Sampled-Data Analysis of the Dual-Interleaved Boost Converter With Interphase Transformer

Abstract

By exploiting the half-cycle symmetry in the waveforms of the dual-interleaved boost converter, a small-signal, sampled-data model is developed, which includes the differential inductance of the interphase transformer and a peak current-mode controller. The model is validated by Saber simulation and experimental results from a 10-kW prototype. Significant differences are seen in the dynamic characteristics between the two operating modes: duty ratio D ≤ 0.5 or D >; 0.5. For D ≤ 0.5, slope compensation is needed to prevent subharmonic instability over an increasing range of D when the inductance ratio of interphase transformer and input inductor increases beyond 4.0. Furthermore, with D ≤ 0.5 the control-to-output transfer function becomes sensitive to the inductance ratio, whereas it is not when D >; 0.5. Also for D >; 0.5, the range of duty ratio over which slope compensation is needed reduces as the inductance ratio is increased.