Transformerless Quadruple High Step-Up DC/DC Converter Using Coupled Inductors

Abstract

This paper proposes a high voltage step-up DC/DC converter by combining a coupled inductor and a voltage multiplier rectifier. The input side of the proposed converter operates in an interleaved manner with two coupled inductors connected in parallel, and the output side is composed of a voltage multiplier rectifier where two voltage doubler rectifiers are merged in series. By changing the turns ratio of the coupled inductor of the proposed converter, the voltage gain can be increased, and additional voltage gain can be obtained by combining it with a voltage multiplier rectifier. Due to the passive lossless clamping performance of the proposed method, it is possible to recycle the leakage inductance energy of the coupled inductor and voltage stress reduction can be achieved along with zero current turn-ON and turn-OFF of switches and diodes. Finally, this paper evaluates the effectiveness and practicality of the proposed method by operating a prototype circuit with an input voltage of 20V, an output voltage of 400V, and an output power of 320W. The maximum efficiency of the proposed converter is 97.2% and the efficiency at maximum power is 94.1%.