Optimized coupling factor design of multiple-phase coupled inductor for minimum inductor current ripple operation in EV charger systems

The magnetic coupling of filter inductors is widely utilized in various power electronics application fields including dc-dc converters in EV charger system in order to enhance the filtering performance while maintaining the minimal filter size. The optimal distribution of self and mutual inductance of coupled inductor is regarded to be one of important design tasks with respect to the coupled inductor. This paper proposes a novel method to design the optimal coupling factor for a generalized n-winding coupled inductor which generates the least size of inductor current ripple in phase-staggered multi-paralleled dc-dc converters. The explicit mathematical form of optimal coupling factor for a generalized n-winding coupled inductor in n-phase staggered multi-paralleled dc-dc converters is presented. Experimental result based on the HILS setup has successfully confirmed the newly proposed method of obtaining the optimal coupling factor.