A Discrete Coupled Multiphase Interleaved LLC Converter With Symmetrical Components Analysis

This article proposes a coupling structure and a generalized analysis approach for multiphase interleaved LLC converters that applies to all odd phases that can simultaneously improve the current balancing in all interleaved phases. First, a discrete coupled inductor array (DCIArray) structure is proposed, and its magnetic circuit model is analyzed in detail; then, the generalized symmetrical component theory is introduced to decouple the inductance matrix to the sequence impedance, with expansion to all odd-phase LLC converters, and then, the sequence impedance, coupling coefficient, components tolerance impacts, and extended voltage gain with control architecture are discussed under the corresponding models; finally, the recommended design for three-phase and five-phase DCIArray was discussed. Experiments based on both three-phase and five-phase prototypes have proved that the proposed scheme has excellent current sharing in almost all frequency ranges.