Active current balancing technique employing the Lunze's transformation for converters based on multistate switching cells

This paper presents the control-oriented modeling of pulse-width modulated converters which employ the multistate switching cells concept and proposes a current balancing technique able to equalize the currents through the windings of the multi-interphase transformer by means of the Lunze's transformation. The Lunze's matrix transforms the transformer winding currents to differential and common mode currents and decouples the matrix of symmetrically coupled inductances. An analysis of current balancing mechanism and modeling of the multistate switching cell-based converter is presented; where, the small-signal models of windings currents required to the control design are found. To validate the theoretical findings of this technique, the proposed current-balancing scheme is employed on a two-phase nonisolated bidirectional multistate switching cell-based dc-dc converter.