ACTIVE phase-shift control of multi-phase converters to minimize input current sub-harmonics

Tolerance parameters limit the ripple cancellation phenomenon of an interleaving concept in multiphase converters. An analysis has been performed to demonstrate that coupled inductors help to reduce the influence of non-uniform inductances. Non-equal duty cycles and non-ideal phase-shifts are therefore more problematic in multi-phase converters with coupled inductors. This paper presents a control concept to optimize the phase-shifts and equalize the single pulse-widths especially for converters with coupled inductors. A prototype converter has been built and tested to show that filter components can be reduced with the proposed control technique. Theoretical predictions are compared with measurements on a full-size automotive dc-dc converter with six interleaved phases.