Rectifier-compensated fundamental mode approximation analysis of the series parallel LCLC family of resonant converters with capacitive output filter and voltage-source load

Abstract

In this paper, the application of a voltage-source Fundamental Mode Approximation (FMA) analysis to the four-element series-parallel LCLC resonant converter family with capacitive output filter and a constant voltage load is investigated. The resultant understanding of this analytical technique and the specific application allows development of an extension to the basic FMA analysis technique which is designated Rectifier-Compensated FMA (RCFMA) analysis. RCFMA analysis is a relatively simple, but very accurate analysis that provides a closed-form solution for the family of multi-element multi-resonant converters being studied, and is applicable to two-element LC, three-element LCC and four-element LCLC tank circuits for both frequency- and phase-controlled, series- and parallel-load converters. The development of voltage-source FMA and RCFMA analyses is discussed in detail and the results are compared with the more accurate but mathematically complex time-domain modal analysis which yields only numerical results. The analytical method is also compared with experimental results from a prototype converter.