On Optimal Construction of Interleaved Converter for minimum Circulating Current

This paper analyses the effects of increasing the number of parallel interleaved converters on the overall performance of the converter. The circulating current flowing within the parallel modules has direct relation with the number of parallel modules connected in order to construct the converter. In this paper an effort is made to identify an optimal situation in terms of number of parallel modules in case the designer has a choice to select. The paper shows that three parallel converters results into the lowest peak circulating current. The mathematical analysis to support this statement is presented in this paper, assuming the constant DC link voltage, switching frequency and module inductance for the parallel individual module and the total power of the whole converter is constant. It is shown in the paper that the maximum peak of the circulating current occurs during the zero crossing of the modulation reference. A method of reducing the circulating current by control of the modulation index is presented and shows a >50% reduction in THD. The results are confirmed by laboratory testing.