A Family of the Three‐Level High Step‐Up DC‐DC Converters With Coupled‐Inductors

ABSTRACT Three‐level (TL) dc‐dc converters have the advantages of low voltage stress on power switches, suppressed output voltage ripple, and high conversion efficiency. This research introduces a novel family of three‐level dc‐dc converters constructed with diverse bridge step‐up units. The topological derivation procedure of the presented three‐level high step‐up dc‐dc converters is elaborated in detail. Moreover, coupled‐inductors are adopted to further elevate the voltage gain of the proposed topologies. Taking the quadric three‐level high step‐up dc‐dc converter as the research prototype, the operating principle, voltage and current stress characteristics, efficiency performance, and parameter design of the quadric three‐level converter are presented. Finally, a 50‐kHz, 200‐W, 30‐V to 380‐V experimental prototype is established to verify the technical feasibility of the proposed converter. Experimental results demonstrate that the peak efficiency reaches 96.5% under half‐load conditions whereas the efficiency at rated power is maintained at 94.1%.