An Integrated Inductor for Circulating Current Suppression in Two Parallel Interleaved VSCs

Parallel interleaved voltage source converters (PI-VSCs) have good performance in the terms of capacity enhancement and the output power quality improvement. However, a set of inductive filters needs to be installed between PI-VSCs to suppress the circulating current. This article presents a three-phase integrated inductor to replace this set of inductive filters. It is composed of six coils and one magnetic core. The core is formed by an outer toroidal and an inner Y-shaped sections, resulting in a simple and symmetrical structure. Mathematical model, theoretical analysis and comparative study are provided. It indicates that the integrated inductor has higher utilization of magnetic cores and it can be designed with smaller size than traditional schemes. Moreover, the proposed inductor has stronger common-mode circulation current suppression capability. This means that it can effectively suppress circulation current without the assistance of complex pulse width modulation algorithms. Its feasibility is effectively demonstrated by both simulation and experiment results.