High Voltage Gain With Current and Voltage Stress Reduction

Abstract

This paper proposes an ultrahigh voltage gain nonisolated DC–DC converter based on a modified double boost mode (MDBM), combined with a modified switched inductor-switched capacitor (MSLSC) technique. The modified voltage multiplier technique (MVMT) is integrated with the MSLSC and MDBM using a second main metal-oxide-semiconductor field-effect transistor (MOSFET) and an auxiliary third MOSFET to achieve ultrahigh voltage gain while reducing voltage stress across power devices. The primary objective is to achieve a voltage gain exceeding 21, thereby minimizing voltage stress on power devices, such as diodes and MOSFETs, as well as reducing current stress on all power switches and diodes in the proposed converter (PC). The MSLSC works in conjunction with the auxiliary third MOSFET and the double main MOSFETs to double the voltage gain and further reduce voltage stress on power devices. Notably, all diodes in the MVMT operate under zero current switching (ZCS), and the double main MOSFETs in the MDBM, along with the auxiliary third MOSFET, experience minimal current stress even at ultrahigh voltage gain levels. This converter offers several advantages, including high efficiency, reduced voltage stress on power devices, and lower current stress on power switches compared to previous nonisolated high step up DC–DC converters. The PC is designed to boost input voltages from 30V to a variable output range of 400–650 V, delivering up to 550 W with a peak efficiency of 96.5%.