A Quadratic Single‐Switch Ultrahigh Step‐Up DC‐DC Converter for Distributed Photovoltaic Systems

This paper presents a single‐switch quadratic high‐gain DC‐DC boost converter integrating a quadratic structure, three‐winding coupled inductor (TWCI), and voltage multiplier unit. The proposed topology achieves a high voltage gain of 9.6 under D = 0.25 conditions, reduces voltage stress across the switching device, thereby minimizing post‐stage switching noise without requiring clamp circuits, and exhibits low input current ripple. Continuous input current characteristics and a common‐ground configuration make it particularly suitable for renewable energy applications. Detailed steady‐state analysis, parameter design optimization, loss distribution evaluation, and small‐signal modeling are provided. Comparative studies with existing converters demonstrate its superior performance in efficiency and voltage stress reduction. Experimental validation through a 400 V/200 W prototype confirms the theoretical analysis, and according to the experimental results, a peak efficiency of 94.218% was achieved under 140 W of power conditions.