Abstract

Three-phase ac filters occupy more than 30%-40% of the total power electronics (PEs) system volume. With interleaved operation, the size of three-phase line harmonic filters can be reduced at the expense of high circulating current between channels. Additional filter for circulating current mitigation is required, which contributes to incremental volume. The challenge is to achieve a truly optimized and modular solution for interleaved converters, while effectively blocking circulation. Two concepts are considered, i.e., magnetic and electrical interconnection between filter blocks for parallel converters. These interconnecting methods are integrated with conventional filter structures, such as the LCL filter, to achieve filter building block (FBB) configurations. A design procedure is formulated for the two FBB configurations to compare the loss-volume map of each FBB. Brief experimental and analytical comparison is performed to distinguish between the two topologies. It is found that from modularity point of view, the electrically interconnected FBB can be a favorable option and candidate for high power applications.