Nonisolated ZVT two-inductor boost converter with a single resonant inductor for high step-up applications

Abstract

The interleaved operation of a two-inductor boost converter system is a very attractive solution for converting the low input voltage (30-50V) of distributed power sources, such as photovoltaic and fuel cells, to the high output voltage (380V/760V) required in grid-connected power conversion applications. However, a soft switching method is required in the two main switches to increase the overall power conversion efficiency. This paper proposes a zero voltage transition (ZVT) two-inductor boost converter using a single resonant inductor to meet these needs. To satisfy the requirement of soft switching in the two main switches, a resonant cell is constructed at the output side with a bidirectional switch, two auxiliary diodes, and a single resonant inductor. This converter has advantages due to its simple circuitry, reduced size, and low cost due to a single resonant inductor. Compared to a case with a resonant cell at the input side, it does not perturb the input current of the distributed sources. Therefore, it is more suitable for stable maximum power point tracking (MPPT) operation. The validity of the proposed ZVT two-inductor boost converter is verified through experimental results.