Highly extendable passive current balancing interleaved high step-up boost converter using voltage multipliers

High step-up boost converters with large input current capacity are necessary for low-voltage renewable energy sources, such as photovoltaic panels and fuel cells. Interleaved converters are a suitable topology for low-voltage, large input current applications. Conventional interleaved converters, however, face a variety of challenges, such as the necessity of additional current control loops for active current balancing, increased voltage stress of semiconductors, and poor extendibility. In this paper, highly extendable interleaved high step-up boost converters with a passive current balancing and reduced semiconductor voltage stresses are proposed. Current capacities and step-up conversion ratios of the proposed converters can be arbitrarily enhanced by extending the number of phases and voltage multiplier (VM) stages, respectively. The experimental results of 500-W prototypes demonstrated passive current balancing, reduced semiconductor voltage stresses, and enhanced step-up conversion ratios.