Modular Filter Building Block for Modular full-SiC AC-DC Converters by an Arrangement of Coupled Inductors

Modularity in hardware improves manufacturability of power electronics systems and reduces maintenance cost. By paralleling modular ac-dc converters, power capacity of SiC-based power conversion system can be easily expanded. However, it is questionable if any filter topology can be realized as a modular block considering not only electric and magnetic circuits, but also mechanical structure and N -1 redundancy. Considering interleaving, filters without any coupling between channels will lead to an over-design. Meanwhile, filters with magnetical coupling may suffer from complexity in mechanical structure, and redundancy. This work proposes a concept of modular filter building block (FiBB), and a configuration of coupled inductors and a boost inductor to realize FiBB. Secondary-windings of N coupled inductors are connected in series and form a separate loop similar to a current mirror. A single inductor rated for a single channel can be placed on this loop, and realize boost inductors for all channels. Circulating current can be attenuated for any N to similar level. Under a single channel fault, the faulty converter can be easily isolated from the loop, achieving N -1 redundancy. The proposed FiBB can be easily extended for any number of channels without a significant change in mechanical structure.