A new non‐isolated high‐voltage gain single switch quadratic modified single‐ended primary‐inductor capacitor (SEPIC) DC–DC converter is proposed in this study. The proposed converter consists of a modified SEPIC converter along with a boosting module to obtain a high‐voltage gain at a low‐duty ratio. It has all advantages of the SEPIC converter such as continuous input current, which makes it applicable for renewable energy sources such as photovoltaic systems. The proposed converter is able to attain a higher voltage gain in comparison with similar previous transformer‐less DC–DC converters. Also, unlike high‐voltage transformer‐based DC–DC converters, it does not suffer from leakage inductances. Also, the proposed converter presents low‐voltage stress across the switch and output diode. The proposed converter is controlled through a single switch and there is no limitation for a range of duty ratios. The voltage gain analysis of the proposed converter is done in continuous conduction mode and discontinuous conduction mode, also comparative analysis is done with the existing topologies with similar features. The proposed converter is designed for 400 V DC microgrid applications. The theoretical analysis of the proposed converter is verified by the experimental investigation in the laboratory.