A Novel Coupled Winding Nonisolated Quasi-Z-Source High Step-Up DC–DC Converter With Low Input Current Ripple

This article introduces an innovative single-switch, nonisolated quasi-Z-source (qZ–S) dc–dc converter. The goal is to develop a structure with minimal input current ripple (ICR) and high voltage gain relative to the duty cycle. The ICR is nearly eliminated by incorporating a small inductor alongside single-core coupled inductors (CIs). Increasing the turn ratio of the CIs within a voltage multiplier cell enhances the voltage gain while reducing voltage stress on the semiconductors. The proposed converter also features soft switching in the diodes and a shared ground between input and output. It employs a single <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> switch to achieve these benefits. The performance of the new converter is evaluated and compared with other z–source and qZ–S converters. Experimental results from a 315-W prototype confirm the theoretical analysis, demonstrating a voltage gain of 12 and an efficiency of 94%. The input current ripple is less than 5%, the lowest among similar converters and other approaches like interleaved converters. These characteristics make the converter highly suitable for renewable energy applications such as photovoltaic and fuel cell systems.