Multiphase galvanically isolated impedance-source DC-DC converter for residential renewable energy applications

In this paper, a novel topology of the high step-up multiphase galvanically isolated impedance-source DC-DC converter is proposed. It was derived by the input-parallel-output-parallel cascading of the asymmetrical quasi-Z-source half-bridge cells. The operating principle of the converter is explained by the steady state analysis. It was also demonstrated how the input current ripple of the converter could be decreased by increasing the number of interleaved phases. To validate our approach experimentally, a two-phase DC-DC converter with the power rating of 300 W was assembled. It was confirmed that the proposed converter is capable of ensuring the six-fold regulation of the input voltage with the maximum DC gain of 40 and peak efficiency of 94.5%.