A New Extendable Transformerless Quasi‐Resonant Step‐Up DC/DC Converter With Low Voltage and Current Stresses

ABSTRACT This paper introduces a new expandable non‐isolated quadratic step‐up DC/DC converter with low voltage and current stresses as well as low input current ripple for renewable resources applications. This circuit is based on a double switch quadratic boost converter, which are operated in simultaneous switching patterns. Moreover, this paper uses a Cockcroft–Walton voltage multiplier (CW‐VM) cell to create high voltage gains in low‐duty cycles. The vertical structure in this circuit results in the least voltage stress applied to the circuit switching components. The voltage stresses across the active switches are mitigated with the help of two passive clamp circuits. Besides, to further efficiency improvement, a resonant cell is considered in the proposed circuit. Moreover, in this circuit, the diodes' reverse recovery problem is minimized. The theoretical operation principle, as well as the steady‐state analysis of the proposed converter, are discussed in detail. Finally, a 200 W sample prototype (25 V–400 V–200 W–50 kHz) was built and tested in the laboratory to verify the analytical results of the topology. From the experimental results, the maximum extractable efficiency of 96.2% at 120 W, and the full load efficiency of the proposed converter is about 96%.