Novel interleaved multiphase proposal for a three level neutral point clamped buck converter

This paper introduces a new multiphase phase interleaved three-level neutral point clamped (NPC) buck converter. Compared to the conventional three phase buck, this new topology allows to split the output current between two inductors, increasing the energy density and thus reducing the inductor size. Furthermore, the output voltage and current ripple can be significantly reduced and the ripple frequency is fourth times the switching one, allowing to employee a smaller output capacitance. The operating modes and switching intervals of the proposed topology are presented and discussed. A simulation model of the converter has been developed in the standalone PLECS tool, including conduction and switching loss models, based on commercial silicon carbide power devices. Extensive simulation have been performed in order to verify the effectiveness of the proposal and to highlight the specific features of this converter, mainly phase and output current ripple reduction, nested current/voltage control scheme and current sampling issues, losses and efficiency.