Characteristics comparison of interleaved inductor-coupled double dual boost converters

Recently, low output voltage fuel cell (FC) stacks tend to be used because cell voltage balance control on the FC stacks with small number of series connections is easier than that on those with large number of series connections. In those situations, a boost converter with low input current ripple and high voltage boost ratio is required because large output current ripple in fuel cell degrades the fuel cell performance and lifetime. As one of such converters which meet those demands, an interleaved inductor-coupled double dual boost (IIDDB) converter has been proposed. This paper proposes two types of new IIDDB converters, which have two diodes added to the previously proposed IIDDB converter. In addition, the characteristics of each type of proposed IIDDB converters are compared in the experiments. As a result, it is shown that the converter in which diodes are connected between the input and output terminals of the coupled inductors in order to bypass the inductors can obtain highest boost ratio among the proposed converters at duty ratio of 0.5 in the switches.