A High Gain Transformer-Less DC-DC Converter for Fuel-Cell Applications

In this paper analysis and design of a new transformer-less high gain DC-DC converter for fuel cell inverters is presented. Due to the low input voltage in fuel cell applications a high voltage gain DC-DC converter is required. Typically to meet this requirement transformer based converters are used, with the consequent cost and size increase. As an alternative to the traditional solution the proposed converter provides a voltage gain of 5 in per unit without the need of a transformer. This contributes to a significant reduction in size and cost while maintaining high conversion efficiency. Moreover the proposed converter produces a split DC-link which can be independently controlled. This feature is ideal for bi-phase inverters to produce an AC output from a fuel-cell energy source. Converter analysis, and experimental results obtained from a 1 kW 45 V dc to 200 V dc prototype are presented in this paper