A Cost‐Effective Ultra‐High‐Gain Single‐Switch DC–DC Converter with Direct Power Transfer for Low‐Voltage PV Applications

ABSTRACT

This paper presents a novel cost‐effective, nonisolated ultra‐high‐gain single‐switch DC–DC converter (UHGS ² C) employing a voltage lift (VL) cell and a direct power transfer (DPT) mechanism, specifically designed for low‐voltage photovoltaic (PV) applications. The proposed topology achieves an 8× voltage gain at a duty cycle of 0.5 using only a single active switch, three inductors, three capacitors, and five diodes, thereby reducing component count and control complexity compared with conventional high‐gain converters. Through the DPT mechanism, a portion of the input energy is transferred directly to the load during the switch‐on interval, thereby reducing the energy processed by the magnetic elements and lowering both switch current stress and capacitor voltage ratings. The steady‐state analysis confirms that the maximum capacitor voltage is limited to half of the output voltage (V _Cmax  = V _O /2), enabling the use of compact, low–voltage‐rated capacitors that improve power density and reduce cost. Both continuous and discontinuous conduction modes (CCM/DCM) are analyzed in detail, and a systematic design procedure, along with a comprehensive power loss model, is provided. To validate the theoretical analysis, a 200‐W experimental prototype operating at 25‐V input, 200‐V output, and 50‐kHz switching frequency was implemented. The prototype achieves a peak efficiency of 96.4%, while the closed‐loop PI control verifies stable line‐ and load‐regulation performance. Comparative results demonstrate that the proposed UHGS ² C provides a favorable trade‐off among voltage gain, efficiency, component stress, and compactness, making it a strong candidate for renewable energy applications such as PV systems.