Input current analysis of interleaved boost converters operating in discontinuous-inductor-curent mode

This paper presents the basic operation of the discontinuous-inductor-current-mode (DICM) boost PFC and the improvement achieved by the interleaving technique. The PFC is constructed by at least two boost cells, each cell is kept running in DICM. Input current of the PFC is analyzed by a numerical method and the optimum power factor is calculated in different modes of operation. The calculated result is verified by experiment and presented in graphical form with detailed discussion. The result shows that the interleaving technique can alleviate the ripple current and improve the power factor. The improvement is obvious for the number of boost cells equal to 2 or 3 and the optimum power factor is improved up to 0.99 even without using an input filter.