A 3-Leg Interleaved TP PFC with a 90◦ Phase-Shifted Asymmetric Leg for Reduced Magnetics

Abstract:
In this paper, a novel approach utilizing an asymmetric switching leg is introduced, in which the inductance of one leg is halved, and unconventional phase-shifts are applied between the legs. By canceling out the 2nd harmonic of the input current ripple present in the EMI spectrum while maintaining the 3rd harmonic at the same level as in the symmetrical 3-leg interleaved version, the differential-mode filter requirement remains the same while one of the inductor size is reduced. The proposed asymmetrically phase-shifted converter shows better performance in terms of volume of input inductors (17% reduction) and overall cost (11% reduction) compared to its conventional counterpart.